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1

Chen, B. P. T. "Deposition and material characterisation of alternative high-K gate oxides." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597522.

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This thesis investigates the relation between the growth process, structure and properties of three potential high dielectric constant (high-K) gate oxides as replacements for silicon dioxide (SiO2) in Complementary Metal-Oxide-Semiconductor (CMOS) process. Production of high quality high-K gate oxides requires optimisation of the deposition conditions. Zirconium dioxide (ZrO2), yttria-stabilised ZrO2 (YSZ) and hafnium oxide (HfO2) films have been deposited using reactive radio-frequency (RF) magnetron sputtering in an Oxygen (O2)/ Argon (Ar) mixture at room temperature. The as-deposited film properties are quite comparable to those reported in the literature. ZrO2 exhibits a refractive index (R.I.) of 2.03, a bandgap of 5.8 eV, a dielectric constant of 26.2 and average breakdown field strength of 5.2 MV/cm. YSZ has a R.I. of 2.19, a bandgap of 5.6 eV, a dielectric constant of 27 and average breakdown field strength of 5.4 MV/cm. HfO2 possesses a R.I. of 2.1, a bandgap of 6 eV, a dielectric constant of 25 and average breakdown field strength of 5.4 MV/cm. Although the film qualities of all three oxide systems are similar, the research demonstrated that HfO2 is a better candidate to succeed thermal oxide as alternative gate dielectrics because the leakage current of HfO2 is at least seven orders in magnitude lower than that of using pure silicon oxide with identical equivalent oxide thickness (EOT). Electron Spin Resonance (ESR) studies of ZrO2 and YSZ films showed that defect trapping centres existed in the dielectrics. Initial investigation on potential metal nitride electrodes showed that surface oxidation is a major concern. This may be caused by exposure to air during the transfer to X-ray Photoelectron Spectroscopy (XPS) system or problems in the deposition procedure. The Ultraviolet Photoelectron Spectroscopy (UPS) analysis of the metal nitride reflects the material dependence of the work function and may be used as a guide in the future development of a suitable metal electrode.
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2

Wang, Jiahui. "High-K Material Based Leaky-wave Antenna Design, Implementation, and Manufacture." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347582062.

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3

Li, Wenmei. "CHARACTERIZATION OF HIGH-K GATE STACKS IN METAL-OXIDE-SEMICONDUCTOR CAPACITORS." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010202-100109.

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The purpose of this research has been to use off-line characterization techniques to establish material-specific properties of gate-stack constituents (i.e., high-k dielectric stacks and electrodes) and complete gate-stack structures. Hence, the characterization methodologies were established to evaluate high-k dielectrics at various processing levels, which, in part, determine the final characteristics of an advanced gate-stack device. Material systems that were investigated include: Al-O, Hf-Si-O, Zr-Si-O, Ti-O, Ta-O and Sr-Ti-O. Various physical and electrical characterization techniques were used to establish fundamental understandings of the materials selected, thin-film growth/deposition processes, and gate-stack structures. General conclusions for stable and unstable gate-dielectric materials have been establishedregarding the presence of a problematic interfacial layer at the Si/dielectric interface, graded dielectric layers, and the stability of gate electrodes on high-k dielectrics.The nanometer-scale chemistry of a gate-stack capacitor whose expected structure is Si/SiOxNy/Ta2O5/TiN/Al was studied by high-resolution electron-energy-loss spectroscopy in a scanning transmission electron microscope. Elemental profiles with near-atomic-level resolution for Si, Ti, N, Al, and O demonstrate that the device structure deviates drastically from the expectation and is chemically complex.It is concluded that the graded distribution of certain elements across the gate-stack capacitor completely precludes a band-structure model that assumes abrupt interfaces and chemically discrete layers. This study impacted on subsequent interpretations of flatband voltage extractions and electrical degradation following backside metallization/postmetallization annealing for capacitors whose dielectric-stack was based on Ta-O.Detailed and extensive electrical characterizations of Pt/SiOx/Sr-Ti-O/Si MOS capacitors were carried out to investigate reliability issues in a bi-layer gate dielectric. Based on these studies, models are proposed to describe the carrier transport and dielectric degradation for a Sr-Ti-O capacitor. It is concluded that conduction is dominated by Frenkel-Poole emission from mid-gap trap levels. The trap barrier height is estimated to be 1.51eV. A model based on the atomic and electronic structure of oxygen vacancies can account for the reported leakage-current characteristics. In addition, it is tentatively proposed that anode-hole injection and hole trapping control the dielectric degradation under gate injection.

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4

Xu, Toby Ge. "Material and array design for CMUT based volumetric intravascular and intracardiac ultrasound imaging." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54861.

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Recent advances in medical imaging have greatly improved the success of cardiovascular and intracardiac interventions. This research aims to improve capacitive micromachined ultrasonic transducers (CMUT) based imaging catheters for intravascular ultrasound (IVUS) and intra-cardiac echocardiography (ICE) for 3-D volumetric imaging through integration of high-k thin film material into the CMUT fabrication and array design. CMUT-on-CMOS integration has been recently achieved and initial imaging of ex-vivo samples with adequate dynamic range for IVUS at 20MHz has been demonstrated; however, for imaging in the heart, higher sensitivities are needed for imaging up to 4-5 cm depth at 20MHz and deeper at 10MHz. Consequently, one research goal is to design 10-20MHz CMUT arrays using integrated circuit (IC) compatible micro fabrication techniques and optimizing transducer performance through high-k dielectrics such as hafnium oxide (HfO2). This thin film material is electrically characterized for its dielectric properties and thermal mechanical stress is measured. Experiments on test CMUTs show a +6dB improvement in receive (Rx) sensitivity, and +6dB improvement in transmit sensitivity in (Pa/V) as compared to a CMUT using silicon nitride isolation (SixNy) layer. CMUT-on-CMOS with HfO2 insulation is successfully integrated and images of a pig-artery was successfully obtained with a 40dB dynamic range for 1x1cm2 planes. Experimental demonstration of side looking capability of single chip CMUT on CMOS system based FL dual ring arrays supported by large signal and FEA simulations was presented. The experimental results which are in agreement with simulations show promising results for the viability of using FL-IVUS CMUT-on-CMOS device with dual mode side-forward looking imaging. Three dimensional images were obtained by the CMUT-on-CMOS array for both a front facing wire and 4 wires that are placed perpendicular to the array surface and ~4 mm away laterally. For a novel array design, a dual gap, dual frequency 2D array was designed, fabricated and verified against the large signal model for CMUTs. Three different CMUT element geometries (2 receive, 1 transmit) were designed to achieve ~20MHz and ~40MHz bands respectively in pulse-echo mode. A system level framework for designing CMUT arrays was described that include effects from imaging design requirements, acoustical cross-talk, bandwidths, signal-to-noise (SNR) optimization and considerations from IC limitations for pulse voltage. Electrical impedance measurements and hydrophone measurements comparisons between design and experiment show differences due to inaccuracies in using SixNy homogenous material in simulation compared to fabricated thin-film stacks (HfO2-AlSi-SixNy). It is concluded that for “thin” membranes the effect of stiffness and mass of HfO2 and AlSi (top electrode) cannot be ignored in the simulation. Also, it is understood that aspect ratio (width to height) <10 will have up to 15% error for center frequency predicted in air when the thin-plate approximation is used for modelling the bending stiffness of the CMUT membrane.
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5

