Dissertations / Theses: 'CBRAM'

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Saadi, Mohamed. "Etude des mécanismes de commutation de résistance dans des dispositifs Métal (Ag) / Isolant (HfO2) / Métal, application aux mémoires résistives à pont conducteur (CBRAMs)." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT021/document.

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Actuellement, l'étude et le développement d'oxydes à commutation de résistance pour des dispositifs mémoires (Resistive RAM, ou ReRAM) constituent un domaine d'activité intense sur le plan international. Les ReRAMs sont des structures MIM (Métal-Isolant-Métal) dont la résistance peut être modulée par l’application d’une tension. A ce jour, les mécanismes qui régissent la transition de résistance dans les dispositfs ReRAM sont toujours l’objet de débats. Le travail développé dans cette thèse représente une contribution au développement des mémoires ReRAM à base de HfO2. Nous nous intéressons plus particulièrement aux ReRAMs « à pont conducteur » (Conducting Bridge RAM, ou CBRAM) pour lesquelles la transition de résistance est provoquée par la diffusion du métal d’anode. Nous cherchons à améliorer la compréhension des phénomènes qui contrôlent le passage d’un état isolant à un état conducteur. Dans ce cadre, notre travail se focalise sur l’influence des métaux d'électrodes. Le rôle de l’anode et de la cathode sont précisés. Un modèle qualitatif est présenté permettant d’expliquer la commutation de résistance. Nous discutons également des mécanismes de conduction dans l’état de faible résistance. Enfin, l’impact de la structure de l’oxyde est étudié
The Resistive Random Access Memory (ReRAM) technology is attracting growing interest as a potential candidate for the next generation of nonvolatile memories. ReRAMs are MIM (Metal-Insulator-Metal) devices whose resistance can be tuned by voltage bias. Today the physical mechanisms at the origin of resistance switching are not yet fully understood and are still under debate. In the present work, we are interested in HfO2-based ReRAMs, with a focus on Conducting Bridge RAM (CBRAM) devices in which resistance transition is ascribed to anode metal diffusion. Our goal is to better identify phenomena which govern the high to low resistance transition. In this context, we study the impact of different metal electrodes. The role played by the anode and the cathode is elucidated. A qualitative model describing resistance transition is proposed. Conduction mechanisms in the low resistive state are also discussed. Finally, the impact of oxide structure is studied

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Nail, Cécile. "Etude de mémoire non-volatile hybride CBRAM OXRAM pour faible consommation et forte fiabilité." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT010/document.

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À mesure que les technologies de l'information (IT) continuent de croître, les dispositifs mémoires doivent évoluer pour répondre aux exigences du marché informatique. De nos jours, de nouvelles technologies émergent et entrent sur le marché. La mémoire Resistive Random Access Memory (RRAM) fait partie de ces dispositifs émergents et offre de grands avantages en termes de consommation d'énergie, de performances, de densité et la possibilité d'être intégrés en back-end. Cependant, pour être compétitif, certains problèmes doivent encore être surmontés en particulier en ce qui concerne la variabilité, la fiabilité et la stabilité thermique de la technologie. Leur place sur le marché des mémoires est encore indéfinie. En outre, comme le principe de fonctionnement des RRAM dépend des matériaux utilisés et doit être observé à la résolution nanométrique, la compréhension du mécanisme de commutation est encore difficile. Cette thèse propose une analyse du principe de fonctionnement microscopique des CBRAM à base d'oxyde basé sur des résultats de caractérisation électrique et de simulation atomistique. Une interdépendance entre les performances électriques des RRAM et certains paramètres matériaux est étudiée, indiquant de nouveaux paramètres à prendre en compte pour atteindre les spécifications d'une application donnée
As Information Technologies (IT) are still growing, memory devices need to evolve to answer IT market demands. Nowadays, new technologies are emerging and are entering the market. Resistive Random Access Memory (RRAM) are part of these emerging devices and offer great advantages in terms of power consumption, performances, density and the possibility to be integrated in the back end of line. However, to be competitive, some roadblocks still have to be overcome especially regarding technology variability, reliability and thermal stability. Their place on memory market is then still undefined. Moreover, as RRAM working principle depends on stack materials and has to be observed at nanometer resolution, switching mechanism understanding is still challenging. This thesis proposes an analysis of oxide-based CBRAM microscopic working principle based on electrical characterization results and atomistic simulation. Then, an interdependence between RRAM electrical performances as well as material parameters is studied to point out new parameters that can be taken into account to target specific memory applications

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Alfaro, robayo Diego. "Mémoires resistives pour applications Storage Class Memory (SCM)." Thesis, Université Grenoble Alpes, 2020. https://tel.archives-ouvertes.fr/tel-03103308.

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Dans les architectures classiques dites de Von-Neumann pour des systèmes d'information, les blocs de mémoire et de traitement sont séparés. Pour le premier, les temps d'accès sont beaucoup plus importants. Afin d'optimiser les performances, une hiérarchie de mémoire a été mise en place. Elle combine des technologies coûteuses, de petite taille, mais très performantes en termes de vitesse; avec d'autres plus larges, à bas coûts per bit, mais plus lentes. Dans une telle hiérarchie, un gap important existe en termes de temps d'accès et capacité de stockage entre les blocs de mémoire les plus bas et ceux de stockage les plus hauts (mémoires FLASH). Des technologies émergentes non-volatiles, appelées textit{Storage Class Memories (SCM)} sont candidates pour remplir tel gap. Entre elles, les mémoires résistives vives, ReRAM, de l'abbreviation anglaise pour textit{Resistive Random Access Memories}; représentent une alternative très intéressante grâce à leur bonne scalabilité, basse consommation, compatibilité avec la Back-End-Of-Line (BEOL), leurs temps d'écriture et lecture rapides, et bonne endurance. Cependant, plusieurs obstacles empêchent leur implémentation à l'échelle industriel, notamment la haute variabilité des états résistifs et la non-linéarité réduite entre eux, ce qui limite l'implémentation des matrices mémoires larges. Ces deux aspects sont étudiés dans ces travaux de thèse. Pour la variabilité, il se trouve que l'endurance, caractéristique fondamentale vis-à-vis des applications SCM, est aussi dispersée. Ce manuscrit présente des caractérisations électriques en endurance au niveau statistique sur des matrices ReRAM de 4Kb. Plusieurs empilements mémoires furent étudiés, ainsi qu'une grande variété des conditions de programmation pour le cyclage. Il a été observé comment la valeur médiane et la déviation standard du claquage des mémoires sont principalement affectées par le RESET. Les résultats expérimentaux ont été utilisés dans la proposition d'un modèle stochastique basé sur la génération de défauts dans la couche résistive. Concernant l'autre grand axe de cette thèse, une co-intégration réussie entre une mémoire $HfO_{2}$ (1R) et un sélecteur (1S) de type textit{Ovonic Threshold Switch (OTS)}, a été demontrée. Les courants de fuite, obtenus grâce à l'addition de l'OTS, sont compatibles avec des matrices entre 100Mb et 1Gb. Pour la première fois, à notre connaissance, des paramètres influant sur les performances des structures 1S1R ont été étudiés au niveau statistique pour des matrices crossbar à haute densité, ainsi permettant la proposition d'optimisations futures et des nouvelles études incluant des nouveaux matériaux et circuits, pour continuer à améliorer les performances des dispositifs 1S1R
In classical von-Neumann architectures, processing and memory blocks are separated. Latency times for the latter are much more slower. To boost performances, memory hierarchy has been introduced to combine small, fast, but expensive technologies with large, slower, and cheaper ones. In such hierarchy, a notorious latency and storage gap can be distinguished between the lowest memory level and the highest storage one (Flash memories). Emerging non-volatile technologies are called to fill such gap through the so-called Storage Class Memories (SCM). Among them, Resistive Random-Access Memories (ReRAM), represent an interesting candidate to improve flash performances due to their good scalability, low-power consumption, Back-End of Line compatibility, fast writing and erasing process, and good endurance. However, several roadblocks hinder their implementation at large industrial scale, notably high variability, and low non-linearity, which avoids large crossbar arrays implementation. This thesis work explores such aspects to increase attractiveness of ReRAM technologies for SCM applications. For the former, endurance variability is addressed at the array level through various measurements over diverse stacks configurations. Results allow to study the impact of programming conditions on failure mechanisms dispersions, leading to the development of a stochastic model based on defects generation inside the resistive layer. As for the non-linearity issue, successful co-integration between best-in-class $HfO_2$ and $GeSeSbN$ Ovonic Threshold Selector (OTS) in 1S1R structures, is demonstrated. Hence, leakage currents compatible with 100Mb-1Gb bank size are obtained. For the first time, to our knowledge, key parameters of OTS+ReRAM systems for high-density crossbar arrays are identified and studied at the statistical level, allowing proposition of further optimizations and opening the way to a whole field of studies which include new materials and circuits to improve 1S1R performances

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Kazar, Mendes Munique. "X-ray photoelectron spectroscopy investigations of resistive switching in Te-based CBRAMs." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS285/document.

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Les mémoires à pont conducteur (CBRAM) sont une option actuellement étudiée pour la prochaine génération de mémoires non volatiles. Le stockage des données est basé sur la commutation de la résistivité entre les états de résistance élevée (HRS) et faible (LRS). Sous polarisation électrique, on suppose qu'un trajet conducteur est créé par la diffusion des ions de l'électrode active dans l'électrolyte solide. Récemment, une attention particulière a été portée sur les dispositifs contenant un élément semi-conducteur tel que le tellure, fonctionnant avec des courants réduits et présentant moins de défaillances de rétention. Dans ces « subquantum CBRAMs », le filament est censé contenir du tellure, ce qui donne une conductance de 1 atome (G₁atom) significativement réduite par rapport aux CBRAMs standard et permettant ainsi un fonctionnement à faible puissance. Dans cette thèse, nous utilisons la spectroscopie de photoélectrons par rayons X (XPS) pour étudier les réactions électrochimiques impliquées dans le mécanisme de commutation des CBRAMs à base de Al₂O ₃ avec des alliages ZrTe et TiTe comme électrode active. Deux méthodes sont utilisées: i) spectroscopie de photoélectrons par rayons X de haute énergie non destructive (HAXPES) pour étudier les interfaces critiques entre l'électrolyte (Al₂O ₃ ) et les électrodes supérieure et inférieure et ii) les faisceaux d'ions à agrégats gazeux (GCIB), une technique de pulvérisation qui conduit à une dégradation plus faible de la structure, avec un profilage en profondeur XPS pour évaluer les distributions des éléments en profondeur. Des mesures ToF-SIMS sont également effectuées pour obtenir des informations complémentaires sur la répartition en profondeur des éléments. Le but de cette thèse est de clarifier le mécanisme de changement de résistance et de comprendre les changements chimiques aux deux interfaces impliquées dans le processus de « forming » sous polarisation positive et négative ainsi que le mécanisme de « reset ». Pour cela, nous avons effectué une comparaison entre le dispositif vierge avec un état formé, i.e. l'échantillon après la première transition entre HRS et LRS et un état reset, i.e. l'échantillon après la première transition entre LRS et HRS.L'analyse du « forming » positif pour les dispositifs ZrTe / Al₂O ₃ a montré une libération de Te liée à l’oxydation de Zr due au piégeage de l'oxygène de l'Al₂O ₃ sous l’effet du champ électrique. D'autre part, pour les dispositifs TiTe / Al₂O ₃, la présence d'une couche importante d'oxyde de titane à l'interface avec l'électrolyte a provoqué une dégradation permanente de la cellule en polarisation positive. Pour le « forming » négatif, nos résultats montrent un mécanisme hybride, à savoir une combinaison de formation de lacunes d'oxygène dans l'oxyde provoquée par la migration de O2- entraîné par le champ électrique vers l'électrode inférieure et la libération de tellure pour former des filaments conducteurs. De plus, les résultats obtenus par profilométrie XPS et ToF-SIMS ont indiqué une possible diffusion de Te dans la couche d'Al₂O ₃. Lors du « reset », il y a une recombinaison partielle des ions oxygène avec les lacunes d'oxygène près de l'interface TiTe / AlAl₂O ₃ avec une perte de Te. Un mécanisme hybride a également été observé sur les dispositifs ZrTe / Al₂O ₃ pendant le « forming » négatif. En tenant compte du rôle important de la migration d'oxygène dans la formation / dissolution des filaments, nous discutons également des résultats obtenus par XPS avec polarisation électrique in- situ (sous ultravide) pour mieux comprendre le rôle de l'oxydation de surface et des interfaces dans la commutation résistive
Conducting bridging resistive random accessmemories (CBRAMs) are one option currently investigated for the next generation of non volatile memories. Data storage is based on switching the resistivity between high (HRS) and low (LRS) resistance states. Under electrical bias,a conductive path is assumed to be created by ions diffusion from the active electrode into the solid electrolyte. Recently, special attention has been drawn to devices containing an elemental semiconductor such as tellurium, operating with reduced currents and less retention failures. In these subquantum CBRAM cells, the filament is thought to contain tellurium , yielding a 1-atomconductance (G₁atom) significantly reduced compared to standard CBRAMs and thus allowing low power operation. In this thesis, we use X-rayphotoelectron spectroscopy (XPS) to learn about electrochemical reactions involved in the switching mechanism of Al₂O₃ based CBRAMswith ZrTe and TiTe alloys as active electrode. Two methods are used: i) non-destructive Hard X-ray photoelectron spectroscopy (HAXPES) to investigate the critical interfaces between the electrolyte (Al₂O₃) and the top and bottom electrodes and ii) Gas Cluster Ion Beams (GCIB), a sputtering technique that leads to lower structure degradation, combined with XPS depth profiling to evaluate chemical depth distributions. To FSIMS measurements are also performed to get complementary in-depth chemical information.The aim of this thesis is to clarify the driving mechanism and understand the chemical changes at both interfaces involved in the forming process under positive and negative polarization as well as the mechanism of the reset operation. For that,we performed a comparison between as-grown state, i.e. the pristine device with a formed state,i.e. the sample after the first transition between HRS and LRS, and reset state, i.e. the sample after the first transition between LRS and HRS.Conducting bridging resistive random access memories (CBRAMs) are one option currently investigated for the next generation of non-volatile memories. Data storage is based on switching the resistivity between high (HRS) and low (LRS) resistance states. Under electrical bias,a conductive path is assumed to be created byions diffusion from the active electrode into the solid electrolyte. Recently, special attention has been drawn to devices containing an elemental semiconductor such as tellurium, operating with reduced currents and less retention failures. In these subquantum CBRAM cells, the filament is thought to contain tellurium , yielding a 1-atom conductance (G₁atom) significantly reduced compared to standard CBRAMs and thus allowing low power operation. In this thesis, we use X-ray photoelectron spectroscopy (XPS) to learn about electrochemical reactions involved in the switching mechanism of Al₂O₃ based CBRAMs with ZrTe and TiTe alloys as active electrode. Twomethods are used: i) non-destructive Hard X-rayphotoelectron spectroscopy (HAXPES) toinvestigate the critical interfaces between the electrolyte (Al₂O₃) and the top and bottom electrodes and ii) Gas Cluster Ion Beams (GCIB), a sputtering technique that leads to lower structure degradation, combined with XPS depth profiling to evaluate chemical depth distributions. To FSIMS measurements are also performed to get complementary in-depth chemical information.The aim of this thesis is to clarify the driving mechanism and understand the chemical changes at both interfaces involved in the forming process under positive and negative polarization as well as the mechanism of the reset operation. For that,we performed a comparison between as-grown state, i.e. the pristine device with a formed state,i.e. the sample after the first transition between HRS and LRS, and reset state, i.e. the sample after the first transition between LRS and HRS

