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Dahlquist, Fanny. "Junction Barrier Schottky Rectifiers in Silicon Carbide." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3367.
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Naredla, Sai Bhargav. "Electrical Properties of Molybdenum Silicon Carbide Schottky Barrier Diodes." Youngstown State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ysu155901806279725.
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Kashefi-Naini, A. "A study of some transition metal-silicon Schottky barrier diodes." Thesis, University of Kent, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375200.
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Morrison, Dominique Johanne. "The fabrication and characterisation of 4H-SiC Schottky barrier diodes." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324784.
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Wong, Frankie. "Mullite-mullite environmental barrier coatings on silicon nitride by composite sol-gel." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/12612.
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Silicon nitride is susceptible to paralinear oxidation in applications exposed to combustion environments, such as glow plugs in direct injection natural gas engines. The oxide layer may become volatile in moist high-temperature environments. To protect Si₃N₄, environmental barrier coatings (EBC) maybe used. Mullite has high corrosion resistance, high temperature strength, and its thermal expansion (CTE=4.5-6 x 10⁻⁶ /°C), is relatively close to that of Si₃N₄ (CTE=3.3 x 10⁻⁶ /°C). However, the CTEs still differ by a factor of 1.4-2, thus it is difficult to produce crack free EBCs >1 µm thick. To address this, it is proposed that a mullite-mullite EBC be applied by composite sol gel. The addition of calcined powder should reduce the overall shrinkage of the sol, making deposition of thicker (1-5µm) coatings possible. Processing methods to produce mullite-mullite EBC by composite sol gel were studied. Sol gel (SG) mullite precursors were prepared by combining silica-precursor sol with AlOOH sol. Commercially available calcined mullite (CM) was dispersed in the sol, with a solid loading of 36%. Gelation of these sols was studied and it was found that using AlOOH sols at a pH of 2.5 gave the best balance of gelation rate and CM sedimentation rate. Mullite sols were prepared and fired at different temperatures and times. It was determined that mullitizatoin of SG samples required 20min at 1300°C, however, CM addition allowed a similar extent of mullitization at 1250°C. It is hypothesized that the CM acted as seeds, shortening the nucleation step during mullite formation. Calcined samples had a density of 3.01g/cm³, with a total porosity of 9.4%. Glow plugs were dip coated. Final dipping parameters were sol viscosity of 40cps and withdrawal speed of 0.1mm/s. Calcined coatings with CM were relatively crack free with thicknesses of ~3μm. A coated glow plug was tested on an electric rig for effectiveness against oxidation. After 100hrs at 1300°C, the corrosion products layer on the coated glow plug was about one fourth as compared to the as received glow plugs. In conclusion, the composite sol-gel mullite EBC appears to provide significant oxidation protection to the silicon nitride glow plugs.
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Lin, Xin. "Yttrium disilicate as environmental barrier coating for silicon nitride-based glow plug." University of British Columbia, 2017. http://hdl.handle.net/2429/64165.
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Silicon-based ceramics undergo severe degradation at temperatures above ~1000 ℃ in the presence of water vapor, which is inevitable in combustion environments. Therefore, Environmental Barrier Coatings (EBCs) are necessary for the protection of Si₃N₄-based ceramic components in the harsh combustion environments. Rare earth silicates, which have relatively low thermal expansion coefficients, good chemical stability at high temperatures and low recession rates in the presence of water vapor, are promising candidate materials for such EBC application. This study was related to the application of Si₃N₄ as part of Hot Surface Ignition Systems (“Glow-Plugs”, GP) in High-Pressure Natural Gas Direct Injection engines, currently under development by Vancouver company Westport Fuel Systems Inc. For certain kinds of commercially available Si₃N₄-based GPs, the use of Y₂O₃ as sintering additive results in the in-service formation of yttrium silicates on their ceramic pins. Therefore, taking the chemical compatibility into consideration, yttrium disilicate coating was chosen to provide corrosion protection for such GPs. A sol-gel dip-coating route, which is simple, cost effective and industrially applicable, has been developed to apply multi-layer Y₂Si₂O₇ EBCs on the GPs. Selective processing parameters, including the sol aging conditions and the withdrawal speed of the GP substrate during dip coating procedure, were investigated in detail. The thickness and microstructures of the coatings were controlled through the adjustment of these parameters during sol preparation and dip coating processes. To simultaneously achieve sufficient thickness and avoid the formation of cracks, thin layers of Y₂Si₂O₇ coating, each with the thickness of ~1 µm, were successively applied and processed. The 6-layer crack-free coating was able to achieve an average thickness of ~5.5 µm. The microstructures of the coatings were evaluated and their performance was tested at ~1200 ℃ in high concentration water vapor atmosphere and on a natural gas burner rig. Improved corrosion resistance of such EBC-protected glow plugs was observed in these tests.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Fanaei, Sheikholeslami Tahereh. "Characterization of amorphous silicon carbide and its application to contact barrier diode." Thèse, Université de Sherbrooke, 2008. http://savoirs.usherbrooke.ca/handle/11143/1838.
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Résumé : Des couches minces du carbure silicium amorphe ont été préparées en utilisant un procédé de déposition en phase vapeur ayant comme source des polymères (PS-CVD). Les couches ont été déposées à des températures qui varient entre 750 et 1000°C. Les substrats utilisés pour dépôts sont en silicium cristallin du type p et n, et en dioxyde de silicium (SiO[indice inférieur 2]) obtenu par croissance thermique. Les propriétés chimiques et électriques des couches ont été étudiées par diverses techniques, y compris la spectroscopie infrarouge par transformé de Fourier, détection de recul élastique (ERD), et la mesure de capacité-tension. Nous avons observé une corrélation entre la concentration moyenne de l'oxygène dans les films et la température de déposition, liant une faible concentration en oxygène dans le film à une température élevée de déposition. Cependant, la concentration de l'oxygène dans les films déposés à la même température était indépendante du substrat. Les couches minces déposées à basse température ont démontré un comportement isolant, alors qu'un comportement semiconducteurest obtenu à température élevée. Des contacts ohmiques ont été obtenus sur la couche mince de carbure de silicium amorphe (a-SiC) en évaporant des contacts de nickel, suivis d'un recuit à 800 °C pendant 2 minutes. La mobilité de Hall moyenne obtenue est d'environ 34 cm[indice supérieur 2]/V.s pour les échantillons déposés sur (SiO[indice inférieur 2]) a 1000 °C. Les caractéristiques générales du a-SiC déposé à 750 °C, ont été étudiées se servant des hétérostructures de SiC/c-Si utilisés comme des diodes à barrière de contact. Les proprietés de transport du courant dans la couche mince de a-SiC déposée sur un substrat de c-Si detype-p ont été étudiés en utilisant des mesures courant-tension (IV) et capacité-tension (CV). Les caractéristiques IV ont montré qu'une dépendance exponentielle du courant aux tensions est applicable pour les basses tensions tandis que la caractéristique de courant limite par les charges de l'espace est dominante pour les hautes tensions. Les caractéristiques de CV ont indiqué un comportement de type-p pour a-SiC résultant de la charge positive injectée par le substrat de silicium. La mobilité des trous et la durée de vie des porteurs injectés dans la couche mince de a-SiC ont été calculées en utilisant un modèle du courant limite par les charges d'espace. La variation de la mobilité effective des trous de a-SiC varie entre 10[indice supérieur -4] et 10[indice supérieur -7] et attribué aux diverses valeurs de la densité des défauts dans les couches minces de a-SiC. // Abstract : Thin films of amorphous silicon carbide were prepared using Polymer-Source ChemicalVapor Deposition (PS-CVD) at températures between 750 and 1000 °C. The substrates weresilicon single crystal wafers of p-type and n-type, and thermally-grown silicon dioxidesubstrates. The chemical and electrical properties of the films were studied by varioustechniques, including Fourier-transform infrared spectroscopy, Elastic Recoil Detection(ERD), and capacitance-voltage technique. A correlation was observed between the averageconcentration of oxygen in the films and the deposition temperature, linking a low oxygenconcentration in the film to a high deposition temperature. However, the concentration ofoxygen in the films deposited at the same temperature was independent of the substrate. Thethin films deposited at low temperature showed insulating behaviour, while thesemiconducting behaviour was obtained at high deposition temperatures. Ohmic contactswere obtained on the deposited a-SiC thin film by evaporating nickel contacts, followed byannealing of the sample at 800 °C for 2 minutes. The average Hall mobility was found about µ[subscript H] = 34 cm[superscript 2]/V.s for the samples deposited on SiO[subscript 2] substrate at 1000 °C.The general characteristics of wide band gap a-SiC deposited at 750 °C, was studied using a-SiC/c-Si heterostructures applied as the contact barrier diodes. The current transportproperties of a-SiC thin film deposited on a p-type silicon c-Si substrate were investigatedusing current-voltage (IV) and capacitance-voltage (CV) measurements. IV characteristicsshowed an exponential dependence of current to the applied voltages for low forward biaswhile the space charge limited current characteristics dominated for higher forward bias. CVcharacteristics indicated a p-type property for a-SiC which is resulted by the injected positivecharge from p-type silicon substrate. The hole mobility and injected carrier lifetime in a-SiCthin film was calculated using a model of space-charge limited current. The variation ineffective hole mobility of a-SiC, which was ranged between
10[superscript -4] and 10[superscript -7], was attributed tothe various values of defect density of the a-SiC thin films.
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BREED, ANIKET AJITKUMAR. "SIMULATION STUDY OF PARASITIC BARRIER FORMATION IN Si/SiGe HETEROSTRUCTURES." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1029256143.
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Jarrell, Joshua Taylor. "High Temperature Characterization and Endurance Testing of Silicon Carbide Schottky Barrier Alpha Detectors." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1420467919.