Guerrero, Enriquez Rubén Dario. "Etude des filtres miniatures LTCC High K en bandes L&S." Thesis, Brest, 2016. http://www.theses.fr/2016BRES0036/document.

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Dans les systèmes actuels de communication, qu’ils soient terrestre ou spatial, qu’ils soient mobile ou fixe, il y a un réel intérêt à développer des front-ends radiofréquences et hyperfréquences miniatures et performants. Ceci s’applique en particulier aux dispositifs de filtrage où l’encombrement et les facteurs de qualité sont clairement antagonistes. Pour les bandes de fréquences basses aux alentours du GHz, les longueurs d’onde restent encore importantes, rendant difficiles les efforts de miniaturisation. D’autre part il faut aussi s’assurer que ces filtres viendront s’interconnecter aisément avec les autres composants du système, notamment les actifs.Pour toutes ces raisons, le développement de structures de filtres multicouches utilisant des substrats à haute permittivité (εr = 68) selon une approche LTCC apparait comme une alternative intéressante. Elle peut en effet conduire à une réduction significative de l'empreinte (footprint) sans pour autant trop nuire aux performances électriques.Dans le cadre de ce travail, deux structures de filtres multicouches ont été développées pour répondre à des spécifications proposées en bandes L et S, par un équipementier du spatial. Ces filtres ont pour caractéristiques principales un haut niveau de rejection et des faibles pertes dans la bande passante. Pour atteindre les spécifications, un filtre SIW empilé verticalement et un filtre à stubs en court-circuit en configuration triplaque ont été étudiés. Le filtre SIW se distingue par un facteur de qualité élevé, ce qui entraîne des faibles pertes d’insertion et une bonne platitude. La solution à stub permet quant à elle de réduire l’encombrement mais au prix d’un impact sur les performances électriques. Dans les deux cas on tire parti de la souplesse offerte par la technologie LTCC, puisqu’elle offre finalement un degré de liberté supplémentaire, par rapport à une approche planaire classique. Si dans le cas SIW, c’est surtout l’architecture topologique qui a été étudiée finement pour pouvoir agencer et coupler douze cavités, dans le cas du filtre à stub une synthèse mettant à profit tous les degrés de liberté offerts a été spécifiquement développée.Compte tenu de la complexité des filtres, notamment à cause de l’ordre élevé et de la mise en oeuvre de murs « électriques » à partir d’arrangements de via spécifiques, une attention particulière doit être apportée lors des phases de simulation et d’optimisation. De plus la très forte permittivité du substrat ne permet pas d’utiliser de ligne 50 Ohms. Enfin les transitions constituent un point dur de l’exercice surtout dans le cas SIW.Cette thèse co-financée par le CNES (Centre National d'Etudes Spatiales) et Thales Alenia Space, était accompagnée par un projet R&T financé par le CNES. Le fondeur allemand Via Electronic avait en charge la fabrication des filtres
In current communication systems, whether terrestrial or spatial, whether fixed or mobile, there is a real interest in developing high performance miniature RF front-ends. This is applied in particular to filter devices, in which the size and the quality factors are clearly in conflict. For low frequency bands around the GHz, the wavelengths remain significant, making it difficult the miniaturization efforts. On the other hand, we must also ensure that these filters will be easily interconnected with other other system components, including active devices.For all these reasons, the development of multilayer filter structures using high permittivity substrates (Er = 68) in an LTCC approach is consolidated as an interesting alternative. It may lead to a significant footprint reduction without decreasing the electrical performances.As part of this work, two multilayer filter structures have been developed to meet the given specifications in L and S bands, given by a space manufacturer. These filters have as main features a high rejection level and low losses in the passband. To meet the specifications, a vertically stacked SIW filter and a short-circuited stubs filter in a stripline configuration were studied. The SIW filter is characterized by a high quality factor, which results in low insertion loss and good flatness. The stubs filter allows in contrast to reduce the footprint but at the price of impacting the electrical performance. In both cases we take advantage of the flexibility offered by the LTCC technology as it finally provides an additional freedom degree compared to a conventional planar approach. For the SIW filter, the topological architecture was studied and designed in detail, to be able to arrange and synthetize couplings between twelve cavities. In a similar way, for the stub filter a synthesis that takes profit of all the offered freedom degrees was developed.Given the filters complexity, especially due to the high order and the implementation of “electrical walls" based on specific vias patterns, a close attention must be paid during the simulation and optimization phase. In addition, the high permittivity substrate does not allow to conceive 50-Ohms lines. Finally, access transitions constitute a challenging task, especially for the SIW case.This thesis was co-funded by CNES (Centre National d'Etudes Spatiales) and Thales Alenia Space, and was accompanied by an R&T project funded by CNES. The German foundry Via Electronic was responsible for the filters fabrication
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6

Tewg, Jun-Yen. "Zirconium-doped tantalum oxide high-k gate dielectric films." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/1346.