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Rebora, Charles. "Développement de matrices mémoires non-volatiles sur support flexible pour les circuits électroniques imprimés." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0643.

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Le marché de l’électronique flexible devrait atteindre un chiffre d’affaire de plus de 10 milliards de dollars à l’horizon 2020. La réalisation de circuits dotés de flexibilité mécanique accompagnera l’essor de nouvelles applications liées à l’internet des objets ou à l’électronique grande surface. Après la logique, la mémoire est un organe fondamental de tout système électronique. Dans cette thèse, nous nous sommes intéressés au développement de mémoires non-volatiles de type CBRAM (Conductive Bridge Random Acces Memory) pour les applications électroniques flexibles. Ces mémoires possèdent une structure MEM (Métal-Électrolyte-Métal) et font partie des mémoires non volatiles émergentes de type ReRAM (Resistive RAM). L’effet mémoire est basé sur une commutation de résistance due à des phénomènes d’oxydo-réduction et de migration ionique aboutissant à la formation/dissolution d’un filament conducteur dans l’électrolyte solide. La possibilité d’utiliser des verres de chalcogénures ou encore des polymères comme électrolytes solide offre à ces mémoires un avenir prometteur pour les applications flexibles. Après avoir passé en revue les différents matériaux exploités pour la réalisation de CBRAM, nous exposerons des travaux concernant la fabrication et la caractérisation de mémoires basées sur des électrolytes de GeS$_x$ et de Ge$_X$Sb$_Y$Te$_Z$ sur substrats de silicium. Les caractéristiques I-V obtenues (phénomènes de set et reset) sont ensuite confrontées à des simulations réalisées à l’aide d’un modèle électro-thermique qui considère le courant ionique comme facteur limitant. La dernière partie de ce travail est quant à elle dédiée au développement de mémoires flexibles
Flexible electronics market revenue is expected to exceed $10B by 2020. Duento their mechanical flexibility, flexible circuits will enable numerous developmentsnin various fields from internet-of-things applications to large area electronics. Besides logic devices, memory is the second fundamental component of any electronic system. During this thesis, we aimed at developing nonvolatile memories referred as CBRAM (Conductive-Bridge Random Access Memories) for flexible electronics applications. These devices consist in a simple Metal-Electrolyte-Metal structure. The memory effect relies on resistance switching due to the formation/dissolution of a metallic conductive filament within a solid electrolyte. The use of chalcogenide glasses or polymers layers as solid-electrolytes offers many opportunities for future for flexible applications. In a first part, memory devices based on of GeS$_x$ and de Ge$_X$Sb$_Y$Te$_Z$ solid electrolytes on silicon substrates we fabricated and electrically tested. Experimental results were then confronted to an electro-thermal model, based on ionic current, developed during this thesis. The final chapter of this manuscript is devoted to the development of flexible memories

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Liaw, Corvin [Verfasser]. "Investigation of a New Memory Technology : The Conductive Bridging Random Access Memory Technology (CBRAM) / Corvin Liaw." Aachen : Shaker, 2007. http://d-nb.info/1164339516/34.

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Longnos, Florian. "Etude et optimisation des performances électriques et de la fiabilité de mémoires résistives à pont conducteur à base de chalcogénure/Ag ou d'oxyde métallique/Cu." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT046.

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Les mémoires non-volatiles sont devenues récemment un moteur clé de la croissance du secteur des semiconducteurs, et constituent un pivot pour les nouvelles applications et les nouveaux concepts dans le domaine des technologies de l'information et de la communication (TIC). Afin de surmonter les limites en termes de miniaturisation, de consommation électrique et de complexité de fabrication des mémoires non-volatiles à grille flottante (FLASH), l'industrie des semiconducteurs évalue actuellement des solutions alternatives. Parmi celles-ci, les mémoires résistives à pont conducteur ou CBRAM (Conductive Bridge Random Access Memory), qui reposent sur la commutation de résistance d'un électrolyte par migration et oxydo/réduction d'ions métalliques, semblent être des plus prometteuses. L'attractivité de cette technologie innovante vient d'une part de la simplicité de sa structure à deux terminaux et d'autre part de ses performances électriques très prometteuses en termes de consommation électrique et vitesse d'écriture/effacement. De surcroît la CBRAM is une technology mémoire qui s'intègre facilement dans le back end of line (BEOL) du procédé CMOS standard. Dans cette thèse, nous étudions les performances électriques et la fiabilité de deux technologies CBRAM, utilisant des chalcogénures (GeS2) ou un oxyde métallique pour l'électrolyte. Tout d'abord nous nous concentrons sur les CBRAM à base de GeS2, ou l'effet du dopage de l'électrolyte avec de l'argent (Ag) ou de l'antimoine (Sb) est étudié à la lumière d'une analyse des caractérisations électriques. Les mécanismes physiques gouvernant la cinétique de commutation et la stabilité thermique sont aussi discutés sur la base de mesures électrique, d'un modèle empirique et des résultats de calculs ab initio. L'influence des différentes conditions de set/reset est étudiée sur une CBRAM à base d'oxyde métallique. Grâce à cette analyse, les conditions permettant de maximiser la fenêtre mémoire, améliorer l'endurance et minimiser la variabilité sont déterminées
Non-volatile memory technology has recently become the key driver for growth in the semiconductor business, and an enabler for new applications and concepts in the field of information and communication technologies (ICT). In order to overcome the limitations in terms of scalability, power consumption and fabrication complexity of Flash memory, semiconductor industry is currently assessing alternative solutions. Among them, Conductive Bridge Memories (CBRAM) rely on the resistance switching of a solid electrolyte induced by the migration and redox reactions of metallic ions. This technology is appealing due to its simple two-terminal structure, and its promising performances in terms of low power consumption, program/erase speed. Furthermore, the CBRAM is a memory technology that can be easily integrated with standard CMOS technology in the back end of line (BEOL). In this work we study the electrical performances and reliability of two different CBRAM technologies, specifically using chalcogenides (GeS2) and metal oxide as electrolyte. We first focus on GeS2-based CBRAM, where the effect of doping with Ag and Sb of GeS2 electrolyte is extensively investigated through electrical characterization analysis. The physical mechanisms governing the switching kinetics and the thermal stability are also addressed by means of electrical measurements, empirical model and 1st principle calculations. The influence of the different set/reset programming conditions is studied on a metal oxide based CBRAM technology. Based on this analysis, the programming conditions able to maximize the memory window, improve the endurance and minimize the variability are determined

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Guy, Jérémy. "Evaluation des performances des mémoires CBRAM (Conductive bridge memory) afin d’optimiser les empilements technologiques et les solutions d’intégration." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT127/document.

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Ces dernières décennies, la constante évolution des besoins de stockage de données a mené à un bouleversement du paysage technologique qui s’est complètement métamorphosé et réinventé. Depuis les débuts du stockage magnétique jusqu’aux plus récents dispositifs fondés sur l’électronique dit d’état solide, la densité de bits stockés continue d’augmenter vers ce qui semble du point de vue du consommateur comme des capacités de stockage et des performances infinies. Cependant, derrière chaque transition et évolution des technologies de stockage se cachent des limitations en termes de densité et performances qui nécessitent de lourds travaux de recherche afin d’être surmontées et repoussées. Ce manuscrit s’articule autour d’une technologie émergeante prometteuse ayant pour vocation de révolutionner le paysage du stockage de données : la mémoire à pont conducteur ou Conductive Bridge Random Access Memory (CBRAM). Cette technologie est fondée sur la formation et dissolution réversible d’un chemin électriquement conducteur dans un électrolyte solide. Elle offre de nombreux avantages face aux technologies actuelles tels qu’une faible consommation électrique, de très bonnes performances d’écriture et de lecture et la capacité d’être intégré aux seins des interconnexions métalliques d’une puce afin d’augmenter la densité de stockage. Malgré tout, pour que cette technologie soit compétitive certaines limitations ont besoin d’être surmontées et particulièrement sa variabilité et sa stabilité thermique qui posent encore problème. Ce manuscrit propose une compréhension physique globale du fonctionnement de la technologie CBRAM fondée sur une étude expérimentale approfondie couplée à un modèle Monte Carlo cinétique spécialement développé. Cette compréhension fait le lien entre les propriétés physiques des matériaux composant la mémoire CBRAM et ses performances (Tension et temps d’écriture et d’effacement, rétention de donnée, endurance et variabilité). Un fort accent est mis la compréhension des limites actuelle de la technologie et comment les repousser. Grâce à une optimisation des conditions d’opérations ainsi qu’à un travail d’ingénierie des dispositifs mémoire, il est démontré dans ce manuscrit une forte amélioration de la stabilité thermique ainsi que de la variabilité des états écrits et effacés
The constant evolution of the data storage needs over the last decades have led the technological landscape to completely change and reinvent itself. From the early stage of magnetic storage to the most recent solid state devices, the bit density keeps increasing toward what seems from a consumer point of view infinite storage capacity and performances. However, behind each storage technology transition stand density and performances limitations that required strong research work to overcome. This manuscript revolves around one of the promising emerging technology aiming to revolutionize data storage landscape: the Conductive Bridge Random Access Memory (CBRAM). This technology based on the reversible formation and dissolution of a conductive path in a solid electrolyte matrix offers great advantages in term of power consumption, performances, density and the possibility to be integrated in the back end of line. However, for this technology to be competitive some roadblocks still have to be overcome especially regarding the technology variability, reliability and thermal stability. This manuscript proposes a comprehensive understanding of the CBRAM operations based on experimental results and a specially developed Kinetic Monte Carlo model. This understanding creates bridges between the physical properties of the materials involved in the devices and the devices performances (Forming, SET and RESET time and voltage, retention, endurance, variability). A strong emphasis is placed on the current limitations of the technology previously stated and how to overcome these limitations. Improvement of the thermal stability and device reliability are demonstrated with optimized operating conditions and proper devices engineering

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Methapettyparambu, purushothama Jayakrishnan. "Nouvelle génération de dispositifs hyperfréquences passifs reconfigurables électroniquement basés sur la technologie de commutation CBRAM non volatile." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT086.