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Chen, Li. "Adhesion/Diffusion Barrier Layers for Copper Integration: Carbon-Silicon Polymer Films and Tantalum Substrates." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc2255/.
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The Semiconductor Industry Association (SIA) has identified the integration of copper (Cu) with low-dielectric-constant (low-k) materials as a critical goal for future interconnect architectures. A fundamental understanding of the chemical interaction of Cu with various substrates, including diffusion barriers and adhesion promoters, is essential to achieve this goal. The objective of this research is to develop novel organic polymers as Cu/low-k interfacial layers and to investigate popular barrier candidates, such as clean and modified tantalum (Ta) substrates. Carbon-silicon (C-Si) polymeric films have been formed by electron beam bombardment or ultraviolet (UV) radiation of molecularly adsorbed vinyl silane precursors on metal substrates under ultra-high vacuum (UHV) conditions. Temperature programmed desorption (TPD) studies show that polymerization is via the vinyl groups, while Auger electron spectroscopy (AES) results show that the polymerized films have compositions similar to the precursors. Films derived from vinyltrimethyl silane (VTMS) are adherent and stable on Ta substrates until 1100 K. Diffusion of deposited Cu overlayers is not observed below 800 K, with dewetting occurred only above 400 K. Hexafluorobenzene moieties can also be incorporated into the growing film with good thermal stability. Studies on the Ta substrates demonstrate that even sub-monolayer coverages of oxygen or carbide on polycrystalline Ta significantly degrade the strength of Cu/Ta chemical interactions, and affect the kinetics of Cu diffusion into bulk Ta. On clean Ta, monolayer coverages of Cu will de-wet only above 600 K. A partial monolayer of adsorbed oxygen (3L O2 at 300 K) results in a lowering of the de-wetting temperature to 500 K, while saturation oxygen coverage (10 L O2, 300 K) results in de-wetting at 300 K. Carbide formation also lowers the de-wetting temperature to 300 K. Diffusion of Cu into the Ta substrate at 1100 K occurs only after a 5-minute induction period. This induction period increases to 10 min for partially oxidized Ta, 15 min for carbidic Ta and 20 min for fully oxidized Ta.
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Kummari, Rani S. "Improved SiC Schottky Barrier Diodes Using Refractory Metal Borides." Connect to resource online, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1266422079.
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Duran, Joshua. "Silicon-Based Infrared Photodetectors for Low-Cost Imaging Applications." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton155653478017603.
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Khan, Zuhair Subhani. "Development of environmental barrier coatings (EBC) on silicon carbide and SiC composites for advanced energy generation systems." Kyoto University, 2006. http://hdl.handle.net/2433/135552.
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Kyoto University (京都大学)0048
新制・課程博士
博士(エネルギー科学)
甲第12564号
エネ博第135号
新制||エネ||33(附属図書館)
UT51-2006-P24
京都大学大学院エネルギー科学研究科エネルギー応用科学専攻
(主査)教授 香山 晃, 教授 小西 哲之, 助教授 檜木 達也
学位規則第4条第1項該当
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Francheteau, Anaïs. "Superconducting silicon on insulator and silicide-based superconducting MOSFET for quantum technologies." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAY092/document.
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L'introduction de la supraconductivité dans des structures de type MOSFET en silicium ouvre de nouvelles perspectives dans la recherche en physique. Dans cette thèse, on s'intéresse aux propriétés de transport électronique au sein d'un MOSFET fabriqué avec des sources et drains supraconducteurs. Afin de garantir la reproductibilité de ces dispositifs, il est important d'intégrer des matériaux supraconducteurs compatibles avec la technologie CMOS exploitant la technologie silicium qui a pour énorme avantage d'être véritablement fiable et mature. L'idée fondamentale est de réaliser un nouveau type de circuit supraconducteur avec une géométrie de type transistor dans lequel un supracourant non dissipatif circulant au sein du dispositif, de la source vers le drain, serait modulé par une tension de grille : un JOFET. Une perspective importante est la réalisation d'un qubit supraconducteur grâce à une technologie parfaitement reproductible et mature. Cependant, à très basse température et avec la diminution de la taille des dispositifs, deux phénomènes a priori antagonistes entrent en compétition, à savoir la supraconductivité qui implique un grand nombre d'électrons condensés dans le même état quantique macroscopique et l'interaction Coulombienne qui décrit des processus de transport à une particule. L'intérêt de l'étude est donc de réaliser de tels transistors afin de mieux comprendre comment ce genre de dispositif hybride peut s'adapter à des propriétés opposées. Dans cette thèse, j'ai étudié deux façons d'introduire la supraconductivité dans nos dispositifs. La première option est de réaliser des sources et drains en silicium rendus supraconducteurs par dopage en bore et recuit laser effectué grâce à des techniques de dopage hors-équilibre robustes et bien maîtrisées. Même si la supraconductivité du silicium très fortement dopé en bore est connue depuis 2006 et son état supraconducteur a été très bien caractérisé sur des couches bidimensionnelles, la supraconductivité du SOI, qui est le substrat initial à la base de certains transistors, n'a jamais encore été testée et étudiée. L'objectif est de pouvoir adapter ces techniques de dopage au SOI afin de le rendre supraconducteur et de pouvoir l'intégrer par la suite dans des dispositifs de type MOSFET. La seconde option considérée est la réalisation de source et drain à base de siliciures supraconducteurs tel que le PtSi. Ce siliciure est intéressant du point de vue de sa température critique relativement haute de 1K. D'un point de vue technologique, les MOSFETs à barrière Schottky présentant des contacts en PtSi supraconducteur ont été élaborés au CEA/LETI. Les mesures à très basse température au sein d'un cryostat à dilution ont mis en évidence cette compétition entre la supraconductivité et les effets d'interaction Coulombienne et ont également révélé la supraconductivité dans le MOSFET comportant des contacts en PtSi grâce notamment à l'observation du gap induit dans le dispositifSuperconducting transport through a silicon MOSFET can open up many new possibilities ranging from fundamental research to industrial applications. In this thesis, we investigate the electric transport properties of a MOSFET built with superconducting source and drain contacts. Due to their advantages in terms of scalability and reproducibility, we want to integrate superconducting materials compatible with CMOS technology, thus exploiting the reliable and mature silicon technology. The idea is to realize a new type of superconducting circuits in a transistor geometry in which a non-dissipative supercurrent flowing through the device from source to drain will be modulated by a gate: a JOFET. One important outcome is the realization of superconducting qubits in a perfectly reproducible and mature technology. However, at low temperature and with the reduction of the size of the devices, two antagonistic phenomena appear. The dissipation-free transport of Cooper pairs competes with lossy single-particle processes due to Coulomb interactions. The goal is to understand how these two conflicting properties manifest in such hybrid devices. In this thesis, I studied two different ways of introducing superconductivity in the devices. We deployed a high boron doping and a laser annealing provided by well-controlled out-of-equilibrium doping techniques to make the silicon superconducting. Although highly boron-doped silicon has been known to be superconducting since 2006, superconductivity of SOI, the basic brick of some transistors, was never tested before. We aim at adapting those doping techniques on SOI in order to make it superconducting and to integrate it in transistor-like devices. In a second project, we study source and drain contacts fabricated with superconducting silicides such as PtSi. Such Schottky barrier MOSFETs with superconducting PtSi contacts are elaborated at the CEA/LETI. Measurements at very low temperature revealed the competition between superconductivity and Coulomb interactions and moreover, have brought evidence of superconductivity in PtSi based silicon Schottky barrier MOSFET
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Hajsaid, Marwan. "Photoresponse study of platinum silicide Schottky-barrier diodes and electrical characterization of porous silicon with some device applications /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9717171.
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Pirolli, Laurent. "Chemical and physical understanding of diffusion barrier layers on semiconductors: (hfac)copper(VTMS) and its ligands on silicon(100)-2 x 1 and titanium carbon nitride-covered silicon." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 3.19 Mb., 254 p, 2006. http://proquest.umi.com/pqdlink?did=1179959861&Fmt=7&clientId=8331&RQT=309&VName=PQD.
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Thesis (Ph. D.)--University of Delaware, 2006.Principal faculty advisor: Andrew V. Teplyakov, Dept. of Chemistry & Biochemistry and Raul F. Lobo, Dept. of Chemical Engineering. Includes bibliographical references.
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Leu, Jihperng, H. E. Tu, W. Y. Chang, C. Y. Chang, Y. C. Chen, W. C. Chen, and H. Y. Zhou. "Low-k SiCxNy Etch-Stop/Diffusion Barrier Films for Back-End Interconnect Applications." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-207243.
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Lower k and low-leakage silicon carbonitride (SiCxNy ) films were fabricated using single precursor by using radio-frequency (RF) plasma-enhanced chemical vapor deposition (PECVD). We explored precursors with (1) cyclic-carbon-containing structures, (2) higher C/Si ratio, (3) multiple vinyl groups, as well as (4) the incorporation of porogen for developing low-k SiCxNy films as etch-stop/diffusion barrier (ES/DB) layer for copper interconnects in this study. SiCxNy films with k values between 3.0 and 3.5 were fabricated at T≦ 200 o C, and k~4.0-4.5 at 300-400 °C. Precursors with vinyl groups yielded SiCxNy films with low leakage, excellent optical transmittance and high mechanical strength due to the formation of cross-linked Si-(CH2)n-Si linkages.
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Hon, Kam Yan. "Surface plasmon resonance-assisted coupling to whispering-gallery modes in micropillar resonators and silicon microdisk-based depletion-type modulators using integrated schottky diodes /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?ECED%202007%20HON.
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Ding, Yi. "Quantum well state of cubic inclusions in hexagonal silicon carbide studied with ballistic electron emission microscopy." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1086207334.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xv, 150 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Jonathan P. Pelz, Dept. of Physics. Includes bibliographical references (p. 144-150).