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A new high-k dielectric material, i.e., zirconium-doped tantalum oxide (Zr-doped TaOx), in the form of a sputter-deposited thin film with a thickness range of 5-100 nm, has been studied. Important applications of this new dielectric material include the gate dielectric layer for the next generation metal-oxide-semiconductor field effect transistor (MOSFET). Due to the aggressive device scaling in ultra-large-scale integrated circuitry (ULSI), the ultra-thin conventional gate oxide (SiO2) is unacceptable for many practical reasons. By replacing the SiO2 layer with a high dielectric constant material (high-k), many of the problems can be solved. In this study, a novel high-k dielectric thin film, i.e., TaOx doped with Zr, was deposited and studied. The film’s electrical, chemical, and structural properties were investigated experimentally. The Zr dopant concentration and the thermal treatment condition were studied with respect to gas composition, pressure, temperature, and annealing time. Interface layer formation and properties were studied with or without an inserted thin tantalum nitride (TaNx) layer. The gate electrode material influence on the dielectric properties was also investigated. Four types of gate materials, i.e., aluminum (Al), molybdenum (Mo), molybdenum nitride (MoN), and tungsten nitride (WN), were used in this study. The films were analyzed with ESCA, XRD, SIMS, and TEM. Films were made into MOS capacitors and characterized using I-V and C-V curves. Many promising results were obtained using this kind of high-k film. It is potentially applicable to future MOS devices.
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7

Han, Lei. "Investigation of Gate Dielectric Materials and Dielectric/Silicon Interfaces for Metal Oxide Semiconductor Devices." UKnowledge, 2015. http://uknowledge.uky.edu/ece_etds/69.

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The progress of the silicon-based complementary-metal-oxide-semiconductor (CMOS) technology is mainly contributed to the scaling of the individual component. After decades of development, the scaling trend is approaching to its limitation, and there is urgent needs for the innovations of the materials and structures of the MOS devices, in order to postpone the end of the scaling. Atomic layer deposition (ALD) provides precise control of the deposited thin film at the atomic scale, and has wide application not only in the MOS technology, but also in other nanostructures. In this dissertation, I study rapid thermal processing (RTP) treatment of thermally grown SiO2, ALD growth of SiO2, and ALD growth of high-k HfO2 dielectric materials for gate oxides of MOS devices. Using a lateral heating treatment of SiO2, the gate leakage current of SiO2 based MOS capacitors was reduced by 4 order of magnitude, and the underlying mechanism was studied. Ultrathin SiO2 films were grown by ALD, and the electrical properties of the films and the SiO2/Si interface were extensively studied. High quality HfO2 films were grown using ALD on a chemical oxide. The dependence of interfacial quality on the thickness of the chemical oxide was studied. Finally I studied growth of HfO2 on two innovative interfacial layers, an interfacial layer grown by in-situ ALD ozone/water cycle exposure and an interfacial layer of etched thermal and RTP SiO2. The effectiveness of growth of high-quality HfO2 using the two interfacial layers are comparable to that of the chemical oxide. The interfacial properties are studied in details using XPS and ellipsometry.
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8

Genevès, Thomas. "Elaboration et caractérisation de couches ultra-minces de silicate de baryum en tant qu'oxyde de grille alternatif." Phd thesis, Université de Bourgogne, 2008. http://tel.archives-ouvertes.fr/tel-00359449.

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La miniaturisation des dispositifs élémentaires de la technologie CMOS impose le remplacement de l'oxyde de silicium pour l'élaboration de l'oxyde de grille. Par l'identification des conditions de formation du silicate de baryum au contact direct du substrat de silicium, cette étude a révélé un candidat potentiel. En premier lieu, la réaction entre Ba et SiO2 aboutissant à la formation d'un silicate de baryum a été mise en évidence in-situ par XPS et SR-PES. Dans un second temps, des films de silicate de baryum ont été élaborés par co-déposition de baryum et d'oxygène à une température de 580 °C. Des traitements thermiques sous vide ont montré que le silicate de baryum est stable jusqu'à 900 °C. Des analyses ex-situ par SIMS et MET ont révélé une interface abrupte avec le substrat. Enfin, un dispositif dédié à la réalisation de croissances par MOCVD a été développé. Il a permis de montrer la possibilité de former un silicate de baryum. La réaction est favorisée lorsque le dépôt se déroule à température élevée, sous une pression partielle d'oxygène.
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9

Sun, Xiao. "Characterization and Fabrication of High k dielectric-High Mobility Channel Transistors." Thesis, Yale University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3578458.

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As the conventional scaling of Si-based MOSFETs would bring negligible or even negative merits for IC's beyond the 7-nm CMOS technology node, many perceive the use of high-mobility channels to be one of the most likely principle changes, in order to achieve higher performance and lower power. However, interface and oxide traps have become a major obstacle for high-mobility semiconductors (such as Ge, InGaAs, GaSb, GaN...) to replace Si CMOS technology.

In this thesis, the distinct properties of the traps in the high-k dielectric/high-mobility substrate system is discussed, as well as the challenges to characterize and passivate them. By modifying certain conventional gate admittance methods, both the fast and slow traps in Ge MOS gate stacks is investigated. In addition, a novel ac-transconductance method originated at Yale is introduced and demonstrated with several advanced transistors provided by collaborating groups, such as ultra-thin-body & box SO1 MOSFETs (CEA-LETI), InGaAs MOSFETs (IMEC, UT Austin, Purdue), and GaN MOS-HEMT (MIT).

By use of the aforementioned characterization techniques, several effective passivation techniques on high mobility substrates (Ge, InGaAs, GaSb, GeSn, etc.) are evaluated, including a novel Ba sub-monolayer passivation of Ge surface. The key factors that need to be considered in passivating high mobility substrates are revealed.