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Cette thèse présente une nouvelle génération de dispositifs hyperfréquences passifs, reconfigurables électroniquement, basés sur la technologie de commutation ‘Conductive Bridging Random Access Random'(CBRAM). Le travail présenté dans cette thèse a pour objectif de s’affranchir du principal inconvénient des dispositifs hyperfréquences entièrement passifs (ne nécessitant pas de batterie pour fonctionner), à savoir la reconfigurabilité électronique. En effet, sur les dispositifs radiofréquences classiques, cette fonctionnalité repose sur l'utilisation de composants de commutation plus ou moins encombrants nécessitant une puissance importante, pour être exploités, et pour maintenir un état d'impédance (PIN, MEMS et similaire). Nous proposons ici une technique permettant de reconfigurer des dispositifs passifs ne nécessitant pas d’énergie (non-volatilité) pour maintenir un état d'impédance. Cette caractéristique fondamentale distingue les commutateurs CBRAM des commutateurs RF classiques, comme indiqué ci-dessus. Nous présentons ici deux techniques pour concevoir et développer des commutateurs CBRAM potentiellement imprimables, et pouvant être intégrés dans un circuit hyperfréquence sur substrat rigide ou flexible via un procédé de fabrication simple réalisable hors salle blanche.Dans un premier temps, une preuve de concept de cette technologie est présentée à travers la réalisation expérimentale d’un commutateur RF en mode shunt sur ligne CPW réalisé sur substrat FR-4 ainsi que sur un substrat papier. Cette première étude est validée par des mesures, des simulations électromagnétiques, ainsi qu’une modélisation du commutateur sous la forme d’un circuit électrique équivalent. Ensuite, nous montrons l’intégration de ces commutateurs pour le développement d’étiquettes RFID sans puce réinscriptibles. Ces étiquettes sont similaires à un code-barres optique, mais avec une fonctionnalité améliorée de réinscriptibilité électronique et la possibilité de les lire à travers des objets opaques. Nous présentons également différentes stratégies de codage de données pour ces nouveaux tags RFID sans puce ainsi qu’une modélisation circuit pour faciliter la conception. Enfin nous montrons qu’il est possible d’intégrer ces commutateurs dans d’autres circuits micro-ondes passifs tels que des antennes reconfigurables, des filtres et des commutateurs SPDT. Ces nouveaux dispositifs sont compatibles avec des applications dont la consommation énergétique doit être faible, c’est le cas par exemple pour les capteurs sans fils autonomes en énergie appliqués à l’internet des objets (IOT) ou à la technologie 5G. Pendant toute la durée de cette thèse, nous avons œuvré pour démocratiser cette nouvelle technologie de commutation non volatile en la rendant compatible avec des procédés d’impression d’encre métallique et diélectrique, à bas coût
This thesis presents new generation of electronically reconfigurable solid-state passive microwave devices based on ‘Conductive Bridging Random Access Memory / Metal – Insulator – Metal’ (CBRAM/MIM) switching technology. The work focuses on overcoming the main drawback of fully passive (that doesn’t need any energy to operate) microwave devices, which is electronic-reconfigurability. Indeed, on conventional microwaves devices, this functionality relies on the use of bulky switching devices requiring a large power, to be operated, and to maintain an impedance state (PIN, MEMS and similar). We propose a technique to make possible to reconfigure passive devices without the requirement of constant power supply (Non-Volatility) to maintain an impedance state. This profound feature distinguishes the CBRAM/MIM switches from classic RF switches as indicated above. Here we present two techniques to design and develop fully passive non-volatile and potentially printable CBRAM/MIM switches integrated into a microwave circuit using simple fabrication steps, on rigid as well as flexible substrates. In particular without using any ‘Clean Room’ technology and with process steps compatible for mass production.The proof of concept of this technique is presented through experimental realization of a solid state CPW shunt mode RF switch on classic FR-4 and paper substrates. Equivalent electrical models and their advantages in reducing the electromagnetic simulation budget are also demonstrated affirmatively. Then we show the integration of these switches for the development of rewritable chipless RFID tags. These tags are similar to an optical barcode, but with enhanced functionality of electronic re-writeablity, and out of optical line of sight readability. Analysis of possible data encoding strategies and equivalent circuit modelling, for aiding simplified real time application design is also presented herewith. In addition we also demonstrate the application, and advantage of integration of this switching technique in devices like reconfigurable antennas, filters and SPDT switches. These devices could be used for low power stand-alone devices, ranging from low-cost sensors, to IoT and 5G applications. In this research we present our efforts to democratize this switching technology till these electronically-reconfigurable solid-state passive microwave devices could be printed using a common house-hold printer with metallic and ion-conductor inks, at an economically efficient budget

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Palma, Giorgio. "Nouvelles Architectures Hybrides : Logique / Mémoires Non-Volatiles et technologies associées." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00951384.

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Les nouvelles approches de technologies mémoires permettront une intégration dite back-end, où les cellules élémentaires de stockage seront fabriquées lors des dernières étapes de réalisation à grande échelle du circuit. Ces approches innovantes sont souvent basées sur l'utilisation de matériaux actifs présentant deux états de résistance distincts. Le passage d'un état à l'autre est contrôlé en courant ou en tension donnant lieu à une caractéristique I-V hystérétique. Nos mémoires résistives sont composées d'argent en métal électrochimiquement actif et de sulfure amorphe agissant comme électrolyte. Leur fonctionnement repose sur la formation réversible et la dissolution d'un filament conducteur. Le potentiel d'application de ces nouveaux dispositifs n'est pas limité aux mémoires ultra-haute densité mais aussi aux circuits embarqués. En empilant ces mémoires dans la troisième dimension au niveau des interconnections des circuits logiques CMOS, de nouvelles architectures hybrides et innovantes deviennent possibles. Il serait alors envisageable d'exploiter un fonctionnement à basse énergie, à haute vitesse d'écriture/lecture et de haute performance telles que l'endurance et la rétention. Dans cette thèse, en se concentrant sur les aspects de la technologie de mémoire en vue de développer de nouvelles architectures, l'introduction d'une fonctionnalité non-volatile au niveau logique est démontrée par trois circuits hybrides: commutateurs de routage non volatiles dans un Field Programmable Gate Arrays, un 6T-SRAM non volatile, et les neurones stochastiques pour un réseau neuronal. Pour améliorer les solutions existantes, les limitations de la performances des dispositifs mémoires sont identifiés et résolus avec des nouveaux empilements ou en fournissant des défauts de circuits tolérants.

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Onkaraiah, Santhosh. "Modélisation et conception de circuits à base de mémoires non-volatiles résistives innovantes." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4759.

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Les limites rencontrées par les dernières générations de mémoires Flash et DRAM (Dynamic Random Access Memory) nécessitent la recherche de nouvelles variables physiques (autres que la charge et la tension), de nouveaux dispositifs ainsi que de nouvelles architectures de circuits. Plusieurs dispositifs à résistance variable sont très prometteurs. Parmi eux, les OxRRAMs (Oxide Resistive Random Access Memory) et les CBRAMs (Conductive Bridge Random Access Memory) sont de sérieux candidats pour la prochaine génération de mémoire dense. Ce travail se concentre donc sur le rôle des mémoires résistives (OxRRAM et CBRAM) dans les mémoires embarquées et plus particulièrement dans les FPGAs. Pour cela, nous avons développé un modèle compact, outil indispensable à la conception de circuits intégrés. Ensuite, nous avons conçus de nouveaux circuits non volatiles tels que des flips-flops (NVFF), des tables de correspondance (NVLUT), des commutateurs 2x2 ainsi que des SRAMs (NVSRAM). Ces structures ont finalement été simulées dans le cas d’un FPGA, afin de vérifier l’impact de celles-ci sur la surface, le délai ainsi que la puissance. Nous avons comparé les résultats pour un FPGA à base de NVLUTs utilisant une structure 1T-2R composée de CBRAMs par rapport à un FPGA plus classique utilisant des SRAMs. Nous réduisons ainsi la taille de 5%, la consommation de 18% et améliorons la vitesse de fonctionnement de 24%. La thèse aborde la modélisation compacte, la conception des circuits, et l’évaluation de systèmes incluant des mémoires résistives
The grave challenges to future of traditional memories (flash and DRAM) at 1X nm regime has resulted in increased quest for new physical state variables (other than charge or voltage), new devices and architectures offering memory and logic functions beyond traditional transistors. Many thin film devices with resistance change phenomena have been extensively reported as ’promising candidates’. Among them, Ox- ide Resistive Memory (OxRRAM) and Conductive Bridge Resistive Memory (CBRAM) are leading contenders for the next generation high density memories. In this work, we focus on the role of Resistive Memories in embedded memories and their impact on FPGAs in particular. We begin with the discussion on the compact modeling of resistive memory devices for design enabling, we have designed novel circuits of non- volatile flip-flop (NVFF), non-volatile look-up table (NVLUT), non-volatile 2x2 switch and non-volatile SRAM (NVSRAM) using Resistive Memories. We simulated the impact of these design structures on the FPGA system assessing the performance parameters of area, delay and power. By using the novel 1T-2R memory element concept of CBRAMs in FPGAs to implement Look-up Tables (NVLUT), we would scale down the area impact by 5%, enhance speed by 24% and reduce the power by 18% compared to SRAM based FPGAs. The thesis addresses aspects of compact modeling, circuit design and system evaluation using resistive memories

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Barci, Marinela. "Caractérisation électrique et optimisation technologique des mémoires résistives Conductive Bridge Memory (CBRAM) afin d’optimiser la performance, la vitesse et la fiabilité." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT022/document.

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La technologie Flash arrive à ses limites de miniaturisation. Ainsi, la nécessité de nouvelles technologies mémoire augmente. Les candidats au remplacement des mémoires Flash sont les technologies non volatiles émergentes comme les mémoires à pont conducteur (CBRAM), résistives à base d'oxyde (RRAM), mémoires magnétiques (MRAM) et mémoires à changement de phase (PCRAM). En particulier, les mémoires CBRAM sont basées sur structure simple métal-isolant-métal (MIM) et présentent plusieurs avantages par rapport aux autres technologies. La CBRAM est non volatile, à savoir qu'elle garde l’information lorsque l'alimentation est coupée, ses dimensions peuvent être réduites jusqu'à nœud 10 nm, elle peut facilement être intégrée dans le Back-End d’une intégration CMOS, enfin, elle a une vitesse de fonctionnement élevée à basse tension et un faible coût de fabrication. Néanmoins, les spécifications pour l'industrialisation des CBRAM sont très strictes. Dans cette thèse, nous analysons deux générations de technologie CBRAM, chacune adressant un marché d'application spécifique. La première partie de la thèse est consacrée à l’étude électrique des structures à base de cuivre et de GdOX, qui présentent comme avantages une conservation des données très stable et une bonne résistance lors de la soudure des puces, et un bon comportement de l'endurance. Cette technologie adresse principalement les applications à haute température telle que l'automobile. Pour répondre aux spécifications, un oxyde métallique dopé ainsi que des bicouches sont intégrés pour réduire la tension de formation de la mémoire et augmenter la fenêtre de programmation. Les performances en endurance sont améliorées. La deuxième partie est dédiée à une nouvelle technologie de CBRAM, avec un empilement de type MIM. Dans ce cas, nous avons démontré des temps de commutation très rapides de 20ns à basses tensions (2V), combinés avec une endurance satisfaisante et une bonne rétention des données. Cette technologie semble être compatible avec les applications Internet des objets (IOT). En résumé, au cours de ce doctorat, l'objectif principal était d'étudier la fiabilité des dispositifs embarqués CBRAM en termes d’écriture des données, endurance et la conservation de l’information. Une méthodologie de test spécifique a été développée, afin d’évaluer les performances des technologies étudiées. Des modèles physiques ont été mis au point pour expliquer et analyser les résultats expérimentaux. Sur la base des résultats obtenus, nous démontrons que la technologie de CBRAM est très prometteuse pour les futures applications de mémoires non volatiles
Flash technology is approaching its scaling limits, so the demand for novel memory technologies is increasing. Promising replacing candidates are the emerging non volatile technologies such as Conductive Bridge Memory (CBRAM), Oxide based Resistive RAM (OXRAM), Magnetic Random Access Memory (MRAM) and Phase Change Memory (PCRAM). In particular, CBRAM is based on a simple Metal-Insulator-Metal (MIM) structure and presents several advantages compared to the other technologies. CBRAM is non volatile, i.e. it keeps the information when the power is off, it is scalable down to 10nm technology node, it can be easily integrated into the Back-End-of-Line (BEOL), finally, it has high operation speed at low voltages and low cost per bit. Nevertheless, demands for the industrialization of CBRAM are very stringent and issues related to device reliability are still to be faced. In this thesis we analyze two generations of CBRAM technology, each one addressing a specific application market. The first part of the PhD is dedicated to the electricalstudy of Cu-based/GdOx structures, which present the advantages of a very stable data retention and resistance to soldering reflow and also good endurance behavior. This CBRAM family addresses mainly the high temperature applications as automotive. To fulfill the specification requirements, doping of metal-oxide andbilayers are integrated to decrease the forming voltage and increase the programmingwindow. Better endurance performance is also achieved. The second part isdedicated to a new CBRAM technology, with a simple MIM structure. In this case, the device showsfast operation speed of 20ns at low voltages of 2V, combined with satisfying endurance and data retention. This technology seems to be compatible with the growing Internet of Things (IOT) market. In summary, during the PhD research, the main objective was to study the reliability of the embedded CBRAM devices in terms of forming, endurance and data retention. Some methodologies were developed and the electrical set-up was modified and adapted to specific measurements. Physical models were developed to explain and better fit the experimental results. Based on the obtained results, we demonstrate that the CBRAM technology is highly promising for future NVM applications

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Ali, Rizwan. "Resistive Switching in Porous Low-k Dielectrics." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83462.