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Pregl, Sebastian. "Fabrication and characterization of a silicon nanowire based Schottky-barrier field effect transistor platform for functional electronics and biosensor applications." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-171112.
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This work focuses on the evaluation of the feasibility to employ silicon (Si) nanowire based parallel arrays of Schottky-barrier field effect transistors (SB-FETs) as transducers for potentiometric biosensors and their overall performance as building blocks for novel functional electronics. Nanowire parallel arrays of SB-FETs were produced and electrically characterized during this work. Nominally undoped Si nanowires with mean diameter of 20nm were synthesized by chemical vapor deposition (CVD) driven bottom-up growth and subsequently transferred via a printing process to Si/SiO2 chip substrates. Thereby, dense parallel aligned nanowire arrays are created. After dry oxidation of the nanowires, standard photolithography and deposition methods are employed to contact several hundred nanowires with interdigitated Ni electrodes in parallel. A silicidation step is used to produce axially intruded Ni-silicide (metallic) phases with a very abrupt interface to the Si (semiconducting) segment. Acting as front gate dielectric, the chip surface is entirely covered by an Al2O3 layer. For sensor applications, this layer further serves as electrical isolation of the electrodes and protects them from corrosion in electrolytes. Fabricated devices are part of the SOI (Si on insulator) transistor family with top (front) and back gate and exhibit ambipolar rectifying behavior. The top gate exhibits omega geometry with a 20nm thin Al2O3 dielectric, the back gate planar geometry with a 400nm thick SiO2 dielectric. The influence of both gates on the charge transport is summarized in the statistical analysis of transfer and output characteristic for 7 different lengths (for each 20 devices) of the Si conduction channel. A nonlinear scaling of on-currents and transconductance with channel length is revealed. Off-currents are influenced from both p- and n-type conduction at the same time. Increasing lateral electric fields (LEF) lead to a decline of suppression capability of both p- and n-currents by a single gate. This is reflected in a deteriorated swing and higher off-current towards decreasing channel lengths (increasing LEF). However, by individual gating of Schottky junction and channel, p- and n-type currents can be controlled individually. Both charge carrier types, p and n, can be suppressed efficiently at the same time leading to low off-currents and high on/off current ratio for all investigated channel lengths. This is achieved by a combined top and back double gate architecture, for which the back gate controls the Schottky junction resistance. It is demonstrated that a fixed high Schottky junction serial resistance, severely impairs the transconductance. However, the transconductance can be significantly increased by lowering this resistance via the back gate, enhancing the transducer performance significantly. Al2O3 covered SB-FETs were employed as pH sensors to evaluate their performance and signal to noise ratio (SNR). Current modulation per pH was observed to be directly proportional to the transconductance. The transistor related signal to noise ratio (SNR) is thus proportional to the transconductance to current noise ratio. Device noise was characterized and found to limit the SNR already below the peak transconductance regime. Statistical analysis showed that the nanowire SB-FET transconductance and noise both scale proportional with the current. Therefore, the SNR was found to be independent on the nanowire channel lengths under investigation. The high process yield of nanowire SB-FET parallel array fabrication close to hundred percent enables this platform to be used for simple logic and biosensor elements. Because of the low fabrication temperatures needed, the foundation is laid to produce complementary logic with undoped Si on flexible substrates. For previously reported results, the presence of Schottky junctions severely impaired the transconductance, restricting the applicability of SB-FETs as transducers. This work shows, that an electric decoupling of the Schottky junction can reduce these restrictions, making SB-FETs feasible for sensor applicationsDiese Dissertation ist der Bewertung von Silizium (Si) Nanodraht basierten Parallelschaltungen von Schottky-Barrieren-Feld-Effekt-Transistoren (SB-FETs) als Wandler für potentiometrische Biosensoren und deren generelle Leistungsfähigkeit als Bauelement neuartiger funktioneller Elektronik gewidmet. In dieser Arbeit wurden Parallelschaltungen von Nanodraht SB-FETs hergestellt und elektrisch charakterisiert. Nominell undotierte Si Nanodrähte mit durchschnittlichem Durchmesser von 20nm wurden mittels chemischer Dampfphasenabscheidung (CVD) synthetisiert und anschließend durch einen Druckprozess auf ein Si/SiO2 Chip-Substrat transferiert. Damit wurden dicht gepackte, parallel ausgerichtete Nanodraht Schichten erzeugt. Nach Trockenoxidation der Nanodrähte wurden diese mit Standard Lithographie und Abscheidungsmethoden mit interdigitalen Nickel (Ni) Elektroden als Parallelschaltung kontaktiert. Durch einen Temperprozess bilden sich axial eindiffundierte metallische Ni-Silizid-Phasen, mit einer sehr abrupten Grenzfläche zum halbleitenden Si Segments des Nanodrahts. Die Chipoberfläche wird vollständig mit einer Al2O3-Schicht bedeckt, welche als Frontgate-Dielektrikum oder als elektrische Isolation und Korrosionsschutzschicht für Elektroden in Elektrolytlösungen im Falle der Sensoranwendungen dient. Die hier gezeigten Bauelemente sind Teil der SOI (Si on insulator) Transistoren-Familie mit Top- (Front) und Backgate und zeigen ein ambipolares Schaltverhalten. Die Topgates besitzen eine Omega-Geometrie mit 20nm dickem Al2O3 Dielektrikum, das Backgate eine planare Geometrie mit 400nm dickem SiO2 Dielektrikum. Der Einfluss beider Gates auf den Ladungstransport ist in einer statistischen Analyse der Transfer- und Output-Charaktersitiken für 7 unterschiedliche Si-Leitungskanallängen zusammengefasst. Eine nichtlineare Skalierung von Strom und Transkonduktanz mit Leitungskanallänge wurde aufgedeckt. Die Ströme im Aus-Zustand des Transistors sind durch das Vorhandensein gleichzeitiger p- als auch n-Typ Leitung bestimmt. Die Zunahme lateraler elektrischer Felder (LEF) führt zu einem Verlust des gleichzeitigen Ausschaltvermögens von p- und n-Strömen bei Ansteuerung mit einem einzelnen Gate. Dies äußert sich durch einen graduell verschlechterten Swing und höheren Strom im Aus-Zustand bei verringerter Leitungskanallänge (gleichbedeutend mit erhöhten LEF). Durch eine getrennte Ansteuerung von Schottky-Kontakt und Leitungskanal lassen sich p- and n-Leitung jedoch unabhängig voneinander kontrollieren. Beide Ladungsträgertypen können so simultan effizient unterdrückt werden, was zu einem geringen Strom im Aus-Zustand und einem hohen An/Aus- Stromverhältnis für alle untersuchten Kanallängen führt. Dies wird durch eine Gatearchitektur mit kombiniertem Top- und Backgate erreicht, bei der das Backgate den Ladungstransport durch den Schottky-Kontakt und dessen Serienwiderstand kontrolliert. Es wird gezeigt, dass ein konstant hoher Schottky-Kontakt bedingter Serienwiderstand die Transkonduktanz erheblich vermindert. Jedoch kann die Transkonduktanz im höchsten Maße durch eine Herabsetzung des Serienwiderstandes durch das Backgate gesteigert werden. Dies erhöht die Leistungsfähigkeit des SB-FET als Wandler deutlich. Al2O3 oberflächenbeschichtete SB-FETs wurden als pH-Sensoren erprobt, um deren Tauglichkeit und Signal-zu-Rausch-Verhältnis (SNR) zu evaluieren. Die Strommodulation pro pH-Wert konnte als direkt proportional zur Transkonduktanz bestätigt werden. Das Transistor bedingte SNR ist daher proportional zum Verhältnis von Transkonduktanz und Stromrauschen. Bei der Analyse des Transistorrauschens wurde festgestellt, dass dieses das SNR bereits bei einer niedrigeren Transkonduktanz als der maximal Möglichen limitiert. Eine statistische Auswertung zeigte, dass sowohl SB-FET Transkonduktanz als auch Stromrauschen proportional zu dem Transistorstrom skalieren. Somit ist deren Verhältnis unabhängig von der Nanodraht-Leitungskanallänge, im hier untersuchten Rahmen. Die geringe Ausschuss bei der Fabrikation der Nanodraht SB-FET-Parallelschaltungen ermöglicht eine Nutzung dieser Plattform für simple Logik und Biosensorelemente. Durch die geringen Prozesstemperaturen wurde die Grundlage geschaffen, komplementäre Logik mit undotiertem Si auf flexiblen Substraten zu fertigen. Vorangegangene Resultate zeigte eine verminderte Transkonduktanz durch die Präsenz von Schottky-Barrieren, was die Anwendbarkeit von SB-FETs als Wandler einschränkt. Diese Arbeit zeigt, dass eine elekrtische Entkopplung der Schottky-Kontakte zu einer Aufhebung dieser Beschränkung führen kann und somit den Einsatz von SB-FETs als praktikable Wandler für Sensoranwendungen zulässt
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Hu, Yike. "Production and properties of epitaxial graphene on the carbon terminated face of hexagonal silicon carbide." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/48705.
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Graphene is widely considered to be a promising candidate for a new generation of electronics, but there are many outstanding fundamental issues that need to be addressed before this promise can be realized. This thesis focuses on the production and properties of graphene grown epitaxially on the carbon terminated face (C-face) of hexagonal silicon carbide leading to the construction of a novel graphene transistor structure. C-face epitaxial graphene multilayers are unique due to their rotational stacking that causes the individual layers to be electronically decoupled from each other. Well-formed C-face epitaxial graphene single layers have exceptionally high mobilities (exceeding 10,000 cm ²/Vs), which are significantly greater than those of Si-face graphene monolayers. This thesis investigates the growth and properties of C-face single layer graphene. A field effect transistor based on single layer graphene was fabricated and characterized for the first time. Aluminum oxide or boron nitride was used for the gate dielectric. Additionally, an all graphene/SiC Schottky barrier transistor on the C-face of SiC composed of 2DEG in SiC/Si₂O ₃ interface and multilayer graphene contacts was demonstrated. A multiple growth scheme was adopted to achieve this unique structure.