The techniques that we have established for characterizing traps in advanced field-effect transistors, as well as the knowledge gained about these traps by the use of these techniques, have been applied to the study of ionizing radiation effects in high-mobility-channel transistors, because it is very important to understand such effects as these devices are likely to be exposed to radiation-harsh environments, such as in outer space, nuclear plants, and during X-ray or UHV lithography. In this thesis, the total ionizing dose (TD) radiation effects of InGaAs-based MOSFETs and GaN-based MOS-HEMT are studied, and the results help to reveal the underlying mechanisms and inspire ideas for minimizing the TID radiation effects.

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10

Mutas, Sergej [Verfasser]. "Analysis of high-k materials with Local Electrode Atom Probe / Sergej Mutas." Aachen : Shaker, 2012. http://d-nb.info/1066198276/34.

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11

Lontsi, Fomena Mireille. "Etude théorique de la diffusion de l'oxygène dans des oxydes diélectriques‎$bRessource électronique." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2008. http://tel.archives-ouvertes.fr/tel-00402631.

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La miniaturisation des composants CMOS (Complementary Metal Oxide Semiconductor) impose l'emploi de matériaux diélectriques de permittivité élevée. LaAlO3 et SrTiO3 sont aujourd'hui parmi les meilleurs candidats ; toutefois, la diffusion de l'oxygène dans ces matériaux conduit à la dégradation des propriétés électriques et de l'interface avec le silicium. Ce travail théorique a pour but d'étudier les facteurs gouvernant, à l'échelle de la liaison chimique, la diffusion de l'ion oxygène. L'approche choisie repose sur la théorie de la fonctionnelle de la densité (DFT), couplée à des méthodes d'analyse de la densité électronique, et sur le développement d'un outil original : les cartes de densité d'énergie. Les régions de la densité électronique contribuant à la barrière de diffusion ont ainsi pu être identifiées; une optimisation de ces matériaux à l'échelle de la liaison chimique peut alors être envisagée.
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12

Kirsch, Paul Daniel. "Surface and interfacial chemistry of high-k dielectric and interconnect materials on silicon." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3034557.

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13

Mudanai, Sivakumar Panneerselvam. "Gate current modeling through high-k materials and compact modeling of gate capacitance." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3038191.

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14

Cheng, Cheng-Wei Ph D. Massachusetts Institute of Technology. "In-situ deposition of high-k dielectrics on III-V compound semiconductor in MOCVD system." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59216.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010.
Includes bibliographical references (p. 164-168).
In situ deposition of high-k materials to passivate the GaAs in metal organic chemical vapor deposition (MOCVD) system was well demonstrated. Both atomic layer deposition (ALD) and chemical vapor deposition (CVD) methods were applied in this research. The CVD aluminum nitride (AIN) was first selected to be in situ deposited on GaAs surface by using trimethlyaluminum(TMA) and dimethylhydrazine (DMHy). However, the frequency dispersion of Capacitance-Voltage (C-V) curves for in situ AIN/GaAs samples are always large because of the existence of high interfacial defect state density (Dit) due to the nitridization of the GaAs surface during the AIN deposition. In order to avoid the surface reaction, in situ ALD of aluminum oxide (A1₂O₃) on GaAs in MOCVD system was proposed. Isopropanol (IPA) was chosen as the oxygen source for A1₂O₃ ALD and the mechanism was investigated. Pure A120 3 thin film was obtained and no arsenic or gallium oxide was observed at the interface. Both frequency dispersion of C-V curve and the Di, of oxide/p-GaAs interface are low for this process. In situ CVD A1₂O₃ on GaAs was also performed. Gallium oxide (Ga₂O₃) was observed at the interface. The Ga₂O₃ was enriched in the A1₂O₃ above the interface during the deposition process and a possible mechanism was proposed. This layer reduces the frequency dispersion of the C-V characteristics and lowers the Dit of n-type GaAs sample. After the in situ method had been successfully established, ex situ experiments was also performed to compare the results with in situ process in the same MOCVD system. Annealing native oxide covered GaAs samples in Arsine (AsH 3) prior to ALD A1₂O₃ results in C-V characteristics of the treated samples that resemble the superior C-V characteristics of p-type GaAs. Besides, both TMA and IPA show self-cleaning effect on removing the native oxide in ex situ process. The discrepancy in the C-V characteristics was observed in in situ p- and n-type GaAs samples. Finally, the entire Dit energy distributions of interfaces from different processes were determined by conductance frequency method with temperature-variation C-V measurement. The existence of Ga₂O₃ at interface was found to be the possible source to lower the density of mid-gap defect state. From the C-V simulation, the mid-gap defect states are acceptor-like (Gallium Vacancies) and the source to cause high frequency dispersion of the C-V curves for n-type substrate. The relation between the interfacial defect state distribution and the processes was correlated.
by Cheng-Wei Cheng.
Ph.D.
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15

Li, Haoxiang. "Angle-Resolved Photoemission Spectroscopy Study of High Temperature Superconductor Cuprate, and Potential High Temperature Superconductors K-Doped p-Terphenyl and Trilayer Nickelate." Thesis, University of Colorado at Boulder, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10642070.

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The macroscopic quantum phenomenology of superconductivity has attracted broad interest from both scientific research and applications. Many exotic physics found in the first high $T_C$ superconductor family cuprate remain unsolved even after 30 years of intense study. Angle-Resolved Photoemission Spectroscopy (ARPES) provides the direct probe to the major information of the electronic interactions, which plays the key role in these exotic physics including high $T_C$ superconductivity. ARPES is also the best tool to study the electronic structure in materials that potentially hold high $T_C$ superconductivity, providing insight for materials research and design. In this thesis, we present the ARPES study of the cuprate high $T_C$ superconductor Pb doped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, and potential high $T_C$ superconductors K doped \textit{p}-terphenyl, and trilayer nickelate La$_4$Ni$_3$O$_{10}$. For Pb doped Bi2212, our study focuses on the key part of the electronic interactions---the self-energies. With the development of a novel 2-dimensional analysis technique, we present the first quantitative extraction of the fully causal complex self-energies. The extracted information reveals a conversion of the diffusive strange-metal correlations into a coherent highly renormalized state at low temperature followed by the enhancement of the number of states for pairing. We then further show how this can lead to a strong positive feedback effect that can stabilize and strengthen superconducting pairing. In K doped \textit{p}-terphenyl, we discover low energy spectral gaps that persist up to 120 K, consistent with potential Meissner effect signal from previous studies. Among a few potential origins for these gaps, we argue that the electron pairing scenario is most likely. For La$_4$Ni$_3$O$_{10}$, we present the Fermiology and electron dynamics of this material, and they show certain similarities to the cuprate electronic structure, as well as a few unique features.