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Integrating nanometer-sized pores into low-k ILD films is one of the approaches to lower the RC signal delay and thus help sustain the continued scaling of microelectronic devices. While increasing porosity of porous dielectrics lowers the dielectric constant (k), it also creates many reliability and implementation issues. One of the problems is the little understood metal ion diffusion and drift in porous media. Here, we present a rigorous simulation method of Cu diffusion based on Master equation with elementary jump probabilities within the contiguous dielectric film, along the pore boundary, from the dielectric matrix to the pore boundary, and from the pore boundary to the matrix material. In view of the diffusional jump distance being as large as 2 nm, the nano-pores being on a similar length scale, and the film thickness being only a few tens of nanometers, the conventional diffusion equation in differential equation form is grossly inadequate and elementary jump frequencies are required for a proper description of the Cu diffusion in porous dielectric. The present atomistic approach allows a consistent implementation of Cu ion drift in electric field by lowering and raising of the diffusion barriers along the field direction. This will help understand the behavior of Cu interconnects under thermal or electric stress at an atomistic level. Another approach to lower the increasing RC delays is to bring memory and logic closer by integrating memory in the BEOL. Resistive RAM is one such memory is not transistor based and thus, does not require a silicon substrate. Thus, it offers the possibility of integration directly into the back-end reducing memory to logic distance from 1000s of µm to a 10s of nm. This 3D integration also allows for increased density as well. However, one barrier in the implementation of RRAM in the back end is the use of expensive as well as non-BEOL native material in conventional Cu/TaOx/Pt resistive devices. In this thesis, we present our research about functionality of RRAM with porous low-k dielectrics (which are a candidate for CMOS ILD), and through the similar elementary jump simulations, discuss the impact of porosity in dielectrics on the functionality of RRAM. Lastly, we present a cheaper replacement for Pt as the counter electrode in RRAM and show that it functions as good as Pt. This work addresses following three areas: 1. Modeling of diffusion in porous dielectrics through elementary jump based simulation. The model is based on random walk theory of elementary particle jumps. Initially, qualitative simulations are conducted without actual parameters. It is shown that Cu diffusion in porous dielectrics decreases quasi-linearly with porosity. Furthermore, it is shown that morphology of the pores may have a greater effect on diffusivity compared to porosity. The simulations are then calibrated with parameters, and the result is shown to yield a similar diffusivity times as actual process time. 2. Modeling of Cu ions drift in porous dielectrics under electric stress. First, the model is explained, and then qualitative simulation results are presented for porous dielectrics with varied porosities and morphologies. 3. Research to find a suitable replacement for Pt as the counter electrode in RRAM devices. The research methodology is discussed and a much cheaper Rh is selected as the potential replacement for Pt. Successful functionality of Rh based resistive devices is presented.
Master of Science

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Prasai, Kiran. "Gap Engineering and Simulation of Advanced Materials." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1503393620371266.

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Rebora, Charles. "Développement de matrices mémoires non-volatiles sur support flexible pour les circuits électroniques imprimés." Electronic Thesis or Diss., Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0643.

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Le marché de l’électronique flexible devrait atteindre un chiffre d’affaire de plus de 10 milliards de dollars à l’horizon 2020. La réalisation de circuits dotés de flexibilité mécanique accompagnera l’essor de nouvelles applications liées à l’internet des objets ou à l’électronique grande surface. Après la logique, la mémoire est un organe fondamental de tout système électronique. Dans cette thèse, nous nous sommes intéressés au développement de mémoires non-volatiles de type CBRAM (Conductive Bridge Random Acces Memory) pour les applications électroniques flexibles. Ces mémoires possèdent une structure MEM (Métal-Électrolyte-Métal) et font partie des mémoires non volatiles émergentes de type ReRAM (Resistive RAM). L’effet mémoire est basé sur une commutation de résistance due à des phénomènes d’oxydo-réduction et de migration ionique aboutissant à la formation/dissolution d’un filament conducteur dans l’électrolyte solide. La possibilité d’utiliser des verres de chalcogénures ou encore des polymères comme électrolytes solide offre à ces mémoires un avenir prometteur pour les applications flexibles. Après avoir passé en revue les différents matériaux exploités pour la réalisation de CBRAM, nous exposerons des travaux concernant la fabrication et la caractérisation de mémoires basées sur des électrolytes de GeS(x) et de Ge(x)Sb(y)Te(z) sur substrats de silicium. Les caractéristiques I-V obtenues (phénomènes de set et reset) sont ensuite confrontées à des simulations réalisées à l’aide d’un modèle électro-thermique qui considère le courant ionique comme facteur limitant. La dernière partie de ce travail est quant à elle dédiée au développement de mémoires flexibles
Flexible electronics market revenue is expected to exceed 10B dollars by 2020. Duento their mechanical flexibility, flexible circuits will enable numerous developmentsnin various fields from internet-of-things applications to large area electronics. Besides logic devices, memory is the second fundamental component of any electronic system. During this thesis, we aimed at developing nonvolatile memories referred as CBRAM (Conductive-Bridge Random Access Memories) for flexible electronics applications. These devices consist in a simple Metal-Electrolyte-Metal structure. The memory effect relies on resistance switching due to the formation/dissolution of a metallic conductive filament within a solid electrolyte. The use of chalcogenide glasses or polymers layers as solid-electrolytes offers many opportunities for future for flexible applications. In a first part, memory devices based on of GeS(X) and de Ge(X)Sb(Y)Te(Z) solid electrolytes on silicon substrates we fabricated and electrically tested. Experimental results were then confronted to an electro-thermal model, based on ionic current, developed during this thesis. The final chapter of this manuscript is devoted to the development of flexible memories

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Sundararajan, Mayur. "Amorphous Semiconductors: From Photocatalyst to Computer Memory." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1490967991624172.

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Mahato, Prabir. "Study and development of resistive memories for flexible electronic applications." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI134.

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L’avènement de l’électronique flexible a entraîné des recherches rapides sur des capteurs, des dispositifs bio-implantables et portables pour l’évaluation de maladies telles que l’épilepsie, la maladie de Parkinson et les crises cardiaques. Les dispositifs de mémoire sont des composants majeurs dans tous les circuits électroniques, uniquement secondaires aux transistors, par conséquent de nombreux efforts de recherche sont consacrés au développement de dispositifs de mémoire flexibles. Les mémoires à accès aléatoire à pont conducteur (CBRAM) basées sur la création / dissolution d'un filament métallique dans un électrolyte solide sont d'un grand intérêt pour la recherche en raison de leur architecture métallique isolante métallique simple, de leurs capacités basse tension et de leur compatibilité avec les substrats flexibles. Dans ce travail, au lieu d'un oxyde métallique conventionnel ou d'une couche de chalcogénure, un polymère biocompatible - l'oxyde de polyéthylène (PEO) - est utilisé comme couche d'électrolyte solide en utilisant l'eau comme solvant. Des dispositifs de mémoire, constitués d'empilements tri-couches Ag / PEO / Pt, ont été fabriqués à la fois sur du silicium et des substrats flexibles en utilisant un processus hétérogène combinant un dépôt physique en phase vapeur et un revêtement par rotation. Pour cela, une étude systématique de l'effet de la concentration de la solution et de la vitesse de dépôt sur l'épaisseur du PEO est présentée. Des mesures SEM / EDX et AFM ont ensuite été effectuées sur des structures planes dédiées à «nano-gap» et ont révélé la formation de précipités métalliques d'Ag ainsi que des changements morphologiques de la couche de polymère après commutation de résistance. Les performances des dispositifs de mémoire résistive sont ensuite évaluées sur silicium et substrats flexibles. En particulier, la programmation des statistiques de tension, le rapport de résistance OFF / ON, les cycles d'endurance et les tests de rétention sont effectués et l'effet de la conformité du courant est analysé. Le mécanisme de conduction dans le HRS / LRS est étudié sur les appareils de référence Ag / PEO / Pt et Pt / PEO / Pt. Enfin, la caractérisation électrique des dispositifs sur substrat souple est réalisée sous contrainte mécanique, donnant des résultats prometteurs. Les dispositifs CBRAM à base de polymères sont donc proposés comme candidats potentiels pour le développement durable de dispositifs de mémoire flexibles
The advent of flexible electronics has brought about rapid research towards sensors, bio implantable and wearable devices for assessment of diseases such as epilepsy, Parkinson’s and heart attacks. Memory devices are major component in any electronic circuits, only secondary to transistors, therefore many research efforts are devoted to the development of flexible memory devices. Conductive Bridge Random Access Memories (CBRAMs) based on creation/dissolution of a metallic filament within a solid electrolyte are of great research interest because of their simple Metal Insulator Metal architecture, low-voltage capabilities, and compatibility with flexible substrates. In this work, instead of a conventional metallic oxide or a chalcogenide layer, a biocompatible polymer - Polyethylene Oxide (PEO) – is employed as the solid electrolyte layer using water as solvent. Memory devices, consisting in Ag/PEO/Pt tri-layer stacks, were fabricated on both silicon and flexible substrates using a heterogeneous process combining physical vapour deposition and spin coating. To aim this, a systematic study on the effect of solution concentration and deposition speed on the PEO thickness is presented. SEM/EDX and AFM measurements were then conducted on devoted “nano-gap” planar structures and have revealed the formation of metallic Ag precipitates together with morphological changes of the polymer layer after resistance switching. The performance of the resistive memory devices is then assessed on silicon and flexible substrates. In particular programming voltage statistics, OFF/ON resistance ratio, endurance cycles and retention tests are performed and the effect of current compliance is analysed. The conduction mechanism in the HRS/LRS is studied on the Ag/PEO/Pt and Pt/PEO/Pt reference devices. Finally, the electrical characterization of devices on flexible substrate is performed under mechanical stress, showing promising results. Polymer-based CBRAM devices are therefore suggested as potential candidates for sustainable development of flexible memory devices

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Cardoza, Yanet. "An Exploration of Teachers' Adoption of the Bring Your Own Technology Program." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc283863/.

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The purpose of this study was to explore teachers' concerns, use, and actual practices in their adoption of the bring your own technology (BYOT) initiative. Twelve secondary teachers in a private school setting participated in this study. The participants represented all content areas including reading, math, science, and electives. The private school was in its third year of implementing BYOT. This case study incorporated multiple methods to collect data to gain a better understanding of teachers' adoption of an innovation, BYOT. The concerns-based adoption model (CBAM) was used as a theoretical framework. All three CBAM tools provided data: the Stages of Concern Questionnaire (SoCQ), levels of use interview protocol (LoUIP), and the innovation configuration (IC) map. Twelve of the participants completed the SoCQ across three different points in time. Six of the twelve teachers participated in three one-on-one interviews, including the LoUIP. Additionally, six teachers were observed in their classrooms during instruction. After triangulating all pieces of data, the majority of teachers had highest concerns related to self. Teachers were concerned about their ability to implement the innovation and managing BYOT in their classroom. Four of the six teachers had a level of use (LoU) at mechanical, and two teachers had a LoU at routine. The teachers' LoU indicated that they are using BYOT in the classroom; however, the majority of teachers observed had adoption practices mostly in the non-ideal variations of IC. The teachers' LoU and IC indicated that teachers had implemented BYOT in their own way and not necessarily in alignment with the campus' vision or expectations. This case study had several limitations, including the small number of participants and the brevity of classroom observations. Additionally, this study was limited to one school setting. Recommendations for future research include exploring teachers' adoption of BYOT in various school settings (i.e., both public and private schools) and teachers at the elementary, middle, and high school levels. Researchers should consider exploring the impact of specific interventions and support on teachers' adoption.

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Suri, Manan. "Technologies émergentes de mémoire résistive pour les systèmes et application neuromorphique." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00935190.

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La recherche dans le domaine de l'informatique neuro-inspirée suscite beaucoup d'intérêt depuis quelques années. Avec des applications potentielles dans des domaines tels que le traitement de données à grande échelle, la robotique ou encore les systèmes autonomes intelligents pour ne citer qu'eux, des paradigmes de calcul bio-inspirés sont étudies pour la prochaine génération solutions informatiques (post-Moore, non-Von Neumann) ultra-basse consommation. Dans ce travail, nous discutons les rôles que les différentes technologies de mémoire résistive non-volatiles émergentes (RRAM), notamment (i) Phase Change Memory (PCM), (ii) Conductive-Bridge Memory (CBRAM) et de la mémoire basée sur une structure Metal-Oxide (OXRAM) peuvent jouer dans des dispositifs neuromorphiques dédies. Nous nous concentrons sur l'émulation des effets de plasticité synaptique comme la potentialisation à long terme (Long Term Potentiation, LTP), la dépression à long terme (Long Term Depression, LTD) et la théorie STDP (Spike-Timing Dependent Plasticity) avec des synapses RRAM. Nous avons développé à la fois de nouvelles architectures de faiblement énergivore, des méthodologies de programmation ainsi que des règles d'apprentissages simplifiées inspirées de la théorie STDP spécifiquement optimisées pour certaines technologies RRAM. Nous montrons l'implémentation de systèmes neuromorphiques a grande échelle et efficace énergétiquement selon deux approches différentes: (i) des synapses multi-niveaux déterministes et (ii) des synapses stochastiques binaires. Des prototypes d'applications telles que l'extraction de schéma visuel et auditif complexe sont également montres en utilisant des réseaux de neurones impulsionnels (Feed-forward Spiking Neural Network, SNN). Nous introduisons également une nouvelle méthodologie pour concevoir des neurones stochastiques très compacts qui exploitent les caractéristiques physiques intrinsèques des appareils CBRAM.

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Mayfield, Melissa J. "Instructional Coaching in a Small District: A Mixed Methods Study of Teachers' Concerns." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955060/.