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Berthou, Maxime. "Implementation of high voltage Silicon Carbide rectifiers and switches." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00770661.
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In this document, we present ou study about the conception and realization of VMOS and Schottky and JBS Diodes on Silicon Carbide. This work allowed us optimize and fabricate diodes using Tungsten as Schottky barrier on both Schottky and JBS diodes of different blocking capability between 1.2kV and 9kV. Moreover, our study of the VMOS, by considering the overall fabrication process, has permitted to identify the totality of the problems we are facing. Thusly we could ameliorate the devices and try new designs as the VIEMOS or the monolithic integration of temperature and current sensors.
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Ho, Kang Jin. "Studies on Amorphous Silicon Thin Films Doped with Aluminium." Thesis, Indian Institute of Science, 1995. http://hdl.handle.net/2005/157.
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Amorphous Silicon(a-Si) films have attracted the attention of several investigators as it is an economical material for devices. One of the problems that is addressed is the doping of these films after they are prepared.
In this thesis, we investigated the effects of doping amorphous Silicon films(prepared by r.f. sputtering) with Aluminium(Al) by thermal diffusion. Amorphous Silicon films have been prepared on glass substrates at optimal process parameters. Then, the a-Si films are coated with Al by vacuum evaporation and subjected to heating in N2 atmosphere in the temperature range 300°C to 600°C for different durations.
After etching Al layer, it has been found that some of the films which are heated around 550°C contain filament like polycrystalline regions surrounding islands of a-Si.
This structure has been confirmed through Scanning Electron Mi-croscope(SEM) photographs and electrical conductivity measurements. SEM photographs indicate that, bright regions of amorphous material are surrounded by dark regions of relatively higher conducting
boundaries.
The electrical conductivity study shows that there is sharp increase in conductivity of Al doped films, which is attributed to the conducting polycrystalUne filament.
A simple model has been proposed to explain the variation of conductivity of these transformed films, with process parameters and with temperature.
Schottky barrier diodes have been fabricated using these transformed materials and their characteristics explained.
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Hanif, Raza. "Microfabrication of Plasmonic Biosensors in CYTOP Integrating a Thin SiO2 Diffusion and Etch-barrier Layer." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19880.
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A novel process for the fabrication of Long Range Surface Plasmon Polariton (LRSPP) waveguide based biosensors is presented herein. The structure of the biosensor is comprised of Au stripe waveguide devices embedded in thick CYTOP claddings with a SiO2 solvent diffusion barrier and etch-stop layer. The SiO2 layer is introduced to improve the end quality of Au waveguide structures, which previously deformed during the deposit of the upper cladding process and to limit the over-etching of CYTOP to create micro-fluidic channels. The E-beam evaporation method is adapted to deposit a thin SiO2 on the bottom cladding of CYTOP. A new micro-fluidic design pattern is introduced. Micro-fluidic channels were created on selective Au waveguides through O2 plasma etching. The presented data and figures are refractive index measurements of different materials, thickness measurements, microscope images, and AFM images. Optical power cutback measurements were performed on fully CYTOP-cladded symmetric LRSPP waveguides. The end-fire coupling method was used to excite LRSPP modes with cleaved polarization maintaining (PM) fibre. The measured mode power attenuation (MPA) was 6.7 dB/mm after using index-matched liquid at input and output fibre-waveguide interfaces. The results were compared with the theoretical calculations and simulations. Poor coupling efficiency and scattering due to the SiO2 are suspected for off-target measurements.
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White, Brad D. "Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1141325302.
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White, Brad Derek. "Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1141325302.
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Belkouch, Said. "Etude électronique et physicochimique de la structure Pt/a-Si:H/c-Si(n)." Grenoble 1, 1989. http://www.theses.fr/1989GRE10086.
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On montre que la concentration des defauts profonds croit lorsque l'epaisseur d d'un silicium hydrogene si:h diminue. Les courbes (v,t) tension-temperature sont du type schottky avec des facteurs d''idealite qui augmentent quand t decroit. Des mesures c(v,), on en deduit la chute du potentiel electrostatique q#s dans le c-si pour chaque epaisseur d en fonction de la tension v appliquee. Les mesures photoelectriques sont effectuees afin de determiner et de caracteriser les defauts de la structure
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Lee, Sang Kwon. "Processing and characterization of silicon carbide (6H-SiC and 4H-SiC) contacts for high power and high temperature device applications." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3335.
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Silicon carbide is a promising wide bandgap semiconductormaterial for high-temperature, high-power, and high-frequencydevice applications. However, there are still a number offactors that are limiting the device performance. Among them,one of the most important and critical factors is the formationof low resistivity Ohmic contacts and high-temperature stableSchottky diodes on silicon carbide.
In this thesis, different metals (TiW, Ti, TiC, Al, and Ni)and different deposition techniques (sputtering andevaporation) were suggested and investigated for this purpose.Both electrical and material characterizations were performedusing various techniques, such as I-V, C-V, RBS, XRD, XPS,LEED, SEM, AFM, and SIMS.
For the Schottky contacts to n- and p-type 4H-SiC, sputteredTiW Schottky contacts had excellent rectifying behavior afterannealing at 500 ºC in vacuum with a thermally stableideality factor of 1.06 and 1.08 for n- and p-type,respectively. It was also observed that the SBH for p-type SiC(ΦBp) strongly depends on the choice the metal with alinear relationship ΦBp= 4.51 - 0.58Φm, indicating no strong Fermi-level pinning.Finally, the behavior of Schottky diodes was investigated byincorporation of size-selected Au nano-particles in Ti Schottkycontacts on silicon carbide. The reduction of the SBH isexplained by using a simple dipole layer approach, withenhanced electric field at the interface due to the small sizeof the circular patch (Au nano-particles) and large differenceof the barrier height between two metals (Ti and Au) on both n-and p-SiC.
For the Ohmic contacts, titanium carbide (TiC) was used ascontacts to both n- and p-type 4H-SiC epilayers as well as onAl implanted layers. The TiC contacts were epitaxiallydeposited using a co-evaporation method with an e-beam Tisource and a Knudsen cell for C60, in a UHV system at low substrate temperature(500 ºC). In addition, we extensively investigatedsputtered TiW (weight ratio 30:70) as well as evaporated NiOhmic contacts on both n- and p-type epilayers of SiC. The bestOhmic contacts to n-type SiC are annealed Ni (>950ºC)with the specific contact resistance of ≈ 8× 10-6Ω cm2with doping concentration of 1.1 × 10-19cm-3while annealed TiW and TiC contacts are thepreferred contacts to p-type SiC. From long-term reliabilitytests at high temperature (500 ºC or 600 ºC) invacuum and oxidizing (20% O2/N2) ambient, TiW contacts with a platinum cappinglayer (Pt/Ti/TiW) had stable specific contact resistances for>300 hours.
Keywords: silicon carbide, Ohmic and Schottky contacts,co-evaporation, current-voltage, capacitance-voltagemeasurement, power devices, nano-particles, Schottky barrierheight lowering, and TLM structures.
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Pregl, Sebastian Verfasser], Gianaurelio [Akademischer Betreuer] Cuniberti, and Paolo [Akademischer Betreuer] [Lugli. "Fabrication and characterization of a silicon nanowire based Schottky-barrier field effect transistor platform for functional electronics and biosensor applications / Sebastian Pregl. Gutachter: Gianaurelio Cuniberti ; Paolo Lugli. Betreuer: Gianaurelio Cuniberti." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/1073781143/34.
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Pregl, Sebastian [Verfasser], Gianaurelio Akademischer Betreuer] Cuniberti, and Paolo [Akademischer Betreuer] [Lugli. "Fabrication and characterization of a silicon nanowire based Schottky-barrier field effect transistor platform for functional electronics and biosensor applications / Sebastian Pregl. Gutachter: Gianaurelio Cuniberti ; Paolo Lugli. Betreuer: Gianaurelio Cuniberti." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/1073781143/34.
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Pilli, Aparna. "Atomic Layer Deposition of Boron Oxide and Boron Nitride for Ultrashallow Doping and Capping Applications." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1752373/.
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The deposition of boron oxide (B₂O₃) films on silicon substrates is of significant interest in microelectronics for ultrashallow doping applications. However, thickness control and conformality of such films has been an issue in high aspect ratio 3D structures which have long replaced traditional planar transistor architectures. B₂O₃ films are also unstable in atmosphere, requiring a suitable capping barrier for passivation. The growth of continuous, stoichiometric B₂O₃ and boron nitride (BN) films has been demonstrated in this dissertation using Atomic Layer Deposition (ALD) and enhanced ALD methods for doping and capping applications.
Low temperature ALD of B₂O₃ was achieved using BCl₃/H₂O precursors at 300 K. In situ x-ray photoelectron spectroscopy (XPS) was used to assess the purity and stoichiometry of deposited films with a high reported growth rate of ~2.5 Å/cycle. Free-radical assisted ALD of B₂O₃ was also demonstrated using non-corrosive trimethyl borate (TMB) precursor, in conjunction with mixed O₂/O-radical effluent, at 300 K. The influence of O₂/O flux on TMB-saturated Si surface was investigated using in situ XPS, residual gas analysis mass spectrometer (RGA-MS) and ab initio molecular dynamics simulations (AIMD). Both low and high flux regimes were studied in order to understand the trade-off between ligand removal and B₂O₃ growth rate. Optimization of precursor flux was discovered to be imperative in plasma and radical-assisted ALD processes.