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Gao, Yong. "Deposition, stabilization and characterization of zirconium oxide and hafnium oxide thin films for high k gate dielectrics." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/290136.

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As the MOS devices continue to scale down in feature size, the gate oxide thickness is approaching the nanometer node. High leakage current densities caused by tunneling is becoming a serious problem. Replacing silicon oxide with a high kappa material as the gate dielectrics is becoming very critical. In recent years, research has been focused on a few promising candidates, such as ZrO₂, HfO₂, Al₂O₃, Ta₂O₅, and some silicates. However, unary metal oxides tend to crystallize at relatively low temperatures (less than 700°C). Crystallized films usually have a very small grain size and high leakage current due to the grain boundaries. The alternatives are high κ oxides which are single crystal or amorphous. Silicates remain amorphous at high temperatures, but have some problems such as phase separation, interface reaction, and lower κ value. In this work, we addressed the crystallization problems of zirconium oxide and hafnium oxide thin films. Both of these two thin films were deposited by DC reactive magnetron sputtering so that very dense films were deposited with little damage. A specially designed system was set up in order to have good control of the deposition process. The crystallization behavior of as-deposited amorphous ZrO₂ and HfO₂ films was studied. It was found that the films tended to have higher crystallization temperature when the films were thinner than a critical thickness of approximately 5 nm. However, it was still well below 900°C. The crystallization temperature was significantly increased by sandwiching the high kappa oxide layer between two silica layers. Ultra thin HfO₂ films of 5nm thickness remained amorphous up to 900°C. This is the highest crystallization temperature which has been reported. The mechanisms for this effect are proposed. Electrical properties of these high kappa dielectric films were also studied. It was found that ultra thin amorphous HfO₂ and ZrO₂ films had superior electrical properties to crystalline films. The leakage current density of ultra thin amorphous films was at least two orders of magnitude lower than that of crystallized films. Amorphous films also showed much less hysteresis in the capacitance-voltage curve than uncapped crystallized films. The mechanisms for the electrical property differences between ultra thin crystalline and amorphous films were studied. Due to successful control of the low dielectric interfacial layer thickness, an effective oxide thickness of 1.2 and 1.4 nm was obtained for HfO₂ and ZrO₂ films, respectively.
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17

Reddy, Raj. "A study of high-K dielectric materials in conjunction with a multilayer thick-film system." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43280.

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A new family of dielectric materials has been studied, individually as thick-film capacitors and as buried components incorporated in second-order lowpass and bandpass RC active filter circuits. The materials were electrically characterized in terms of the variation of dielectric constant and dissipation factor with frequency. The performance of the filter circuit is related to the characteristics of the dielectric materials. An analysis of the circuit is developed which accounts for the capacitor losses.
Master of Science
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18

Vieluf, Maik. "Hochauflösende Rutherford-Streuspektrometrie zur Untersuchung von ZrO2-Schichtwachstum im Anfangsstadium." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-38113.