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This study utilized a convergent parallel mixed methods design to study teachers' concerns during implementation of instructional coaching for math in a rural PK-12 district in north Texas over a three-year time period. Five campuses were included in the study: one high school (grades 9-12), one middle school (grades 6-8), and three elementary campuses (pre-kindergarten through grade 5). In a school district of 3,400 students and 241 teachers, fifty-two math teachers were surveyed and interviewed for their perceptions and concerns during implementation of instructional math coaching in order to assist central office administration in knowing how to support teachers through the change process. Data included the Stages of Concern Questionnaire (SoCQ) at three points during the study period analyzed through nonparametric statistical analysis. No statistically significant differences were found to exist between campuses. However, a statistically significant difference was found when campuses were grouped by elementary and secondary campuses. Open-Ended Statements of Concern and focus group interview data by campus served as qualitative data to triangulate concerns and to measure situational evidence of rurality influence on teachers' concerns. Convergence of qualitative and quantitative findings indicate concerns clustered in unconcerned, informational, and personal stages. Evidence of rural contextual influences point to limited resources and dense staff relationships in rural schools. This data aids the district under study in supporting teachers through the process of change as an instructional coaching program for math is implemented systemically.

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Hu, Xuanlu. "ICT Integration in the New Arts Curriculum: Queensland Music Teachers' Perceptions." Thesis, Griffith University, 2017. http://hdl.handle.net/10072/370436.

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The aim of this research is to understand Queensland secondary school music teachers’ beliefs about technology integration and the Information and Communication Technology (ICT) component in the recently introduced Australian Curriculum: The Arts-Music. Previous research on technology integration indicated that many teachers might be reluctant to use technology resources in music teaching or have misunderstandings about technology integration. Moreover, some studies assumed many music teachers have negative attitudes towards the Australian Curriculum. It is imperative to understand teachers' beliefs and identify the significant barriers of technology integration in order to effectively implement the Australian Curriculum. This research employs qualitative case study method and uses Inductive Thematic Analysis to determine the significant factors that influence teachers' beliefs. Six teachers participated in one-to-one semi-structured interviews. Findings show teachers generally have high level understandings about technology integration according to the Stages of Concerns descriptions in the Concerns Based Adoption Model (CBAM); Teachers provided positive responses about the curriculum, but they showed no immediate intention to implement the curriculum. Teachers also reported technology integration barriers including financial limitation, insufficient learning opportunities, and lacking institutional support. The discussion argues that the teachers are yet to be familiar with the curriculum, and the reasons include a lack of school administration’s support, and teachers are considering a practical implementation plan. It is also difficult for many schools to substantially change the existing music programs without significant demands or advantages. The research analysed the barriers to future technology integration and found insufficient leadership and technical support are important first-order barriers. More importantly, teachers’ beliefs about technology integration are closely associated with their previous study experience and the quality of current professional development opportunities. Recommendations are provided for teachers, school leaders, and curriculum agencies including taking a teacher self-assessment of ICT learning needs, providing on-demand professional development opportunities and institutional support, and offering guidance for curriculum implementation.
Thesis (Masters)
Master of Education and Professional Studies Research (MEdProfStRes)
School Educ & Professional St
Arts, Education and Law
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Hwu, Shih-Hsung. "Concerns and professional development needs of university faculty in adopting online learning." Diss., Kansas State University, 2011. http://hdl.handle.net/2097/13129.

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Doctor of Philosophy
Curriculum and Instruction
Rosemary Talab
The purpose of this mixed methods study was to explore concerns and professional development needs of faculty at the University Alaska Fairbanks (UAF) on the adoption of online learning (OL). This study was also in response to Title 24 of the Alaska Statute’s Recommendation #3, which required sufficient faculty training in distance education technologies for teaching UAF distance courses. This study utilized the Concerns Based Adoption Model (CBAM) as its theoretical framework. A mixed methods design was used to address the research questions. Both quantitative and qualitative methods were used to collect and analyze data. A non-experimental, cross-sectional survey design was used, incorporating the Stages of Concern Questionnaire (SoCQ). Quantitative measures included surveys were sent out to 253 UAF faculty. Ninety-six surveys were returned and usable, with a final response rate of 39%. MANOVA analyses were used to identify potential variables predictive of faculty member’s concerns and professional development needs regarding the implementation of OL. Qualitative measures included three open-ended questions and sixteen faculty interviews, chosen through stratified sampling. The Stages of Concern Questionnaire indicated that the majority of UAF faculty members displayed a typical SoCQ “nonuser” profile in adopting OL. Faculty’s highest concerns were unrelated, self, and task concerns, with a slight tailing-up of impact-refocusing concerns, indicating resistance to OL. Individual variables found to potentially be predictive of faculty members’ concerns included years of teaching experience, administrative support of technology and academic rank. Qualitative measures revealed that overall themes were administrative support, including workload consideration and tenure recognition. Professional development needs included current technology and LMS (Blackboard) workshops. At the same time, faculty voiced their concerns about OL through the themes of instructional quality and support (technical assistance and equipment) concerns. Several faculty members also stated that they needed no support and their resistance of OL. Recommendations for UAF included holistic approach to administrative support, proper recognition of achievements OL achievements, promotion of learner-centered methodology in the transition to OL, professional development that lead to a more collaborative community, an enhanced role for centralized support for staff engaged in OL and LMS training. Recommendations for future studies included further qualitative studies to elucidate faculty concerns within the University of Alaska system. A national study was recommended to help faculty and administrators create better university OL policies and discover mutual expectations of how teaching and developing OL courses could be viewed as part of a new approach to workload considerations in a changing university climate, including the tenure and promotion process.

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Omar, Saud. "Concerns and professional development needs of faculty at King Saud University in Saudi Arabia in adopting online teaching." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32853.

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Doctor of Philosophy
Curriculum and Instruction Programs
Rosemary S. Talab
With the number of students at King Saud University exceeding 60,000, the university faces a need to adopt online teaching. The purpose of this study was to investigate the concerns of the faculty in the nine departments of the College of Education at King Saud University regarding the adoption of online teaching and to relate their concerns to their professional development needs. The Concerns-Based Adoption Model (CBAM) was utilized as a theoretical framework, and a non-experimental, cross-sectional survey design was used to collect the data. The data were obtained from 296 faculty members, which was a response rate of 66%. Respondents’ stages of concern 0-2 (Unconcerned, Informational, and Personal) were the highest, while stages 4-6 (Consequence, Collaboration, and Refocusing) were the lowest. The highest stage of concern was stage zero (Unconcerned), with a 96% percentile score. This indicated that respondents had little concern about or involvement with online teaching. The second highest stage score was stage one (Informational), with a 90% percentile score. This indicated that the respondents wanted more information about online teaching. Additionally, stage six (Refocusing) tailed up 15 percentile points, which indicated that respondents might be resistant to online teaching. A one-way MANOVA test result (p = .047) revealed a statistically significant difference between respondents' age and respondents' concerns in adopting online teaching. The statistical significance differences were found in stage zero (Unconcerned) (p = .041) and stage six (Refocusing) (p = .018). Another one-way MANOVA test results (p = .004) showed a statistically significant difference between respondents' gender and respondents' concerns in adopting online teaching. The statistically significance differences were found in stage zero (Unconcerned) (p = .035) and stage three (Management) (p = .001). t-test results indicated that female participants had a higher concern on both stages than male participants. Additional one-way MANOVA test results (p = .004) also indicated a statistically significant difference on the participants' concerns when adopting online teaching based on their department association. The significance value was found in stage three (Management) (p = .005). Another one-way MANOVA test showed a statistically significant difference on the concern based on the academic rank (p=.053). The significance values were found in stage one (Informational) (p = .001), stage two (Personal) (p = .002), and stage three (Management) (p = .002). Finally, three MANOVA tests indicated statistically significant differences: First, on participants' use of technology in teaching based on their prior instructional technology use (p = .017); second, on participants' use of technology in teaching based on their perception of technology-related professional development needs (p=.031); third, on participants' use of technology in teaching based on their attitudes toward online teaching (p=.004) and (p=.002). The study concluded with recommendations for future studies and for King Saud University regarding designing and implementing training programs to improve the faculty adoption of online teaching.

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Isbell, Laura J. "Secondary Teachers’ Concerns about Response to Intervention: Using the Concerns-Based Adoption Model." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc271832/.

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This case study addressed the problem of implementing response to intervention (RTI) in general secondary education. To investigate this problem, one north Texas school's RTI implementation was examined using the theoretical framework of the concerns-based adoption model (CBAM) and defining RTI as the innovation. RTI-related practices were studied for 10 secondary teachers, two from each core subject (i.e., mathematics, English language arts, science, and social studies) and the fine arts who had been implementing RTI for several years. Data regarding participants' stages of concern about and levels of use of RTI were collected across three time intervals using the three diagnostic instruments of CBAM (i.e., Stages of Concern Questionnaire, Levels of Use interviews, and Innovation Configuration Checklist matrix), behavioral observations during instruction and RTI meetings, and structured exit interviews of participants. Overall, findings indicated that the secondary teachers were at similar stages of concern and levels of use of RTI. Teachers' RTI concerns scores remained highest in the Self phase and lowest in the Impact phase of concern at all three intervals of data collection. As levels of RTI use increased, observed RTI use increased; however, teachers' RTI levels of use scores remained in the early levels of RTI implementation at all three intervals of data collection. Patterns in teachers' responses during exit interviews suggested that contextual factors unique to this setting (e.g., unexpected changes in RTI protocol, priorities of administrative personnel, and demands placed on teachers) may have influenced teachers' concerns about the teacher's role in, the professional development in, and the sustainability of RTI as an innovation. The literature does not currently address secondary teachers' concerns about and levels of use of RTI in relation to CBAM. Therefore, this study not only fills a gap in literature but also has implications for how teachers are trained and supported in implementing and sustaining the practices of consultation and differentiated instruction associated with RTI. This case study provided insight about the importance and value of teachers' participation and knowledge of RTI to facilitate the change process successfully.

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Chia, Steven Puay Chong. "An investigation into student and teacher perceptions of, and attitudes towards, the use of information communications technologies to support digital forms of summative performance assessment in the applied information technology and engineering studies courses in Western Australia." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1806.

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This study investigated the connections between teachers’ and students’ perceptions of, and attitudes towards, the use of Information and Communications Technologies (ICT) to support assessment in senior secondary courses in Western Australia, and the feasibility of such support in various forms. This investigation focused on the main characteristics of these perceptions, and attitudes and their relationships with curriculum, pedagogy, assessment and ICT. The findings provide guidelines for educators in using ICT to support summative performance assessment. My study was part of the main research study undertaken by Edith Cowan University (ECU) and the Curriculum Council of Western Australia (CCWA) and will provides significant clarity into the implementation of ICT support for performance assessment employing practices which characterise practical performance in digital forms. It was in the range of teacher and student perceptions and attitudes that this study added knowledge to the practice of digital forms of assessment. The overall intent was to design, cultivate and implement the best assessment task possible to measure the practical performance of students in Engineering Studies and Applied Information Technology (AIT). Therefore, it was also necessary to evaluate the feasibility of this task and factors that would affect feasibility such as perceptions and attitudes of particpants. To achieve this the study needed to gather data in various forms from a wide variety of sources that would allow triangluation of data analysis. Qualitative data were gathered from a student survey where a set of measurements scales were constructed. Quantitative data were assembled from observation and discussion with teachers before, during and after schools’ visits, from open-ended items in the student survey section and from teacher interview responses. In addition small groups of students were assembled into discussion forums and responses to a series of questions were recorded and analysed. A number of critical thresholds had been reached to underpin the relevance and importance of research into aspects of the use of ICT to support summative assessment. Firstly the growth in access to, and improvements, in ICT services has enabled this emergent area of digital assessment or e-assessment (JISC, 2006). However, this growth is not sufficient justification for the investigation and implementation of digital forms of assessment. The research is justified when this growth in ICT is combined with the increasing use of ICT to improve pedagogical practices; the employment of ICT to improve productivity in education; and the need to effectively and efficiently assess the practical performance of students in a large number of contexts. It was likely that the development of techniques to represent student performance in digital forms would assist the addressing of these imperatives. Whether these techniques were successful would depend on a number of influences including the attitudes and perceptions of students and teachers. When accountability and efficiency are called upon comparisions are often made with non-ICT strategies. These controlled experiment approaches can prove problematic due to ethical and political questions arising with non-ICT groups. The inherent assumptions to computer use in exams contexts are still conducted using pen and paper. In addition their lack of or slow uptake of ICT and the believed that curriculum will remain unchanged despite the introduction of ICT to support. Therefore this study took an ethnographic, rather than experimental approach, but sought to make comparisons between two key stakeholders; teachers and students. In line with the larger study of which this study was a part, data were collected using observation, interview, survey and document analysis. Analysis and interpretation included the application of a feasibility framework and case study comparison. The adoption of the Concerns Based Adoption Model (CBAM) or models based upon CBAM as an instrument to analyse data was employed in the case studies. The feasibility framework comprised four interrelated and complex parameters Manageability, Technical, Functional and Pedgogical dimensions is described in chapter eight of this study. It was evident from the research data, that students’ and teachers’ positive attutudes towards the computer-based performance exams and their beliefs in the value of ICT for assessment and all these intrinsic factors were fundamental to the feasibility of the implementation of digital forms of assessment in both Engineering Studies and AIT. From research data it was evident the application of ICT increasingly permeates students’ and teachers’ work and life, and their attitudes towards interaction with computer systems was a major factor in the success of digital forms of assessments in practical performance tasks. This was the focus and the background for this study. This study found that students in both the Engineering studies and AIT case studies attempted the assessment tasks with enthusiasm, however the AIT assessments were perceived a little more positively by students and teachers than the Engineering studies assessment. Assessment tasks worked best where the approach was familiar to students. This occurred for almost all cases in AIT, but not for Engineering although approach was relatively similar there were logisitical constraints in organising time to complete the tasks and in some cases technical in running the software on school workstations or accessing online systems through school networks. In a number of schools changes had to be mads to standard operating systems to allow software to run off USB thumb drives, video to be viewed, Flash applications to run within Internet browsers and sound to be recorded. Overall the study found that the benefits of digital forms of assessment implemented outweighted the constraints for both the Engineering studies and AIT course. In particular students’ and teachers’ responses were overwhelmingly postive due to the practical nature of the work in all assessment tasks. Generally they perferred this form of assessment to paper-based assessments. This study has added to existing knowledge on the implementing of digital forms of assessment, in particular to both the Engineering Studies and AIT, and in general to secondary senior courses in Western Australian (WA) schools.