BN was investigated as a novel capping barrier for B₂O₃ and B-Si-oxide films. A BN capping layer, deposited using BCl₃/NH₃ ALD at 600 K, demonstrated excellent stoichiometry and consistent growth rate (1.4 Å/cycle) on both films. Approximately 13 Å of BN was sufficient to protect ~13 Å of B₂O₃ and ~5 Å of B-Si-oxide from atmospheric moisture and prevent volatile boric acid formation. BN/B₂O₃/Si heterostructures are also stable at high temperatures (>1000 K) commonly used for dopant drive-in and activation. BN shows great promise in preventing upward boron diffusion which causes a loss in the dopant dose concentration in Si.
The capping effects of BN were extended to electrochemical battery applications. ALD of BN was achieved on solid Li-garnet electrolytes using halide-free tris(dimethylamino)borane precursor, in conjunction with NH₃ at 723 K. Approximately 3 nm of BN cap successfully inhibited Li₂CO₃ formation, which is detrimental to Li-based electrolytes. BN capped Li-garnets demonstrated ambient stability for at least 2 months of storage in air as determined by XPS. BN also played a crucial role in stabilizing Li anode/electrolyte interface, which drastically reduced interfacial resistance to 18 Ω.cm², improved critical current density and demonstrated excellent capacitance retention of 98% over 100 cycles. This work established that ALD is key to achieving conformal growth of BN as a requirement for Li dendrite suppression, which in turn influences battery life and performance.
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Martin, Christian Dominik. "Spatially resolved studies of the leakage current behavior of oxide thin-films." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16746.
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Im Laufe der Verkleinerungen integrierter Schaltungen ergab sich die Notwendigkeit der alternativen dielektrischen Materialen. Hohe Polarisierbarkeiten in diesen dielektrischen Dünnfilmen treten erst in hoch direktionalen kristallinen Phasen auf. Aufgrund der erschwerten Integrierbarkeit von epitaktischen, einkristallinen Oxidfilmen können nur poly-, beziehungsweise nanokristalle Filme eingesetzt werden. Diese sind jedoch mit hohen Leckströmen behaftet. Weil die Information in einer DRAM-Zelle als Ladung in einem Kondensator gespeichert wird ist der Verlust dieser Ladung durch Leckströme die Ursache für Informationsverluste. Die Frequenz der notwendigen Auffrischungszyklen einer DRAM-Zelle wird direkt durch die Leckströme bestimmt. Voraussetzungen für die Entwicklung neuer dielektrischer Materialien ist das Verständnis der zugrunde liegenden Ladungsträgertransportmechanismen und ein Verständnis der strukturellen Schichteigenschaften, welche zu diesen Leckströmen führen. Conductive atomic force Microscopy ist ein Rastersondenmethode mit der strukturelle Eigenschaften mit lokaler elektrischer Leitfähigkeit korreliert wird. Mit dieser Methode wurde in einer vergleichenden Studie die räumlichen Leckstromverteilungen untersucht. Und es wurde gezeigt, dass es genügt eine nicht geschlossene Zwischenschicht Aluminiumoxid in eine Zirkoniumdioxidschicht zu integrieren um die Leckströme signifikant zu reduzieren während eine ausreichend hohe Kapazität erhalten bleibt. Darüberhinaus wurde ein CAFM modifiziert und benutzt um das Schaltverhalten eines Siliziumnanodrahtschottkybarrierenfeleffektransistor in Abhängigkeit der Spitzenposition zu untersuchen. Es konnte experimentell bestätigt werden das die Schottkybarrieren den Ladungstransport in diesen Bauteilen kontrollieren. Darüber hinaus wurde ein proof-of-concept für eine umprogrammierbaren nichtflüchtigen Speicher, der auf Ladungsakkumulation und der resultierenden Bandverbiegung an den Schottkybarrieren basiert, gezeigt.In the course of the ongoing downscaling of integrated circuits the need for alternative dielectric materials has arisen. The polarizability of these dielectric thin-films is highest in highly directional crystalline phases. Since epitaxial single crystalline oxide films are very difficult to integrate into the complex DRAM fabrication process, poly- or nanocrystalline thin-films must be used. However these films are prone to very high leakage currents. Since the information is stored as charge on a capacitor in the DRAM cell, the loss of this charge through leakage currents is the origin of information loss. The rate of the necessary refresh cycles is directly determined by these leakage currents. A fundamental understanding of the underlying charge carrier transport mechanisms and an understanding of the structural film properties leading to such leakage currents are essential to the development of new, dielectric thin-film materials. Conductive Atomic Force Microscopy (CAFM) is a scanning probe based technique which correlates structural film properties with local electrical conductivity. This method was used to examine the spatial distribution of leakage currents in a comparative study. I was shown that it is sufficient to include an unclosed interlayer of Aluminium oxide into a Zirconium dioxide film to significantly reduce leakage currents while maintaining a sufficiently high capacitance. Moreover, a CAFM was modified and used to examine the switching behavior of a silicon nanowire Schottky barrier field effect transistors in dependence of the probe position. It was proven experimentally that Schottky barriers control the charge carrier transport in these devices. In addition, a proof of concept for a reprogrammable nonvolatile memory device based on charge accumulation and band bending at the Schottky barriers was shown.
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Pooley, David Martin. "Vertical silicon single-electron devices with silicon nitride tunnel barriers." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621302.
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Anderson, Tom Harper. "Optoelectronic simulation of nonhomogeneous solar cells." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25892.
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This thesis investigates the possibility of enhancing the efficiency of thin film solar cells by including periodic material nonhomogeneities in combination with periodically corrugated back reflectors. Two different types of solar cell are investigated; p-i-n junctions solar cells made from alloys of hydrogenated amorphous silicon (a-Si:H) (containing either carbon or germanium), and Schottky barrier junction solar cells made from alloys of indium gallium nitride (InξGa1-ξN). Material nonhomogeneities are produced by varying the fractions of the constituent elements of the alloys. For example, by varying the content of carbon or germanium in the a-Si:H alloys, semiconductors with bandgaps ranging from 1:3 eV to 1:95 eV can be produced. Changing the bandgap alters both the optical and electrical properties of the material so this necessitates the use of coupled optical and electrical models. To date, the majority of solar cell simulations either prioritise the electrical portion of the simulation or they prioritise the optical portion of the simulation. In this thesis, a coupled optoelectronic model, developed using COMSOL Multiphysics®, was used to simulate solar cells: a two-dimensional finite-element optical model, which solved Maxwell's equations throughout the solar cells, was used to calculate the absorption of incident sunlight; and a finite-element electrical drift-diffusion transport model, either one- or two-dimensional depending on the symmetries of the problem, was used to calculate the steady state current densities throughout the solar cells under external voltage biases. It is shown that a periodically corrugated back reflector made from silver can increase efficiency of an a-Si:H alloy single p-i-n junction solar cell by 9:9% compared to a baseline design, while for a triple junction the improvement is a relatively meagre 1:8%. It is subsequently shown that the efficiency of these single p-i-n junction solar cells with a back reflector can be further increased by the inclusion of material nonhomogeneities, and that increasing the nonhomogeneity progressively increases efficiency, especially in thicker solar cells. In the case of InξGa1-ξN Schottky barrier junction solar cells, the gains are shown to be even greater. An overall increase in efficiency of up to 26:8% over a baseline design is reported.
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Ponton, Simon. "Dépôt chimique en phase vapeur de silice amorphe en tant que revêtement barrière pour flacons pharmaceutiques." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0040.