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Die vorliegende Arbeit entstand im Rahmen einer Kooperation des Forschungszentrums Dresden-Rossendorf mit Qimonda Dresden GmbH & Co. OHG. Mithilfe der hochauflösenden Rutherford-Streuspektrometrie (HR-RBS) wurden das Diffusionsverhalten und Schichtwachstum von ZrO2 auf SiO2 und TiN im Anfangsstadium untersucht. Auf Grund der exzellenten Tiefenauflösung von 0,3 nm an der Oberfläche stand die Analyse von Konzentrationsprofilen in ultradünnen Schichten, respektive an deren Grenzflächen im Vordergrund. Zur qualitativen Verbesserung der Messergebnisse wurde erstmals ein zweidimensionaler positionsempfindlicher Halbleiterdetektor in den Aufbau der HR-RBS implementiert und charakterisiert. Außerdem wurde ein Messverfahren in Betrieb genommen, das mögliche Schädigungen durch den Ioneneintrag in die Messprobe minimiert. Durch die Optimierung der experimentellen Bedingungen und die Entwicklung eines Programmpaketes zur Unterstützung des Analysten konnte ein effizienter Routine-Messablauf erstellt werden. Im Moment einer binären Kollision zwischen einfallendem Ion und Targetelement kommt es bei kleinem Stoßparameter zu Veränderungen des Ladungszustands der gestreuten Ionen, insbesondere durch die abrupte Geschwindigkeitsänderung des Projektils und der Überlappung der Elektronenwolken. Bei der HR-RBS mit Energie separierendem Dipolmagneten muss zur Interpretation von Streuspektren die Ladungszustandsverteilung der gestreuten Projektile bekannt sein. Erstmalig konnte eine signifikante Abhängigkeit der Ladungszustandsverteilung gestreuter C-Ionen sowohl von der Schichtdicke als auch der Ordnungszahl des detektierten Targetelements, hier der vierten Nebengruppe, nachgewiesen werden. Diese gewonnen Erkenntnisse ermöglichten systematische Untersuchungen zum ZrO2-Schichtwachstum im Anfangsstadium. Zur Herstellung der ZrO2-Schichten wurde die Atomlagenabscheidung (ALD) verwendet. Anhand der nachgewiesenen Agglomeration von ZrO2 auf nativen SiO2 wurde mithilfe der Rasterkraftmikroskopie (AFM) zur Bestimmung von Oberflächenrauigkeiten eine Methode konzipiert, welche die Auswirkung lokaler Schichtdickeninhomogenitäten auf die niederenergetische Flanke eines Streuspektrums berücksichtigt. Auf dieser Grundlage durchgeführte Simulationsrechnungen ergeben, dass keine Diffusion von Zr in die darunter liegende Schicht stattfand, jedoch eine ZrSiO4-Grenzflächenschicht existiert. Für das Wachstum von ZrO2 auf TiN wird aus den hoch aufgelösten Streuspektren ein völlig anderes Verhalten abgeleitet. Messungen zu Oberflächentopografien der TiN-Schicht liefern nicht zu vernachlässigende Werte für die Rauigkeit. Um den Einfluss der Oberflächenrauigkeit auf die Form des hoch aufgelösten Spektrums erfassen zu können, wurde eine Software entwickelt. Auf Basis von AFM-Messungen ermöglicht dieses Programm das Extrahieren einer Energieverteilung aus den Weglängen von ausschließlich an der Oberfläche gestreuten Ionen. Unter Berücksichtigung des Effekts der Oberflächenrauigkeit auf die HR-RBS Spektrenform konnte die Diffusion von Zr in das polykristalline TiN erstmals verifiziert werden. Die Beobachtungen weisen daraufhin, dass bereits nach dem ersten ALD-Zyklus ein geringer Anteil der deponierten Zr-Atome bis in eine Tiefe von etwa 3 nm in das TiN diffundiert. Die vorläufigen Ergebnisse legen Korngrenzendiffusion nahe
This thesis originated from a cooperation between Research Center Dresden-Rossendorf and Qimonda Dresden GmbH & Co. OHG. By means of High Resolution Rutherford Backscattering Spectrometry (HR-RBS) the diffusion behaviour and layer growth of ZrO2 on SiO2 and TiN in the initial regime were investigated. The analysis of concentration profiles in ultrathin layers and interfaces was the focus of this work, made possible by the excellent depth resolution of less than 0.3 nm near the surface. For the first time a two-dimensional position sensitive semiconductor detector was implemented and characterized in the setup of the HR-RBS for the improvement of the quality of the measurement results. Furthermore, a measurement procedure was put into operation that allowed the reduction of ion induced damage. Through the optimization of the experimental conditions and the development of a program package for the support of the analyst, an efficient measurement procedure could be routinely ensured. At the time of a binary collision between the incident ion and the target element with a small impact factor, the charge state changes frequently, especially due to the abruptly decreasing ion velocity of the projectile and the overlapping of the electron clouds. For HR-RBS with an energy-separating dipole magnet, the charge state distribution of the scattered ions must be known for the interpretation of the measured spectra. For the first time a significant dependence of the charge state distribution of the scattered C ions on the layer thickness as well as atomic number of the detected target elements, here from the fourth subgroup, was emonstrated. This new knowledge allowed systematic investigations of the ZrO2 layer growth in the initial regime. The ZrO2 layers were produced by means of the atomic layer deposition (ALD). Based on the evidence for agglomeration of ZrO2 on SiO2 a method was introduced, which takes local thickness variations into account during the simulation of the HR-RBS spectra. An accurate statement about the ZrO2/SiO2 interface was possible due to the extraction of the thickness variation by the atomic force microscopy (AFM). The boundary surface is sharp except for a small intermediate ZrSiO4 layer and no diffusion of Zr atoms in SiO2 could be detected. A quite different behaviour could be derived from high resolution spectra for the growth of ZrO2 on TiN. Measurements of the surface topography of the TiN layer revealed non negligible values for the surface roughness. A program was developed to capture the influence of the surface roughness on the shape of the high resolution spectrum. This software uses AFM measurements to extract an energy distribution from calculated path length differences for ions scattered at the sample surface. Diffusion of Zr into polycrystalline TiN was demonstrated for the first time taking into account the effect of the surface roughness on the shape of the spectra. This observation indicates that already after the first ALD reaction cycle a small part of the deposited Zr atoms diffuses into the TiN layer up to a depth of 3 nm. Such preliminary results suggest grain boundary diffusion
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19

Sreenivasan, Raghavasimhan. "Metal-gate/high-k dielectric stack engineering by atomic layer deposition : materials issues and electrical properties /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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20

Guiraud, Alexandre. "Intégration de matériaux à forte permittivité diélectrique dans les mémoires non volatile avancées." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4763/document.

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Ce travail de thèse porte sur l'intégration de matériaux de haute constante diélectrique (High-k) en tant que diélectrique interpoly dans les mémoires non volatiles de type Flash. L'objectif est de déterminer quel matériaux High-k seraient des candidats probables au remplacement de l'empilement ONO utilisé en tant que diélectrique interpoly. Une gamme de matériaux high-k ont été étudiés via des caractérisations électriques (I-V, C-V, statistique de claquage…) et physiques (TEM, EDX, XPS…) afin d'éliminer les matériaux ne répondant pas au cahier des charges d'un diélectrique interpoly. Les difficultés et les obstacles liés a l'intégration de matériaux High-k dans une chaine de procédés de fabrication de mémoires Flash ont été pris en compte, et des solutions ont été proposées
The work of this thesis is on integration of high dielectric constant materials (High-k) as dielectric interpoly in Flash non volatile memories. The objective is to determine which High-k materials are suitable as interpoly dielectric in place of the ONO stack currently used. A range of High-k materials have been studied by electrical characterizations (I-V, C-V, breakdown statistics…) and physical characterizations (TEM, EDX, XPS…) in order to select those with the best properties for an interpoly dielectric. The difficulties in integration of High-k materials in a Flash memory process flow have been taken in account and solutions have been proposed
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21

Tse, Koon-Yiu. "High-K gate oxides and metal gate materials for future complementary metal-oxide-semiconductor field-effect transistors." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611979.

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22

Xia, Zhanbo. "Materials and Device Engineering for High Performance β-Ga2O3-based Electronics." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587688595358557.

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23

Niu, Gang. "Epitaxy of crystalline oxides for functional materials integration on silicon." Phd thesis, Ecole Centrale de Lyon, 2010. http://tel.archives-ouvertes.fr/tel-00601689.