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Doughney, John F. "The relationship of teacher efficacy to teacher concerns and job-embedded professional development." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9107/.

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As educators search for ways of improving student achievement, it is imperative that focus be placed on teacher learning and development. Currently, the trend in public schools throughout the country is to look directly at students and the deficits they bring to the learning environment when responding to those who find fault with the educational system. The current study directed attention to teachers' beliefs about their ability to affect change in student learning. The study centered on seven research questions that sought to determine: (1) the effect of job-embedded staff development on teachers' sense of efficacy; (2) the effect of job-embedded staff development on teachers' stages of concern; (3) the relationship between teacher efficacy and stages of concern; (4) the status of teachers' level of use of an innovation; and (5) the dominance of teacher concerns prior to and after involvement in job-embedded professional development. Through a mixed methodology approach, quantitative and qualitative analyses provided perspectives from 30 teachers in a suburban North Texas school district on the impact of job-embedded professional development on teacher efficacy, stages of concern, and resulting levels of use of an educational innovation. Quantitative results of two surveys: the Teacher Sense of Efficacy Scale (Tschannen-Moran & Woolfolk Hoy, 2001) and the Stages of Concern Questionnaire (Hall, George, & Rutherford, 1979) revealed a strong focus on stage 0, awareness, concerns and no statistically significant gain in teacher efficacy as teachers engaged in job-embedded professional learning. Qualitative data were gathered through Levels of Use Focused Interviews (Loucks, Newlove, & Hall, 1975) and revealed more teacher involvement with the innovation than quantitative data suggested. Further investigation into the inconsistencies between dominance of teacher concerns and perceptions of levels of use is warranted.

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27

Giorgobiani, Ioseb. "Optimální modelování nýtového spoje pomocí metody konečných prvků." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417911.

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Diplomová práce je zaměřena na optimální modelování nýtového spoje pro tři různé konfigurace pomocí metody konečných prvků v programu MSC. Nastran/Patran. Na základě prezentovaných výsledků je možné virtuálně simulovat chování nýtových spojů při zatížení, za účelem správného návrhu před provedením statických pevnostních zkoušek. Použitím těchto MKP simulací v procesu certifikace výrobku lze významně redukovat časovou i finanční náročnost pevnostních zkoušek. Při lepším porozumění chování konstrukce lze také lépe predikovat reálnou únosnost nýtových spojů.

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Fields, Melanie. "Transfer From a UTeach Replication Site to the Classroom: A Study of First and Second Year Instructional Practices." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc799531/.

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Concerns based adoption model (CBAM) instruments were used to examine instructional practices of six graduates from a highly stylized, inquiry-based secondary math and science preparation program. Teachers were in the first or second years of teaching mathematics in six different secondary settings, ranging from poverty to wealthy schools. CBAM assumptions were tested. The primary assumption about concerns was that new teachers’ highest concerns would be within the self and task dimensions. According to Hall and Hord, it was assumed that the levels of use are typically in the orientation and preparation stages as a new teacher begins to implement an innovation, in the case of this study, inquiry-based instruction. All three instruments of the CBAM model were used for data collection and included: the Survey of Concerns Questionnaire, Innovation Components Configuration Map, and Levels of Use matrix. Teachers were observed, interviewed, and surveyed, three times each, across a five-month period. The findings from this study showed that the teachers had similar concerns and levels of use, which supported the assumptions outlined by the CBAM principles. Across the six teachers, the self and task concerns were high, aligning with the assumptions. However, unrelated and impact dimensions were noted, in opposition to the assumption. Likewise, assumptions of the levels of use were upheld in the orientation and preparation levels of use noted in the observations. Some mechanical levels of use were observed for a few of the teachers, an anomaly to the assumption.

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29

Pepe, Theresa Marie. "Teacher Perceptions and Attitudes of Classroom Technology Integration Related to iPad Training." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/1913.

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While professional development on the use of technology in the classroom aids educators to implement new teaching strategies, little is known about teachers' concerns with professional development specifically for adopting mobile technologies like iPads in their classrooms. The purpose of this study was to discover teachers' attitudes and perceptions toward teacher training for integration of the iPad into their classroom instruction. Using a case study approach and the concerns-based adoption model as a framework, this study examined teachers' concerns about their training for using the iPads in the classroom. Participants were 7 teachers from a small, suburban, Catholic K-8 school who rated their lowest and highest concerns about using iPads in the classroom. Data sources included the Stages of Concern Questionnaire, Levels of Use observation rubric, and one-on-one interviews. Data analysis included open and axial coding for identification of themes and patterns. Results indicated teachers had little concern with gaining extra training on classroom time and organization and with conflicts between their interests and teaching responsibilities when integrating iPads. Results also indicated they had high levels of concern regarding developing working relationships with fellow faculty members to maximize the benefits of iPad training, as well as about receiving additional iPad training. Finally, results indicated teachers' concerns with acquiring more iPads for students, as well as acquiring greater network connectivity within the school. These results will aid administrators and designers with making positive changes to professional development that both improve and increase teachers' successful integration of mobile technology in their classrooms.

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30

Thankachan, Briju. "Concerns of Teachers: Information and Communication Technology (ICT)-Enabled Instruction in Kerala, India." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1385465581.

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31

Incerti, Federica. "Preservice Teachers’ Perceptions of Artificial Intelligence Tutors for Learning." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1585088861453228.

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32

"STDP Implementation Using CBRAM Devices in CMOS." Master's thesis, 2015. http://hdl.handle.net/2286/R.I.34779.

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abstract: Alternative computation based on neural systems on a nanoscale device are of increasing interest because of the massive parallelism and scalability they provide. Neural based computation systems also offer defect finding and self healing capabilities. Traditional Von Neumann based architectures (which separate the memory and computation units) inherently suffer from the Von Neumann bottleneck whereby the processor is limited by the number of instructions it fetches. The clock driven based Von Neumann computer survived because of technology scaling. However as transistor scaling is slowly coming to an end with channel lengths becoming a few nanometers in length, processor speeds are beginning to saturate. This lead to the development of multi-core systems which process data in parallel, with each core being based on the Von Neumann architecture. The human brain has always been a mystery to scientists. Modern day super computers are outperformed by the human brain in certain computations. The brain occupies far less space and consumes a fraction of the power a super computer does with certain processes such as pattern recognition. Neuromorphic computing aims to mimic biological neural systems on silicon to exploit the massive parallelism that neural systems offer. Neuromorphic systems are event driven systems rather than being clock driven. One of the issues faced by neuromorphic computing was the area occupied by these circuits. With recent developments in the field of nanotechnology, memristive devices on a nanoscale have been developed and show a promising solution. Memristor based synapses can be up to three times smaller than Complementary Metal Oxide Semiconductor (CMOS) based synapses. In this thesis, the Programmable Metallization Cell (a memristive device) is used to prove a learning algorithm known as Spike Time Dependant Plasticity (STDP). This learning algorithm is an extension to Hebb’s learning rule in which the synapses weight can be altered by the relative timing of spikes across it. The synaptic weight with the memristor will be its conductance, and CMOS oscillator based circuits will be used to produce spikes that can modulate the memristor conductance by firing with different phases differences.
Dissertation/Thesis
Masters Thesis Electrical Engineering 2015

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33

Chang, Hsiang-Yu, and 張翔喻. "Investigation on Resistive Switching Characteristics of CBRAM and T-RRAM Using High-k Materials." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/rs9mz6.

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34

"VerilogA Modelling of Programmable Metallization Cells." Master's thesis, 2014. http://hdl.handle.net/2286/R.I.25806.

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abstract: There is an ever growing need for larger memories which are reliable and fast. New technologies to implement non-volatile memories which are large, fast, compact and cost-efficient are being studied extensively. One of the most promising technologies being developed is the resistive RAM (ReRAM). In ReRAM the resistance of the device varies with the voltage applied across it. Programmable metallization cells (PMC) is one of the devices belonging to this category of non-volatile memories. In order to advance the development of these devices, there is a need to develop simulation models which replicate the behavior of these devices in circuits. In this thesis, a verilogA model for the PMC has been developed. The behavior of the model has been tested using DC and transient simulations. Experimental data obtained from testing PMC devices fabricated at Arizona State University have been compared to results obtained from simulation. A basic memory cell known as the 1T 1R cell built using the PMC has also been simulated and verified. These memory cells have the potential to be building blocks of large scale memories. I believe that the verilogA model developed in this thesis will prove to be a powerful tool for researchers and circuit developers looking to develop non-volatile memories using alternative technologies.
Dissertation/Thesis
Masters Thesis Electrical Engineering 2014

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35

"Kinetics of Programmable Metallization Cell Memory." Doctoral diss., 2011. http://hdl.handle.net/2286/R.I.8848.

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abstract: Programmable Metallization Cell (PMC) technology has been shown to possess the necessary qualities for it to be considered as a leading contender for the next generation memory. These qualities include high speed and endurance, extreme scalability, ease of fabrication, ultra low power operation, and perhaps most importantly ease of integration with the CMOS back end of line (BEOL) process flow. One area where detailed study is lacking is the reliability of PMC devices. In previous reliability work, the low and high resistance states were monitored for periods of hours to days without any applied voltage and the results were extrapolated to several years (>10) but little has been done to analyze the low resistance state under stress. With or without stress, the low resistance state appears to be highly stable but a gradual increase in resistance with time, less than one order of magnitude after ten years when extrapolated, has been observed. It is important to understand the physics behind this resistance rise mechanism to comprehend the reliability issues associated with the low resistance state. This is also related to the erase process in PMC cells where the transition from the ON to OFF state occurs under a negative voltage. Hence it is important to investigate this erase process in PMC cells under different conditions and to model it. Analyzing the programming and the erase operations separately is important for any memory technology but its ability to cycle efficiently (reliably) at low voltages and for more than 1E4 cycles (without affecting the cells performance) is more critical. Future memory technologies must operate with the low power supply voltages (<1V) required for small geometry nodes. Low voltage programming of PMC memory devices has previously been demonstrated using slow voltage sweeps and small numbers of fast pulses. In this work PMC memory cells were cycled at low voltages using symmetric pulses with different load resistances and the distribution of the ON and OFF resistances was analyzed. The effect of the program current used during the program-erase cycling on the resulting resistance distributions is also investigated. Finally the variation found in the behavior of similar resistance ON states in PMC cells was analyzed more in detail and measures to reduce this variation were looked into. It was found that slow low current programming helped reducing the variation in erase times of similar resistance ON states in PMC cells. This scheme was also used as a pre-conditioning technique and the improvements in subsequent cycling behavior were compared.
Dissertation/Thesis
Ph.D. Electrical Engineering 2011

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36

"Simulation Models for Programmable Metallization Cells." Master's thesis, 2013. http://hdl.handle.net/2286/R.I.20882.

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abstract: Advances in software and applications continue to demand advances in memory. The ideal memory would be non-volatile and have maximal capacity, speed, retention time, endurance, and radiation hardness while also having minimal physical size, energy usage, and cost. The programmable metallization cell (PMC) is an emerging memory technology that is likely to surpass flash memory in all the listed ideal memory characteristics. A comprehensive physics-based model is needed to fully understand PMC operation and aid in design optimization. With the intent of advancing the PMC modeling effort, this thesis presents two simulation models for the PMC. The first model is a finite element model based on Silvaco Atlas finite element analysis software. Limitations of the software are identified that make this model inconsistent with the operating mechanism of the PMC. The second model is a physics-based numerical model developed for the PMC. This model is successful in matching data measured from a chalcogenide glass PMC designed and manufactured at ASU. Matched operating characteristics observable in the current and resistance vs. voltage data include the OFF/ON resistances and write/erase and electrodeposition voltage thresholds. Multilevel programming is also explained and demonstrated with the numerical model. The numerical model has already proven useful by revealing some information presented about the operation and characteristics of the PMC.
Dissertation/Thesis
PMC numerical model written in M for Octave/MATLAB
M.S. Electrical Engineering 2013

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37

"Space Radiation Effects in Conductive Bridging Random Access Memory." Doctoral diss., 2018. http://hdl.handle.net/2286/R.I.51683.