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L’élaboration de nouvelles solutions médicamenteuses par les laboratoires pharmaceutiques est intimement liée à la maitrise de leurs interactions avec la surface des emballages primaires en verre, afin d’assurer la préservation du principe actif. Sans cet effort, les instances de santé américaine (FDA) et européenne (EMA) ont révélé dès 2007, des altérations irréversibles du médicament et du contenant. Les conséquences sont catastrophiques, les molécules contenues dans le flacon sont dénaturées et deviennent inefficaces, et la surface du verre se délamine en générant des particules insolubles de taille micrométrique en solution. Cette thèse concerne l’étude de revêtements de silice amorphe susceptibles d’être appliqués sur la surface interne de flacons pharmaceutiques pour limiter leur réactivité avec le contenu. Les revêtements ont été élaborés par dépôt chimique en phase gazeuse (CVD), à partir de tétraethylorthosilicate (TEOS) et dioxygène à pression subatmosphérique, entre 350 et 570 °C. Le procédé permet le contrôle des vitesses de dépôt dans la géométrie 3D du flacon, tout en offrant une fenêtre de températures de traitement compatible avec sa tenue mécanique. Une approche pluridisciplinaire qui combine science des matériaux et génie des procédés est mise en œuvre, dans le but de maîtriser les propriétés physico-chimiques et fonctionnelles du revêtement et du procédé d’élaboration. Des dépôts sur substrats plans ont permis d’effectuer une étude croisée de la structure, de la composition et de la densité du film, mettant en œuvre les spectrométries FTIR et ellipsométrique et des techniques d’analyse par faisceau d’ions. Des revêtements peu hydratés, peu poreux et légèrement sous-stœchiométriques en oxygène sont élaborés à 550 °C. Leur valeur de P-etch est 10 Å.s-1 traduisant une bonne résistance à l’érosion. Un modèle cinétique apparent est développé pour la simulation du procédé de dépôt. Il considère deux espèces intermédiaires, impliqués dans deux réactions homogènes et deux hétérogènes. Il reproduit la vitesse de dépôt et sa répartition sur la surface des substrats. Des revêtements de silice amorphe sont déposés dans des flacons en verre et le procédé est simulé numériquement. La prise de masse prédite par la simulation correspond à celle mesurée expérimentalement. Les flacons revêtus sont soumis à un essai de vieillissement hydrothermal lors d’un cycle de stérilisation pendant une heure à 121 °C et 1220 hPa en contact avec de l’eau ultra-pure, suivant la préconisation USP <660>. Ils présentent une excellente résistance hydrolytique, le revêtement empêché le relargage de substances minérales du verre au contact de l’eau. Ce travail ouvre la voie à l’élaboration, par un procédé industrialisable, de revêtements plus denses, susceptibles de remplir les exigences sévères de résistance à l’altération des solutions USP <1660>The development of new pharmaceutical solutions is intimately linked to the control of theirinteractions with the surface of the primary glass packaging, with the aim to ensure thepreservation of the active agent. Already in 2007, the American (FDA) and European (EMA) healthauthorities revealed irreversible alterations between the contained solution and the container. Theconsequences are catastrophic, since the contained active molecules are denatured and becomeineffective, and the surface of the glass delaminates and results in suspension of micrometricsized insoluble particles in the pharmaceutical solution. This thesis focuses on the development ofamorphous silica coatings likely to be applied on the inner surface of pharmaceutical vials to limittheir reactivity with the contained solution. The coatings were processed by chemical vapordeposition (CVD) from tetraethylorthosilicate (TEOS) and dioxygen at subatmospheric pressure,between 350 and 570 °C. The process allows control of the deposition rates in the 3D geometry ofthe vials and at the same time, it operates in a temperature window that is compatible with themechanical integrity of the vial. A multidisciplinary approach, combining materials science andprocess engineering is applied, in order to control the physicochemical and functional properties ofthe coating and its deposition process. Deposition on flat substrates allowed performing a crosslinked investigation of the structure, the composition and the density of the films by FTIR andellipsometric spectroscopies and ion beam analysis techniques. Poorly hydrated, non-porous andslightly lower than SiO2 stoichiometry coatings were processed at 550 °C. Their P-etch value is 10Å.s-1, indicating a good erosion resistance. An apparent kinetic model is developed for thesimulation of the deposition process. It considers two intermediate species, involved in twohomogeneous and two heterogeneous reactions. It reproduces the deposition rate and itsdistribution over the substrates surface. Amorphous silica coatings are deposited on the internalsurface of glass vials and the deposition process is numerically simulated. The simulation predictsa mass gain that corresponds to the one experimentally determined. The coated vials are filledwith ultra-pure water and are subjected to a hydrothermal aging test with a sterilization cycleduring one hour at 121°C and 1220 hPa according to the USP <660> recommendation. Theypresent an excellent hydrolytic resistance, corresponding to the resistance of the glass to therelease of soluble mineral substances into water. This work paves the way towards theprocessing, through an industrial transferrable process, of denser coatings which are expected tomeet severe specifications compatible with the USP <1660> recommendations
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Polischuk, Vladimir. "Etude et réalisation de structure à base de silicium poreux en vue de la détection de gaz." Ecully, Ecole centrale de Lyon, 1999. http://www.theses.fr/1999ECDL0016.
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Ce travail de thèse visait à étudier les potentialités du silicium poreux comme support d'un élément sensible pour les capteurs de gaz. Afin de comprendre les mécanismes de formation du silicium poreux nous avons eu recours à l'électrochimie fondamentale de silicium. Ainsi, les mesures I-V de l'interface silicium/solution d'acide fluorhydrique ont mis en évidence deux mécanismes compétitifs : la formation électrochimique de l'oxyde de silicium et sa dissolution par HF. De même, la nature de l'oxyde de silicium est discutée dans le cadre des diagrammes d'équilibres tension-ph du système silicium-eau. Dans le but de développer de nouveaux capteurs de gaz, nous avons élaboré des couches de silicium poreux modifiées ultérieurement par un métal catalytique. Dans le cas des structures de type diode (Pd/Sp/Si), l'épaisseur de la couche de silicium poreux contrôle les processus de transport de courant. La quantité du palladium déposée influe beaucoup sur la sensibilité des structures sous gaz. Ainsi, ce sont les structures avec une couche ultramince de palladium qui présentent les meilleures réponses à l'hydrogène. En s'appuyant sur le modelé d'une hétérojonction métal/silicium poreux/si ayant une couche mince de silicium poreux, nous avons relie ce phénomène a la variation des porteurs libres de la zone de charge d'espace du silicium. La mesure de la différence de potentiel de contact nous a permis d'étudier l'effet de l'adsorption d'hydrogène sur la surface de palladium supporte sur du silicium poreux. Malgré nos attentes, les structures a base du silicium poreux ont montré une faible amélioration de la sensibilité par rapport aux structures traditionnelles Pd/SiO2/Si. Par contre, elles étaient plus performantes en ce qui concerne la cinétique, donc le temps de réponse deux fois plus rapide.
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Vick, Andrew James. "Measuring low dimensional Schottky barriers of rare earth silicide-silicon interfaces." Thesis, University of York, 2011. http://etheses.whiterose.ac.uk/2436/.
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The focus of this study is the measurement of low dimensional Schottky barrier heights of metal silicide-silicon interfaces and the challenges of current-voltage (I/V) curve interpretation. Engineering the Schottky barrier to exploit the spin and charge of an electron and manipulate it through silicon requires careful control ofthe interface structure between the metal and the silicon substrate. In doing this the advantages of both magnetic materials and semiconductors can be combined in spintronics. Current-voltage characteristics have been taken using contact probe techniques, and from these the Schottky barrier properties have been extracted using standard Schottky barrier models. Several ways of extracting the Schottky barrier height have been explored concluding with the development of a new fitting program which utilises the whole data set and includes additional factors such as image force lowering and an oxide tunnel barrier. Nickel silicide thin films on silicon(111) have been used as a test system to develop the analysis for IN measurements. Rare earth silicides were grown on silicon(111) and silicon(OO 1) forming ordered interface structures, which have been extensively studied in the group at York. The rare earth silicides on silicon have attractive low Schottky barrier heights (0.4 eV). Erbium silicide islands of the order of 500 nm diameter were grown on silicon (111) and erbium silicide nanowires were grown on silicon (001) 4° offcut. Using an Omicron Nanoprobe contacts were made with the nano structures enabling the measurement of the electrical properties of the silicide and the Schottky barrier between the silicide island and the substrate. A new growth study of manganese on erbium silicide on silicon(111) is presented as a possible way to engineer the Schottky barrier between a ferromagnetic material and silicon. Preliminary results of the IN measurement are presented and the additional complication of an oxide layer highlighted. If engineering the Schottky barrier in this way is successful, the realisation of spintronics maybe a step closer.
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Markevich, Alexander. "Ab-initio calculations of diffusion barriers of small vacancy clusters in silicon." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/2288.
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Mestrado em Ciência e Engenharia de MateriaisEsta tese apresenta os resultados de um programa de investigação sobre a difusão da lacuna, bi-lacuna e tri-lacuna em silício utilizando simulações numéricas pelo método da teoria do funcional da densidade. Este método está implementado na forma de um programa informático referido como AIMPRO (Ab Initio Modelling PROgram). Para o cálculo dos pontos cela dos mecanismos de difusão foi usado o método “Nudged Elastic Band”. As condições fronteira dos problemas foram impostas recorrendo à utilização de agregados esféricos de silício com 275 atomos, cuja superfície foi saturada por ligações Si-H. As lacunas foram então introduzidas no centro destes agregados. Os valores calculados das barreiras de difusão para a lacuna simples e para a bi-lacuna são respectivamente 0.68 e 1.75 eV. Estes valores apresentam um acordo razoável com os obtidos experimentalmente e obtidos em outros cálculos anteriores. A barreira de difusão da tri-lacuna foi, de acordo com a literatura disponível, calculada pela primeira vêz. O mecanismo de difusão mais favorável apresenta uma barreira de 2.2 eV. No seguimento dos resultados para a lacuna e bi-lacuna, pensamos que este resultado sobrestima a barreira em cerca de 0.25 eV, colocando a nossa melhor estimativa em 1.9- 2.0 eV. Varias fontes de erro nos resultados são comentadas, assim como são sugeridas várias formas de as evitar. ABSTRACT: This work presents the results of a computational investigation into the diffusion of the single vacancy (V) and small vacancy clusters, divacancy (V2) and trivacancy (V3), in silicon. The calculations were performed principally using local density functional theory as implemented by the AIMPRO (Ab Initio Modelling PROgram) code. The Nudged Elastic Band Method was used for elucidating diffusion paths and obtaining the energy barriers for diffusion of the defects considered. Based on ab-initio calculations with H-terminated Si clusters with 275 host atoms, diffusion paths for neutral Vn (n = 1 to 3) defects were found. Calculated values of the activation energy for the diffusion of the Si vacancy and divacancy are 0.68 and 1.75 eV, respectively. These values are in a reasonable agreement with those derived from experimental and previous ab-initio modelling studies. The diffusion of trivacancy in Si has been modelled for the first time. The diffusion barrier of V3 along the proposed diffusion path was found to be about 2.2 eV. This result comes overestimated as the experimental data indicates that the values of diffusion barriers for divacancy and trivacancy in Si should be similar. Probable sources of the calculation errors have been considered and possible ways to surmount these difficulties are proposed.
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Matic, Nikola. "SURFACE SCIENCE ASPECTS OF ELECTROCATALYSIS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1397794046.
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Abusch-Magder, David 1969. "Artificial atoms and electron puddles : single and double barriers in a silicon MOS system." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10184.
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Hübner, René. "Dünne tantalbasierte Diffusionsbarrieren für die Kupfer-Leitbahntechnologie: Thermische Stabilität, Ausfallmechanismen und Einfluss auf die Mikrostruktur des Metallisierungsmaterials." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1102329038515-23539.