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Oxides form a class of material which covers almost all the spectra of functionalities : dielectricity, semiconductivity, metallicity superconductivity, non-linear optics, acoustics, piezoelectricity, ferroelectricity, ferromagnetism...In this thesis, crystalline oxides have beenintegrated on the workhorse of the semiconductor industry, the silicon, by Molecular Beam Epitaxy (MBE).The first great interest of the epitaxial growth of crystalline oxides on silicon consists in the application of "high-k" dielectric for future sub-22nm CMOS technology. Gadoliniumoxide was explored in detail as a promising candidate of the alternative of SiO2. The pseudomorphic epitaxial growth of Gd2O3 on Si (111) was realized by identifying the optimal growth conditions. The Gd2O3 films show good dielectric properties and particularly an EOTof 0.73nm with a leakage current consistent with the requirements of ITRS for the sub-22nmnodes. In addition, the dielectric behavior of Gd2O3 thin films was further improved by performing PDA treatments. The second research interest on crystalline oxide/Si platform results from its potential application for the "More than Moore" and "Heterogeneous integration" technologies. TheSrTiO3/Si (001) was intensively studied as a paradigm of the integration of oxides on semiconductors. The crystallinity, interface and surface qualities and relaxation process of the STO films on silicon grown at the optimal conditions were investigated and analyzed. Several optimized growth processes were carried out and compared. Finally a "substrate-like" STO thin film was obtained on the silicon substrate with good crystallinity and atomic flat surface. Based on the Gd2O3/Si and SrTiO3/Si templates, diverse functionalities were integrated on the silicon substrate, such as ferro-(piezo-)electricity (BaTiO3, PZT and PMN-PT),ferromagnetism (LSMO) and optoelectronics (Ge). These functional materials epitaxially grown on Si can be widely used for storage memories, lasers and solar cells, etc.
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24

CARUSO, FRANCESCO. "Study of electrical conduction and defects in high-permittivity metal oxides: experiments and simulation." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/382298.

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Inizialmente studiati dall’industria elettronica per sostituire lo strato isolante di SiO2, gli ossidi metallici sono ora ampiamente utilizzati come strati attivi o isolanti in una moltitudine di dispositivi elettronici. Le proprietà elettriche sono fortemente correlate ai difetti atomici, che generano stati elettronici localizzati all'interno del band gap che fungono da trappole di carica. La comprensione dei meccanismi fisici e del ruolo dei difetti che regolano il trasporto di carica negli ossidi metallici è pertanto della massima importanza per l'ottimizzazione dei dispositivi nanoelettronici. Tuttavia, il trasporto di carica e il ruolo dei difetti negli ossidi metallici è ancora oggetto di dibattito e non è stata raggiunta una comprensione completa e autoconsistente in ampi regimi di spessore, temperatura e tensione. In questa tesi ho studiato i meccanismi di conduzione in condensatori metallo-isolante-metallo (MIM) che incorporano tre materiali modello Al2O3, HfO2 e HfO2 drogato con Al (AlHfO) depositati mediante deposizione di strati atomici (ALD), in tre diversi spessori 5, 10 e 20nm. Inoltre, sono stati analizzati gli ossidi a base di Hf depositati utilizzando acqua o ozono come fonte di ossigeno ALD, nonché AlHfO a due concentrazioni di Al (5% e 17%). Lo scopo di questo studio è identificare le proprietà delle trappole di carica di ciascun materiale e studiare il percorso che gli elettroni percorrono all'interno dei dielettrici di ossidi metallici sotto l’azione del campo elettrico applicato. Viene inoltre discusso l'impatto dei diversi processi di produzione e dello spessore dei film sulle proprietà del materiale. Le proprietà delle trappole sono estratte dalla caratteristica sperimentale corrente-tensione dei condensatori MIM, in un ampio regime di temperatura e tensione, utilizzando un modello di trasporto di carica completo implementato nel software di simulazione Ginestra (Applied Materials). I difetti del Al2O3 sono caratterizzati da un'energia di ionizzazione termica ET~3.5eV e da un'energia di rilassamento EREL~1eV, in accordo con i calcoli ab-initio per le vacanze di ossigeno riportati in letteratura. In ogni ossido spesso 10 e 20nm a base di Hf sono identificati due tipi di difetti, caratterizzati da ET~1.8eV per le trappole "superficiali" e ET~3eV per le trappole "profonde". L'uso dell'acqua durante la deposizione ALD introduce cariche positive fisse nell'ossido. L'introduzione di atomi di Al nel HfO2 aumenta il band gap dell'ossido, senza influire sulla densità e sulle proprietà dei difetti. L'analisi ha permesso di identificare la posizione delle trappole maggiormente coinvolte nella conduzione e il meccanismo di trasporto dominante in ossidi spessi 20nm, ad ogni campo elettrico applicato. Nonostante le diverse proprietà, in ciascun materiale si verificano correnti di spostamento transitorie a bassi campi elettrici, originate dall'intrappolamento e dall'emissione di elettroni in/da trappole vicine all'interfaccia metallo/ossido. Il trasporto di elettroni attraverso l'ossido avviene solo a campi elettrici più elevati, in due modi diversi. Se una grande densità di trappole è localizzata energeticamente vicino al livello di Fermi degli elettrodi (come nel caso del HfO2), gli elettroni passano da una trappola all'altra fino a raggiungere l'anodo. Altrimenti, quando le trappole sono più vicine alla banda di conduzione (come nel Al2O3 e AlHfO), gli elettroni passano dal catodo in una trappola e poi nella banda di conduzione dell'ossido, interagendo solo con trappole vicino al catodo. Questi risultati potrebbero avere profonde implicazioni per l'ottimizzazione dei futuri dispositivi nanoelettronici. Inoltre, poiché negli ossidi metallici l'intrappolamento, la generazione di difetti e i processi di rottura sono fortemente correlati, i risultati presentati possono fornire nuove indicazioni sul processo di rottura degli ossidi metallici, con un impatto sull'affidabilità dei dispositivi.
Originally investigated in the electronic manufacturing to replace the SiO2 insulating layer, metal oxides are now extensively used as insulating or active layers in a multitude of electronics devices. It is known that the electrical properties are strongly correlated to atomic defects, which generate localized electronic states inside the band gap that act as charge traps. Therefore, the understanding of the physical mechanisms and the role of defects governing the charge transport in metal oxide stacks is of utmost importance for the optimization of nano-electronic devices. However, the charge transport and role of defects in metal oxides is still under debate and a complete and self-consistent understanding over large thickness, temperature and voltage regimes is not reached. In this thesis I investigated the conduction mechanisms in metal-insulator-metal (MIM) capacitors incorporating three model materials Al2O3, HfO2 and Al-doped-HfO2 (AlHfO) deposited by atomic layer deposition (ALD), in three different thicknesses 5, 10, and 20 nm. Furthermore, Hf-based oxides deposited using either water or ozone as ALD oxygen source, as well as AlHfO at two Al concentrations (5% and 17%) were analyzed. The aim of this study is to identify the charge traps properties of each material and investigate the path that electrons take within metal oxide dielectrics under applied electric field. Moreover, the impact of different manufacturing processes and film thicknesses on the material properties is discussed. Traps properties are extracted from experimental current-voltage characteristics of MIM capacitors, over a broad temperature and voltage regime, using a comprehensive charge transport model implemented in the Ginestra® (Applied Materials, Inc.) simulation software. Defects in Al2O3 are characterized by a thermal ionization energy ET≈3.5 eV below the dielectric conduction band minimum (CBM) and a relaxation energy EREL≈1 eV, in agreement with the ab-initio calculations of oxygen vacancies reported in literature. Two kinds of defects are identified in each 10 and 20 nm-thick Hf-based oxide, characterized by ET≈1.8eV for "shallow" traps, and ET≈3eV for "deep" traps. The use of water as oxygen source during the oxide ALD introduces fixed positive charges in the oxide. The introduction of Al atoms in HfO2 increases the oxide energy band gap, without significantly impacting on the density and properties of defects. The analysis allowed to identify the location of traps most involved in the conduction and the dominant transport mechanism in 20 nm-thick oxides, at each applied electric field. Despite the different properties, in each material transient displacement currents occur at low electric fields, originating from electron trapping and emission at traps near the metal/oxide interface. The transport of electrons through the oxide occurs only at higher electric fields, in two different ways. If a large density of traps is energetically located near the electrodes Fermi level (as in HfO2), the electrons tunnel from trap to trap until they reach the anode. Otherwise, when traps are closer to the conduction band (as in Al2O3 and AlHfO), the electrons tunnel from the cathode into one trap and then into the oxide conduction band, interacting only with traps near the cathode. These findings may have profound implications for the functional optimization of future nano-electronics devices. Furthermore, since in metal oxides trapping, defects generation and breakdown processes are strongly related, results can provide new insight in the breakdown process of metal oxides, impacting on device reliability.
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25