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abstract: This work investigates the effects of ionizing radiation and displacement damage on the retention of state, DC programming, and neuromorphic pulsed programming of Ag-Ge30Se70 conductive bridging random access memory (CBRAM) devices. The results show that CBRAM devices are susceptible to both environments. An observable degradation in electrical response due to total ionizing dose (TID) is shown during neuromorphic pulsed programming at TID below 1 Mrad using Cobalt-60. DC cycling in a 14 MeV neutron environment showed a collapse of the high resistance state (HRS) and low resistance state (LRS) programming window after a fluence of 4.9x10^{12} n/cm^2, demonstrating the CBRAM can fail in a displacement damage environment. Heavy ion exposure during retention testing and DC cycling, showed that failures to programming occurred at approximately the same threshold, indicating that the failure mechanism for the two types of tests may be the same. The dose received due to ionizing electronic interactions and non-ionizing kinetic interactions, was calculated for each ion species at the fluence of failure. TID values appear to be the most correlated, indicating that TID effects may be the dominate failure mechanism in a combined environment, though it is currently unclear as to how the displacement damage also contributes to the response. An analysis of material effects due to TID has indicated that radiation damage can limit the migration of Ag+ ions. The reduction in ion current density can explain several of the effects observed in CBRAM while in the LRS.
Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2018

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38

"Cu-Silica Based Programmable Metallization Cell: Fabrication, Characterization and Applications." Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.44992.

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abstract: The Programmable Metallization Cell (PMC) is a novel solid-state resistive switching technology. It has a simple metal-insulator-metal “MIM” structure with one metal being electrochemically active (Cu) and the other one being inert (Pt or W), an insulating film (silica) acts as solid electrolyte for ion transport is sandwiched between these two electrodes. PMC’s resistance can be altered by an external electrical stimulus. The change of resistance is attributed to the formation or dissolution of Cu metal filament(s) within the silica layer which is associated with electrochemical redox reactions and ion transportation. In this dissertation, a comprehensive study of microfabrication method and its impacts on performance of PMC device is demonstrated, gamma-ray total ionizing dose (TID) impacts on device reliability is investigated, and the materials properties of doped/undoped silica switching layers are illuminated by impedance spectroscopy (IS). Due to the inherent CMOS compatibility, Cu-silica PMCs have great potential to be adopted in many emerging technologies, such as non-volatile storage cells and selector cells in ultra-dense 3D crosspoint memories, as well as electronic synapses in brain-inspired neuromorphic computing. Cu-silica PMC device performance for these applications is also assessed in this dissertation.
Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2017

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39

"Resistance Switching in Chalcogenide based Programmable Metallization Cells (PMC) and Sensors under Gamma-Rays." Doctoral diss., 2013. http://hdl.handle.net/2286/R.I.20918.

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abstract: Chalcogenide glass (ChG) materials have gained wide attention because of their applications in conductive bridge random access memory (CBRAM), phase change memories (PC-RAM), optical rewritable disks (CD-RW and DVD-RW), microelectromechanical systems (MEMS), microfluidics, and optical communications. One of the significant properties of ChG materials is the change in the resistivity of the material when a metal such as Ag or Cu is added to it by diffusion. This study demonstrates the potential radiation-sensing capabilities of two metal/chalcogenide glass device configurations. Lateral and vertical device configurations sense the radiation-induced migration of Ag+ ions in germanium selenide glasses via changes in electrical resistance between electrodes on the ChG. Before irradiation, these devices exhibit a high-resistance `OFF-state' (in the order of 10E12) but following irradiation, with either 60-Co gamma-rays or UV light, their resistance drops to a low-resistance `ON-state' (around 10E3). Lateral devices have exhibited cyclical recovery with room temperature annealing of the Ag doped ChG, which suggests potential uses in reusable radiation sensor applications. The feasibility of producing inexpensive flexible radiation sensors has been demonstrated by studying the effects of mechanical strain and temperature stress on sensors formed on flexible polymer substrate. The mechanisms of radiation-induced Ag/Ag+ transport and reactions in ChG have been modeled using a finite element device simulator, ATLAS. The essential reactions captured by the simulator are radiation-induced carrier generation, combined with reduction/oxidation for Ag species in the chalcogenide film. Metal-doped ChGs are solid electrolytes that have both ionic and electronic conductivity. The ChG based Programmable Metallization Cell (PMC) is a technology platform that offers electric field dependent resistance switching mechanisms by formation and dissolution of nano sized conductive filaments in a ChG solid electrolyte between oxidizable and inert electrodes. This study identifies silver anode agglomeration in PMC devices following large radiation dose exposure and considers device failure mechanisms via electrical and material characterization. The results demonstrate that by changing device structural parameters, silver agglomeration in PMC devices can be suppressed and reliable resistance switching may be maintained for extremely high doses ranging from 4 Mrad(GeSe) to more than 10 Mrad (ChG).
Dissertation/Thesis
Ph.D. Electrical Engineering 2013

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40

"Static Behavior of Chalcogenide Based Programmable Metallization Cells." Master's thesis, 2014. http://hdl.handle.net/2286/R.I.25917.

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abstract: Nonvolatile memory (NVM) technologies have been an integral part of electronic systems for the past 30 years. The ideal non-volatile memory have minimal physical size, energy usage, and cost while having maximal speed, capacity, retention time, and radiation hardness. A promising candidate for next-generation memory is ion-conducting bridging RAM which is referred to as programmable metallization cell (PMC), conductive bridge RAM (CBRAM), or electrochemical metallization memory (ECM), which is likely to surpass flash memory in all the ideal memory characteristics. A comprehensive physics-based model is needed to completely understand PMC operation and assist in design optimization. To advance the PMC modeling effort, this thesis presents a precise physical model parameterizing materials associated with both ion-rich and ion-poor layers of the PMC's solid electrolyte, so that captures the static electrical behavior of the PMC in both its low-resistance on-state (LRS) and high resistance off-state (HRS). The experimental data is measured from a chalcogenide glass PMC designed and manufactured at ASU. The static on- and off-state resistance of a PMC device composed of a layered (Ag-rich/Ag-poor) Ge30Se70 ChG film is characterized and modeled using three dimensional simulation code written in Silvaco Atlas finite element analysis software. Calibrating the model to experimental data enables the extraction of device parameters such as material bandgaps, workfunctions, density of states, carrier mobilities, dielectric constants, and affinities. The sensitivity of our modeled PMC to the variation of its prominent achieved material parameters is examined on the HRS and LRS impedance behavior. The obtained accurate set of material parameters for both Ag-rich and Ag-poor ChG systems and process variation verification on electrical characteristics enables greater fidelity in PMC device simulation, which significantly enhances our ability to understand the underlying physics of ChG-based resistive switching memory.
Dissertation/Thesis
Masters Thesis Electrical Engineering 2014

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41

"Programmable Metallization Cell Devices for Flexible Electronics." Doctoral diss., 2011. http://hdl.handle.net/2286/R.I.9513.

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abstract: Programmable metallization cell (PMC) technology is based on an electrochemical phenomenon in which a metallic electrodeposit can be grown or dissolved between two electrodes depending on the voltage applied between them. Devices based on this phenomenon exhibit a unique, self-healing property, as a broken metallic structure can be healed by applying an appropriate voltage between the two broken ends. This work explores methods of fabricating interconnects and switches based on PMC technology on flexible substrates. The objective was the evaluation of the feasibility of using this technology in flexible electronics applications in which reliability is a primary concern. The re-healable property of the interconnect is characterized for the silver doped germanium selenide (Ag-Ge-Se) solid electrolyte system. This property was evaluated by measuring the resistances of the healed interconnect structures and comparing these to the resistances of the unbroken structures. The reliability of the interconnects in both unbroken and healed states is studied by investigating the resistances of the structures to DC voltages, AC voltages and different temperatures as a function of time. This work also explores replacing silver with copper for these interconnects to enhance their reliability. A model for PMC-based switches on flexible substrates is proposed and compared to the observed device behavior with the objective of developing a formal design methodology for these devices. The switches were subjected to voltage sweeps and their resistance was investigated as a function of sweep voltage. The resistance of the switches as a function of voltage pulse magnitude when placed in series with a resistance was also investigated. A model was then developed to explain the behavior of these devices. All observations were based on statistical measurements to account for random errors. The results of this work demonstrate that solid electrolyte based interconnects display self-healing capability, which depends on the applied healing voltage and the current limit. However, they fail at lower current densities than metal interconnects due to an ion-drift induced failure mechanism. The results on the PMC based switches demonstrate that a model comprising a Schottky diode in parallel with a variable resistor predicts the behavior of the device.
Dissertation/Thesis
Ph.D. Electrical Engineering 2011

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42

"Multilevel Resistance Programming in Conductive Bridge Resistive Memory." Doctoral diss., 2015. http://hdl.handle.net/2286/R.I.36417.

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abstract: This work focuses on the existence of multiple resistance states in a type of emerging non-volatile resistive memory device known commonly as Programmable Metallization Cell (PMC) or Conductive Bridge Random Access Memory (CBRAM), which can be important for applications such as multi-bit memory as well as non-volatile logic and neuromorphic computing. First, experimental data from small signal, quasi-static and pulsed mode electrical characterization of such devices are presented which clearly demonstrate the inherent multi-level resistance programmability property in CBRAM devices. A physics based analytical CBRAM compact model is then presented which simulates the ion-transport dynamics and filamentary growth mechanism that causes resistance change in such devices. Simulation results from the model are fitted to experimental dynamic resistance switching characteristics. The model designed using Verilog-a language is computation-efficient and can be integrated with industry standard circuit simulation tools for design and analysis of hybrid circuits involving both CMOS and CBRAM devices. Three main circuit applications for CBRAM devices are explored in this work. Firstly, the susceptibility of CBRAM memory arrays to single event induced upsets is analyzed via compact model simulation and experimental heavy ion testing data that show possibility of both high resistance to low resistance and low resistance to high resistance transitions due to ion strikes. Next, a non-volatile sense amplifier based flip-flop architecture is proposed which can help make leakage power consumption negligible by allowing complete shutdown of power supply while retaining its output data in CBRAM devices. Reliability and energy consumption of the flip-flop circuit for different CBRAM low resistance levels and supply voltage values are analyzed and compared to CMOS designs. Possible extension of this architecture for threshold logic function computation using the CBRAM devices as re-configurable resistive weights is also discussed. Lastly, Spike timing dependent plasticity (STDP) based gradual resistance change behavior in CBRAM device fabricated in back-end-of-line on a CMOS die containing integrate and fire CMOS neuron circuits is demonstrated for the first time which indicates the feasibility of using CBRAM devices as electronic synapses in spiking neural network hardware implementations for non-Boolean neuromorphic computing.
Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2015

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43

"Characterization of Copper-doped Silicon Dioxide Programmable Metallization Cells." Doctoral diss., 2011. http://hdl.handle.net/2286/R.I.8900.

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abstract: Programmable Metallization Cell (PMC) is a resistance-switching device based on migration of nanoscale quantities of cations in a solid electrolyte and formation of a conducting electrodeposit by the reductions of these cations. This dissertation presents electrical characterization results on Cu-SiO2 based PMC devices, which due to the na- ture of materials can be easily integrated into the current Complimentary metal oxide semiconductor (CMOS) process line. Device structures representing individual mem- ory cells based on W bottom electrode and n-type Si bottom electrode were fabricated for characterization. For the W bottom electrode based devices, switching was ob- served for voltages in the range of 500mV and current value as low as 100 nA showing the electrochemical nature and low power potential. The ON state showed a direct de- pendence on the programming current, showing the possibility of multi-bit storage in a single cell. Room temperature retention was demonstrated in excess of 105 seconds and endurance to approximately 107 cycles. Switching was observed for microsecond duration 3 V amplitude pulses. Material characterization results from Raman, X-ray diffraction, Rutherford backscattering and Secondary-ion mass spectroscopy analysis shows the influence of processing conditions on the Cu concentration within the film and also the presence of Cu as free atoms. The results seemed to indicate stress-induced void formation in the SiO2 matrix as the driving mechanism for Cu diffusion into the SiO2 film. Cu/SiO2/nSi based PMC devices were characterized and were shown to have inherent isolation characteristics, proving the feasibility of such a structure for a passive array. The inherent isolation property simplifies fabrication by avoiding the need for a separate diode element in an array. The isolation characteristics were studied mainly in terms of the leakage current. The nature of the diode interface was further studied by extracting a barrier potential which shows it can be approximated to a Cu-nSi metal semiconductor Schottky diode.
Dissertation/Thesis
Ph.D. Electrical Engineering 2011

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Lee, Hung-Shan, and 李弘善. "Using Concerns-Based Adoption Model (CBAM) to Interpret How Teachers Implement Marine Education: A Case Study." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/s6f74c.

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博士
國立臺灣師範大學
科學教育研究所
106
In Taiwan, marine education has been a crucial agenda addressed in elementary and secondary school curricula. Yet, most teachers lack related content knowledge and are unfamiliar with the pedagogies. Consequently, there is an urgent need for the intervention of a knowledge broker who could bridge the gap between theory and practice. A professional development program was designed in this case study to meet this need. The program was designed under the framework of Concerns-Based Adoption Model (CBAM), which can be used to probe educational innovations. The knowledge broker replaces the facilitator in this framework. Data collected from the Stages of Concern (SoC) questionnaire, Levels of Use (LoU) interviews as well as Innovation Configurations Map (IC Map) of CBAM reveal the impact and the necessity of the knowledge broker. Two professional development workshops and on-line platforms were held to recruit long-term participants. Finally, a total of seventeen participants from a kindergarten, five primary schools, a junior high school and a vocational high school cooperated with the research team. Based on their initial SoC and LoU, appropriate assistances were provided. Presentations to participants’ students by the knowledge broker were asked by individual participant, and hands-on activities as well as equipment were designed or provided according to individual requirements. Thus, customized needs were satisfied through lengthy discussions between participants and the knowledge broker. The results show that for the behavioral aspects, all participants’ LoU advance to higher levels; their LoU reach to IVA and above, indicating all of them can carry out marine education routinely. For the perceptions about marine education, however, not all participants’ SoC reach to higher stages. Besides, IC indicates diversified modes of marine education observed from individual teachers. Based on these findings, the researcher concludes with practical implications for further implementations as well as research for marine education.