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Aufgrund der höheren elektrischen Leitfähigkeit und des größeren Widerstandes gegen Elektromigration im Vergleich zum Aluminium wird seit einigen Jahren Kupfer als Leitbahnmaterial in der Mikroelektronik eingesetzt. Da Kupfer jedoch eine hohe Beweglichkeit in den für die Halbleitertechnologie relevanten Werkstoffen aufweist, sind zur Verhinderung einer Diffusion effektive Barrieren notwendig. Dabei muss die u. a. geforderte hohe thermische Stabilität der Barrierematerialien auch im Zuge der fortschreitenden Miniaturisierung der mikroelektronischen Bauelemente und damit der Reduzierung der Barriereschichtdicken sichergestellt sein. Im Rahmen der Arbeit wurden mittels Magnetron-Sputtern neben Ta- und TaN-Einfachschichten sowie Ta-TaN-Mehrfachschichten auch Ta-Si-N-Einfachschichten jeweils mit und ohne Cu-Metallisierung sowohl auf blanke als auch auf thermisch oxidierte Si-Scheiben abgeschieden. Die Dicken der Barriereeinzelschichten und die der Cu-Schichten betrugen 10 nm bzw. 50 nm. Die Beurteilung der Barrierestabilität sowie die Charakterisierung der Ausfallmechanismen erfolgten nach Wärmebehandlungen durch den kombinierten Einsatz von Röntgenstreumethoden, spektroskopischen sowie mikroskopischen Analyseverfahren. In Abhängigkeit von ihrer Zusammensetzung und damit von der Mikrostruktur im Ausgangszustand finden für die zwischen Kupfer und SiO2 abgeschiedenen Diffusionsbarrieren unterschiedliche Prozesse während thermischer Belastungen statt. Bei den mehrstufigen Ta-TaN-Barrieren setzt bereits bei T = 300 °C eine Umverteilung von Stickstoff ein, die bei T = 500 °C in der Bildung von Ta2N-Kristalliten resultiert. Im Fall der Ta-Si-N-Barrieren führt die vorhandene Cu-Metallisierung zu einer an der Cu/Barriere-Grenzfläche beginnenden Kristallisation. Dabei hängen sowohl deren Einsatzzeitpunkt während einer bei konstanter Temperatur durchgeführten Wärmebehandlung als auch das entstehende Kristallisationsprodukt von der Barrierezusammensetzung ab. Im Zuge der Kristallisation erfolgt die vollständige Zerstörung der ursprünglichen Schichtintegrität, so dass Kupfer in unmittelbaren Kontakt zum SiO2-Substrat gelangt. Der sensitive Nachweis einer Cu-Diffusion durch die Barriere erfolgte einerseits durch die Charakterisierung von Cu/Barriere/SiO2/Si-Systemen mit Hilfe spurenanalytischer Methoden und andererseits durch die Untersuchung von Proben mit geändertem Aufbau. Durch Abscheidung der Barrieren zwischen Kupfer und Silizium ist mittels Röntgenbeugung die nach Diffusion von Cu-Atomen ins Substrat einsetzende Bildung von Cu3Si detektierbar. Mit den kritischen Temperaturen für die Bildung dieses Kupfersilizids erfolgte die vergleichende Bewertung der thermischen Stabilitäten der Barrieren. Werden die dünnen Ta-basierten Schichten zusätzlich bezüglich ihres spezifischen elektrischen Widerstandes beurteilt, so stellt sich eine Ta56Si19N25-Diffusionsbarriere als am geeignetsten für den Einsatz in Cu-Metallisierungssystemen heraus. Die mikrostrukturellen Untersuchungen gestatten Aussagen zu den Versagensmechanismen der einzelnen Barrieren. Für die Ta-TaN-Mehrfachschichten wird durch die einsetzende Stickstoffumverteilung und die sich anschließende Ta2N-Bildung bereits frühzeitig die stabile Mikrostruktur der TaN-Schicht zerstört. Während für Ta-Si-N-Schichten mit einem N-Gehalt von bis zu 25 at.% eine Cu-Diffusion ins Substrat erst nach vorzeitiger Barrierekristallisation beobachtet wird, erfolgt sie im Fall der stickstoffreichen Ta-Si-N-Barrieren in einem Zustand, für den mittels Röntgenbeugung eine Kristallisation noch nicht nachweisbar ist. Die Untersuchung der Abhängigkeit der sich während des Cu-Schichtwachstums bzw. einer nachträglichen Wärmebehandlung ausbildenden Cu-Texturkomponenten von der chemischen Zusammensetzung der Unterlage erfolgte mittels röntgenographischer Texturanalyse. Zur Diskussion der beobachteten Vorzugsorientierungen wurde das Modell des zweidimensionalen Kornwachstums in dünnen Schichten herangezogen.
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Guicheteau, Rudy. "Elaboration et étude des conditions de mise en forme de poudres composites métalliques pour des pièces industrielles à vocation électromagnétiques." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0012/document.
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Le développement des moteurs électromagnétiques nécessite des matériaux magnétiques possédant une forte induction à saturation, une perméabilité magnétique importante, ainsi que de faibles pertes magnétiques lorsque le matériau est utilisé à des fréquences allant jusqu’à 20 kHz.Pour réduire ces pertes, le matériau doit alors posséder une résistivité électrique la plus élevée possible. Les composites magnétiques doux ont été développés dans ce contexte, en associant du fer (ou un alliage) à un matériau isolant. Historiquement, ceux-ci étaient présents sous forme de couches laminées, mais des matériaux coeur-écorce se sont développés ces dernières années.Au cours de ces travaux, nous avons développé l’enrobage de particules de fer par un matériau isolant et magnétique : le ferrite NiZn. L’enrobage de ferrite a été réalisé par voie liquide. De cette manière, il a été possible de réaliser un enrobage homogène d’épaisseur contrôlée sur des particules de fer sphériques.L’étude de la mise en forme de ces particules coeur-écorce, par métallurgie des poudres, a montré qu’en frittant le matériau composite à une température supérieure à 580°C, une réaction d’oxydoréduction a lieu entre les deux composés. Cette réaction mène à la formation d’une phase type FexNi1-x et d’une solution solide FeO-FeZnO. Ces deux phases font alors chuter les propriétés magnétiques du matériau final.Pour éviter cette réaction d’oxydoréduction, nous avons montré qu’il est possible d’ajouter une barrière de diffusion : la silice, ou bien de fritter le matériau à l’aide de techniques type FAST. De cette manière, nous avons obtenu un matériau possédant des pertes magnétiques comparables à celles de poudres industrielles mais avec une perméabilité magnétique supérieureMagnetic materials with high saturation induction, high magnetic permeability and low magnetic losses, are necessary for the development of electromagnetic motors used at frequencies up to 20 kHz.The electric resistivity of these materials must be as high as possible to reduce iron losses. To increase the resistivity of ferromagnetic materials, soft magnetic composites (SMC) were developed combining a ferromagnetic material with an insulating one. Firstly, laminated steel sheets were developed but during the last years core-shell materials were investigated.In this work, we have studied the coating of iron particles by an insulating and a magnetic material: NiZn ferrite. These coatings were deposited by an aqueous solution to obtain a homogenous coating with a controlled thickness on spherical iron particles.A study of composite shaping by powder metallurgy shows a redox reaction between ferrite and iron at a sintering temperature above 580°C. This reaction leads to the formation of a FexNi1-x and a FeO-FeZnO solid solution. These two phases deteriorate the magnetic properties of the final material.To avoid this redox reaction, we have shown that a silica layer can be used as a diffusion barrier. Another solution is to sinter the composite with a Field Assisted Sintering Technique (FAST) as Spark Plasma Sintering. A material with properties similar to industrial material and with a superior magnetic permeability was obtained with Spark Plasma Sintering
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Zhao, Xiaopeng. "Tantalum- and ruthenium-based diffusion barriers/adhesion promoters for copper/silicon dioxide and copper/low κ integration." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4672/.
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The TaSiO6 films, ~8Å thick, were formed by sputter deposition of Ta onto ultrathin SiO2 substrates at 300 K, followed by annealing to 600 K in 2 torr O2. X-ray photoelectron spectroscopy (XPS) measurements of the films yielded a Si(2p) binding energy at 102.1 eV and Ta(4f7/2) binding energy at 26.2 eV, indicative of Ta silicate formation. O(1s) spectra indicate that the film is substantially hydroxylated. Annealing the film to > 900 K in UHV resulted in silicate decomposition to SiO2 and Ta2O5. The Ta silicate film is stable in air at 300K. XPS data show that sputter-deposited Cu (300 K) displays conformal growth on Ta silicate surface (TaSiO6) but 3-D growth on the annealed and decomposed silicate surface. Initial Cu/silicate interaction involves Cu charge donation to Ta surface sites, with Cu(I) formation and Ta reduction. The results are similar to those previously reported for air-exposed TaSiN, and indicate that Si-modified Ta barriers should maintain Cu wettability under oxidizing conditions for Cu interconnect applications. XPS has been used to study the reaction of tert-butylimino tris(diethylamino) tantalum (TBTDET) with atomic hydrogen on SiO2 and organosilicate glass (OSG) substrates. The results on both substrates indicate that at 300K, TBTDET partially dissociates, forming Ta-O bonds with some precursor still attached. Subsequent bombardment with atomic hydrogen at 500K results in stoichiometric TaN formation, with a Ta(4f7/2) feature at binding energy 23.2 eV and N(1s) at 396.6 eV, leading to a TaN phase bonded to the substrate by Ta-O interactions. Subsequent depositions of the precursor on the reacted layer on SiO2 and OSG, followed by atomic hydrogen bombardment, result in increased TaN formation. These results indicate that TBTDET and atomic hydrogen may form the basis for a low temperature atomic layer deposition (ALD) process for the formation of ultraconformal TaNx or Ru/TaNx barriers. The interactions of sputter-deposited ruthenium with OSG at 300 K have been studied by XPS for Ru coverages from ~ 0.1 monolayer to several monolayers, using in-situ sample transfer between the deposition and analysis chambers. The results indicate Stranski-Krastanov (SK) type growth, with the completion of the first layer of Ru at an average thickness corresponding to 1 monolayer average coverage. Ru(0) is the only electronic state present. XPS core level spectra indicate weak chemical interactions between Ru and the substrate. A less pronounced tendency towards SK growth was observed for Ru deposition on parylene. Deposition of Ru on OSG followed by electroless deposition of Cu resulted in the formation of a shiny copper film that failed the Scotch® tape test. Results indicate failure mainly at the Ru/OSG interface.
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Baniahmad, Ata. "QUANTUM MECHANICAL Study and Modelling of MOLECULAR ELECTRONIC DEVICES." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13193/.
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Molecular electronics pursues the use of molecules as fundamental electronic components. The inherent properties of molecules such as nano-size, low cost, scalability, and self-assembly are seen by many as a perfect complement to conventional silicon electronics. Molecule based electronics has captured the attention of a broad cross section of the scientific community.
In molecular electronic devices, the possibility of having channels that are just one atomic layer thick, is perhaps the most attractive feature that takes the attention to graphene.The conductivity, stability, uniformity, composition, and 2D nature of graphene make it an excellent material for electronic devices.
In this thesis we focused on Zigzag Graphene NanoRibbon(ZGNR) as a transmission channel. Due to the importance of an accurate description of the quantum effects in the operation of graphene devices, a full-quantum transport model has been adopted: the electron dynamics has been described by Density Functional Theory(DFT) and transport has been solved within the formalism of Non-Equilibrium Green’s Functions (NEGF). Using DFT and NEGF methods, the transport properties of ZGNR and ZGNR doped with Si are studied by systematically computing the transmission spectrum. It is observed that Si barrier destroyed the electronic transport properties of ZGNR, an energy gap appeared for ZGNR, and variations from conductor to semiconductor are displayed. Its followed by a ZGNR grown on a SiO2 crystal substrate, while substituting the Graphene electrodes with the Gold ones, and its effect on transmission properties have been studied. Improvement in transmission properties observed due to the formation of C-O bonds between ZGNR and substrate that make the ZGNR corrugated. Finally, we modeled a nano-scale Field Effect Transistor by implementing a gate under SiO2 substrate. A very good I-ON/I-OFF ratio has been observed although the device thickness.
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Silva, Júlio Batista Rodrigues da. "Fabricação e caracterização de detector de Barreira de superfície a partir de substrato de silício comercial." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-27062016-144119/.
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Neste trabalho foram desenvolvidos detectores de radiação Barreira de superfície de silício que fossem capazes de detectar a presença da radiação gama de baixa energia proveniente de sementes de iodo-125 utilizada em tratamentos de braquiterapia. A partir de substratos comerciais de silício foram desenvolvidos os detectores, de uma sequência que partiu de tratamentos químicos nas superfícies destes substratos com a intenção de minimizar os possíveis ruídos gerados, validação das amostras obtidas como diodos, assegurando características detectoras, e a efetiva utilização como detector para fontes radioativas de iodo-125 com energia em torno de 25 kev e amerício-251 com energia na ordem de 59 kev. Finalizou realizando a análise dos espectros de energia obtidos e assim foi possível observar a capacidade destes detectores para mensuração da energia proveniente destas sementes.In this work it was developed radiation detectors silicon surface barrier that were capable of detecting the presence of gamma radiation from a low energy of iodine-125 seeds used in brachytherapy treatments. From commercial silicon substrates detectors were developed, one sequence left of chemical treatments to the surfaces of these substrates with the intention of minimizing the possible noise generated, validation of the samples obtained as diodes, ensuring detector characteristics and effective use as detector for iodine-125 radioactive sources with energy of about 25 kev and americium-251 with energy on the order of 59 kev. Finished performing the analysis of the obtained energy spectra and so it was possible to observe the ability of these detectors to measure the energy from these seeds.
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Chevalier, Florian. "Conception, fabrication et caractérisation de transistors à effet de champ haute tension en carbure de silicium et de leur diode associée." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-01016687.
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Dans le contexte des transports plus électriques, les parties mécaniques tendent à être remplacées par leurs équivalents électriques plus petits. Ainsi, le composant lui-même doit supporter un environnement plus sévère et de lourdes contraintes (haute tension, haute température). Les composants silicium deviennent alors inappropriés. Depuis la commercialisation des premières diodes Schottky en 2001, le carbure de silicium est le matériau reconnu mondialement pour la fabrication de dispositifs haute tension avec une forte intégration. Sa large bande d'énergie interdite et son fort champ électrique critique permettent la conception de transistors à effet de champ avec jonction (JFET) pour les hautes tensions ainsi que les diodes associées. Les structures étudiées dépendent de nombreux paramètres, et doivent ainsi être optimisées. L'influence d'un paramètre ne pouvant être isolée, des méthodes mathématiques ont été appelées pour trouver la valeur optimale. Ceci a conduit à la mise en place d'un critère d'optimisation. Ainsi, les deux grands types de structures de JFET verticaux ont pu être analysés finement. D'une part, la recherche d'une structure atteignant les tensions les plus élevées possible a conduit à l'élaboration d'un procédé de fabrication complexe. D'autre part, un souci de simplification et de stabilisation des procédés de fabrication a permis le développement d'un composant plus simple, mais avec une limite en tension un peu plus modeste.
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Tsai, Yi-Heng, and 蔡宜恒. "Effects of Silicon Oxide Barrier Layers on Silicon Nanocrystal Thin Films." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/07229706024000460088.
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碩士國立交通大學
光電工程學系
99
In order to achieve low cost and high efficiency solar cells, all silicon tandem solar cells made of Si nanocrystal (Si NC) thin films with different bandgaps (such as Si/SiO2 Si NC thin films) stacking on crystalline Si solar cells are proposed. The solar cells can greatly reduce thermalization loss. However, Si/SiO2 Si NC thin films exhibit low conductivity because of poor conductivity of SiO2 barrier layers. In this thesis, we created additional transportation paths by increasing the defects of barrier layers. We studied effects of the defects on the crystallization and dimension of Si NC thin films by Raman spectra and XRD. In addition, we analyzed the influences of the defects on optical properties of Si NC thin films by PL spectra. Finally, we discussed a possible carrier transportation mechanism from electrical results.
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Chang, Wei, and 章緯. "Schottky Barrier Silicon Nanowire SONOS Flash Memory." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/02018208850287818702.
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博士國立清華大學
電子工程研究所
100
Silicon nanowire has attracted a growing interest from semiconductor industry to replace the bulk Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) memory in future cell scaling, system-on-chip, system-on-panel, and 3D integration applications. However, a relatively high gate voltage is still required for the conventional nanowire SONOS cell during programming or erasing. Aggressive scaling of operation voltage is much preferred to improve cell speed, energy dissipation, periphery circuitry, and cell reliability for the use in practical embedded or mobile applications. This dissertation presents an innovative Schottky barrier Silicon nanowire charge-trapping SONOS Flash memory cell, and performs a thorough study of its operations for use in future nonvolatile memory cell. Real silicon cell fabrications and in-depth measurements are performed to examine the programming, erasing and reading operations of this new memory cell incorporated with thermal retention and cycling reliability characterizations. By applying Schottky barrier source/drain to enhance electrical field in silicon gate-all-around nanowire, the nonvolatile Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) memory can operate at a gate voltage of 5 to 7V for programming, and -7 to -9V for erasing through Fowler-Nordheim tunneling. The larger gate voltage is, the faster programming/erasing speed and wider threshold-voltage shift are attained. Importantly, the Schottky barrier nanowire SONOS cells exhibit superior 100K cycling endurance and high-temperature retention without any damages from metallic silicidation process or field-enhanced tunneling. In addition, a localized programing and erasing scheme can be utilized to enhance the threshold voltage shift window in this Schottky barrier nanowire SONOS cell. The breakthrough in low-voltage programming and erasing operations with simple silicidation process make the Schottky barrier silicon nanowire SONOS cell very promising in future 3D integration, system-on-chip, and system-on-panel applications.
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Chen, Chih-Hung, and 陳致宏. "Study on Amorphous Silicon Carbide Barrier Dielectric Materials." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/94551691489117542359.
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碩士國立中山大學
物理學系研究所
90
In the generation of deep submicron semiconductor fabrication，transmission delay is primarily caused by the parasitic resistance and capacitance (RC) in the multilevel interconnects. Besides，electromigration is also a serious issue for the reliability of devices . There are two principle methods of reducing the RC delay. The first method is to replace the Al wires with Cu interconnects which supply lower resistivity and high resistance to electromigration. The second method is to use a lower dielectric constant material as the inter-metal dielectric. But in Copper metallization，the key issue of this technology is the formation of a thin barrier layer for Cu on the surface of the SiC film to prevent the absorption of water and diffusion of Cu. In this study，we employed films SiC base compounds to investigate their chemical bonds, I-V characteristics comparisons with Al and Cu gate. On the other hand, because of serious C-V hysteretic phenomena, we try to analyze and build up models. There five models is reasonable for our experiment: (1) mobile ions, (2) dielectric polarization, (3) carrier injection, (4) gate-electrons injection, and (5) bound charges. They happens in different materials and structures.
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WU, BING-SHENG, and 吳炳昇. "Fabrication and characterization of amorphous silicon bulk barrier phototransistors." Thesis, 1985. http://ndltd.ncl.edu.tw/handle/33237063455459934713.
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