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Goulden, Wendy D. "Teacher Reactions to the Implementation of Full Day Kindergarten." Thesis, 2012. http://hdl.handle.net/1807/33651.

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Traditionally, kindergarten programs have been offered in various ways across the province of Ontario (e.g., half day every day; all day, alternate day). Starting in 2010, the Ontario Ministry of Education began implementing full day, every day kindergarten in all publically funded schools. This large-scale innovation has resulted in a number of important changes. The kindergarten teacher is experiencing a variety of these changes. This qualitative study focuses on reactions and concerns of kindergarten teachers as they begin to implement full day kindergarten. Semi-structured interviews and classroom observations with five kindergarten teachers provide information about these reactions and concerns. The Stages of Concern framework, one aspect of the Concerns-Based Adoption Model (CBAM), will be used to discuss these findings and how full day kindergarten has impacted the kindergarten teacher.

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Yeh, Hao-Po, and 葉晧博. "Action Research for efficacy of the inclusive process in elementary school based on Concern-Based Adoption Model(CBAM)." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/6sjew3.

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碩士
國立東華大學
特殊教育學系
100
This research, based on Concern-Based Adoption Model (CBAM), focused on the efficacy of inclusive education of regular classes in the elementary school, and the stages of concern and level of use with teachers in regular classes. This research designed by action research and taken in three stages. First, the researcher invited the evaluation team and probed in the first time in order to understand the style of the inclusive education, and compiling the main problem of implementing inclusive education. Second, the researcher explored and analyzed two study participants about the concerns and the level of use. According to the environmental resources and support system to develop the adaptation of the intervention. Finally, the evaluation team estimated the efficacy of inclusive education of regular classes in the elementary school again after the interventions improve the situation. The major findings were as follows, 1.The conforms to the degree of inclusion education were “half” and “most”. In which conforms to the degree by “Barrier Free Environment and the Assistive Technology” to be highest, others were “The school resources and the support system”, “The admission and the concern of school teachers and students” and “The adjustment of curriculum and teaching”. 2.Teacher’s concerns of inclusion include management concern, personal concern and informational concern. The level of use were mechanical use and routine. 3.CBAM may promote the efficacy of inclusive education of regular classes in the elementary school.

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Branco, Telmo Paiva. "Análise e mitigação do risco associado às infraestruturas de telecomunicações críticas de suporte à rede nacional de distribuição de eletricidade : uma visão baseada no redesenho da sua estratégia de manutenção : estágio na EDP distribuição." Master's thesis, 2015. http://hdl.handle.net/10400.26/16705.

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Este Relatório de Estágio apresenta uma análise e mitigação do risco envolvendo equipamentos de telecomunicações, considerados como críticos para a rede de distribuição elétrica portuguesa. Baseado numa avaliação da condição e do risco, foi criada uma estratégia de manutenção para reduzir o impacto e a probabilidade de falha dos equipamentos PDH, SDH, VHF, Microondas, Ethernet/IP e Fibra Ótica, que em conjunto representam a rede privativa de telecomunicações da EDP Distribuição (EDPD). A política Condition Based Risk Maintenance (CBRM) foi fundamental para atingir este objetivo e ofereceu as ferramentas necessárias para sustentar essa estratégia. Esta política, com base na condição e no risco, é normalmente associada a planos de manutenção de equipamentos na área da energia. No entanto, será demonstrado neste trabalho que pode ser aplicada com sucesso na área das telecomunicações, mais concretamente na manutenção de uma rede de telecomunicações industrial. O objetivo final foi apresentar uma estratégia de manutenção para a EDPD, para que a mesma seja usada na sua rede privativa de telecomunicações e dessa forma melhorar a gestão dos ativos da rede, reduzir os custos e manter a fiabilidade, observando e melhorando a matriz de risco da empresa. Para a elaboração da proposta de revisão da estratégia de manutenção foram recolhidos dados de várias bases de dados disponibilizadas pela empresa e toda a informação foi tratada com rigor e autocrítica. A análise dos registos de avarias permitiu criar gráficos detalhados da condição dos ativos por tipo de equipamento - este é o principal elemento do plano de manutenção que se pretende melhorar e que se baseia no tipo de equipamento e na sua condição ao longo to tempo. No entanto, a necessidade de uma maior disponibilidade dos equipamentos e a elevada criticidade dos elementos da rede, conduziu à necessidade de implementar uma filosofia baseada no risco, considerando a instalação no seu todo, levando à criação de diferentes perfis para os sites da rede. A Fibra Óptica (FO) teve uma análise independente das restantes tecnologias devido à sua importância extrema para a rede, encontrando-se a cargo do Departamento de Manutenção de Redes (MNRD), enquanto os restantes equipamentos são da responsabilidade do Departamento de Manutenção de Subestações (MNSE). Tendo por base o mesmo tipo de manutenção da condição ao longo do tempo, a manutenção associada à FO mereceu também melhorias, que se basearam na análise dos diferentes tipos de FO utilizados, onde cada um deles tem uma importância diferente para a rede. Foram recolhidos dados sobre a condição, o que permitiu elaborar uma ferramenta para o cálculo do Índice de Saúde, onde a avaliação do risco fica dependente das duas ou mais instalações envolvidas na Ligação FO. A proposta de manutenção para os equipamentos de telecomunicações elaborada foi entregue para avaliação na EDPD e está prevista a sua implementada no terreno a partir de janeiro de 2016. No que respeita à FO, foi disponibilizado e entregue para análise um modelo para a monitorização da sua condição e para a análise do seu índice de saúde, assim como uma nova proposta de manutenção para as ligações. Assim, pretendeu-se oferecer várias ferramentas para melhorar continuamente a rede privativa da EDPD, sem comprometer a fiabilidade e tentando reduzir ao máximo o tempo de indisponibilidade.

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"The Effect of Change Facilitation Coaching Using the Concerns-Based Adoption Model With an Urban Elementary School Teacher-leadership Team." Doctoral diss., 2014. http://hdl.handle.net/2286/R.I.24935.

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abstract: Public demands for accountability and educational change are at an all-time high. No Child Left Behind set the stage for public accountability of educators and the recently created Race to the Top grant raised the stakes of public school accountability even more with the creation of national standards and assessments as well as public accountability of individual teacher performance based on student test scores. This high-stakes context has placed pressure on local schools to change their instructional practices rapidly to ensure students are learning what they need to in order to perform well on looming Partnership for Assessment of Readiness for College and Careers (PARCC) exams. The purpose of this mixed methods action research study was to explore a shared leadership model and discover the impact of a change facilitation team using the Concerns Based Adoption Model tools on the speed and quality of innovation diffusion at a Title One elementary school. The nine-member change facilitation team received support for 20 weeks in the form of professional development and ongoing team coaching as a means to empower teacher-leaders to more effectively take on the challenges of change. Eight of those members participated in this research. This approach draws on the research on change, learning organizations, and coaching. Quantitative results from the Change Facilitator Stages of Concern Questionnaire were triangulated with qualitative data from interviews, field notes, and Innovation Configuration Maps. Results show the impact on instructional innovation when teacher-leadership is leveraged to support change. Further, there is an important role for change coaches when leading change initiatives. Implications from this study can be used to support other site leaders grappling with instructional innovation and calls for additional research.
Dissertation/Thesis
Ed.D. Educational Leadership and Policy Studies 2014

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49

Ferland, Annie. "Le téléenseignement avec la vidéoconférence et le développement professionnel d’enseignants du collégial." Thèse, 2013. http://hdl.handle.net/1866/10986.

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Beaucoup de cégeps voient leurs programmes techniques menacés à cause de la baisse démographique et de l’exode des jeunes. Cette situation est directement reliée à l’offre de formation : 46,1 % ont dû quitter leur région, car le programme d’études choisi n’y était pas offert. C’est en Gaspésie-Îles-de-la-Madeleine que pourrait s’effectuer la plus importante chute de clientèle, soit une baisse de plus de 40 % par rapport à l’effectif observé à l’automne 2008 (Bezy, 2011). Ce constat amène aussi son lot de questions quant au développement professionnel des enseignants. Un projet novateur se réalise dans cette région et pourrait aider à changer la situation. En effet, le cégep de la Gaspésie et des Iles a instauré une initiative de téléenseignement dans deux programmes (techniques de comptabilité et de gestion, soins infirmiers). Cette recherche vise à décrire les défis et obstacles auxquels sont confrontés les enseignants en processus de changement, ainsi que les avantages et bénéfices perçus de la pratique du téléenseignement, les changements de pratiques pédagogiques particuliers à la vidéoconférence, selon les différents niveaux d’adoption de la technologie. Pour mesurer ces différents aspects de leur pratique, le modèle CBAM (Hall & Hord, 2006) a été utilisé ainsi que le modèle de développement professionnel de (Clarke & Hollingsworth, 2002). Les résultats ont été obtenus par questionnaires (SoC et TAM) et entrevues (LoU et autres questions sur les principaux thèmes de cette recherche), ils permettent de dresser un portrait détaillé du rôle de ces enseignants tout en répondant aux objectifs de recherche. Des profils individuels et de groupes sont présentés pour cerner les caractéristiques de leur développement professionnel dans le cadre de cette innovation. Les résultats montrent de grandes similitudes entre les cas de l’échantillon (6 enseignants) et il ressort que les thèmes les plus préoccupants pour ces enseignants sont la gestion de classe et les défis techniques et pédagogiques que le téléenseignement implique.
Many colleges have their technical programs at risk due to demographic decline and the exodus of young people. This situation is directly related to the offer of formation: 46.1% had to leave their area because the chosen curriculum was not available. It is in Gaspésie-Îles-de-la-Madeleine that the biggest drop customers could happen, a decrease of over 40 % compared to the observions at fall 2008 (Bezy, 2011). This finding also raises a lot of questions about the professional development of teachers. An innovative project is carried out in this region and could help change the situation. Indeed, the Cégep de la Gaspésie et des Iles has established a distance learning initiative in two programs (accounting techniques and management, nursing care). This research is based on a sample of 6 teachers and aims to describe the challenges and obstacles faced by those, in the change process, and the benefits and perceived benefits of the practice of distance education. Also, the changes in individuals videoconferencing teaching practices according to different levels of adoption of technology. To measure these different aspects of their practice, the CBAM model (Hall & Hord, 2006) was used and the interconnected model of professional development (Clarke,2002). The results were obtained by questionnaires (SoC and TAM) and interviews (LoU and detailled interview on major topics of the study), they can provide a detailed overview of the role of these teachers while meeting the research objectives individual and group profiles portrait presented to identify characteristics of professional development in the context of this innovation. The results show great similarities between the cases in the sample (6 teachers) and it also show’s taht the most importants issues for these teachers are classroom management and technical and pedagogical challenges that distance learning requires.

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"Implementing a Standards-Based Teacher Evaluation System: Learning Experiences for Administrators in an Urban School District." Doctoral diss., 2012. http://hdl.handle.net/2286/R.I.14542.

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abstract: Policymakers at the national level have recently initiated K-12 education reforms focused on teacher quality and teacher evaluation. Far-reaching legislation was subsequently enacted in the state of Arizona requiring schools to adopt standards-based teacher evaluation systems and link them to student outcomes. The end product is to result in annual summative measures of teacher effectiveness. Because of this, Arizona school administrators have become concerned about rapidly becoming experts in high-stakes teacher evaluation. Principals rarely have time to come together to talk about teacher evaluation, and consider the reliability of their evaluations and how to use teacher evaluation to help teachers improve their practice. This action research study focused on a group of nine administrators in a small urban district grappling with a more complex and high-stakes teacher evaluation system. An existing community of practice was engaged to help administrators become more effective, fair, and consistent evaluators. Activities were designed to engage the group in dynamic, contextualized learning. Participants interacted in small groups to interpret the meaning of newly adopted evaluation instruments and professional teaching standards, share practical knowledge, and compare teacher evaluation experiences in classrooms. Data were gathered with mixed methods. Prior to, and immediately after engaging in this 20-week innovation, principals and district administrators were given two surveys and interviewed about teacher evaluation. Additionally, a detailed record of this project was kept in the form of meeting records and a research journal. Quantitative and qualitative data were triangulated to validate findings. Results identified concerns and understandings of administrators as they attempted to come to a shared consensus regarding teacher evaluation, increase inter-rater reliability, and use teacher evaluation to improve professional practice. As a result of working and learning together administrators lowered their concerns about inter-rater reliability. Other concerns, however, remained and grew. Administrators found the process of gaining a common understanding of teacher evaluation to be complex and far more time-consuming than anticipated. Intense concerns about alignment of the evaluation system with other reforms led these administrators to consider modifications in their evaluation system. Implications from this study can be used to help other administrators grappling with common concerns.
Dissertation/Thesis
Ed.D. Educational Leadership and Policy Studies 2012

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Dissertations / Theses on the topic 'CBRAM'

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