Baristiran, Kaynak Canan [Verfasser], and Bernd [Akademischer Betreuer] Tillack. "Characterization of Perovskite-like High k Dielectric Materials for Metal-Insulator-Metal Capacitors / Canan Baristiran Kaynak. Betreuer: Bernd Tillack." Berlin : Universitätsbibliothek der Technischen Universität Berlin, 2013. http://d-nb.info/1031280227/34.

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26

Wu, Dongping. "Novel concepts for advanced CMOS : Materials, process and device architecture." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3805.

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The continuous and aggressive dimensional miniaturization ofthe conventional complementary-metal-oxide semiconductor (CMOS)architecture has been the main impetus for the vast growth ofIC industry over the past decades. As the CMOS downscalingapproaches the fundamental limits, unconventional materials andnovel device architectures are required in order to guaranteethe ultimate scaling in device dimensions and maintain theperformance gain expected from the scaling. This thesisinvestigates both unconventional materials for the gate stackand the channel and a novel notched-gate device architecture,with the emphasis on the challenging issues in processintegration.

High-κ gate dielectrics will become indispensable forCMOS technology beyond the 65-nm technology node in order toachieve a small equivalent oxide thickness (EOT) whilemaintaining a low gate leakage current. HfO2and Al2O3as well as their mixtures are investigated assubstitutes for the traditionally used SiO2in our MOS transistors. These high-κ filmsare deposited by means of atomic layer deposition (ALD) for anexcellent control of film composition, thickness, uniformityand conformality. Surface treatments prior to ALD are found tohave a crucial influence on the growth of the high-κdielectrics and the performance of the resultant transistors.Alternative gate materials such as TiN and poly-SiGe are alsostudied. The challenging issues encountered in processintegration of the TiN or poly-SiGe with the high-k are furtherelaborated. Transistors with TiN or poly-SiGe/high-k gate stackare successfully fabricated and characterized. Furthermore,proof-of-concept strained-SiGe surface-channel pMOSFETs withALD high-κ dielectrics are demonstrated. The pMOSFETs witha strained SiGe channel exhibit a higher hole mobility than theuniversal hole mobility in Si. A new procedure for extractionof carrier mobility in the presence of a high density ofinterface states found in MOSFETs with high-κ dielectricsis developed.

A notched-gate architecture aiming at reducing the parasiticcapacitance of a MOSFET is studied. The notched gate is usuallyreferred to as a local thickness increase of the gatedielectric at the feet of the gate above the source/drainextensions. Two-dimensional simulations are carried out toinvestigate the influence of the notched gate on the static anddynamic characteristics of MOSFETs. MOSFETs with optimizednotch profile exhibit a substantial enhancement in the dynamiccharacteristics with a negligible effect on the staticcharacteristics. Notched-gate MOSFETs are also experimentallyimplemented with the integration of a high-κ gatedielectric and a poly-SiGe/TiN bi-layer gate electrode.

Key words:CMOS technology, MOSFET, high-κ, gatedielectric, ALD, surface pre-treatment, metal gate, poly-SiGe,strained SiGe, surface-channel, buried-channel, notchedgate.

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27

Uppal, Hasan Javed. "Nanoscale performance, degradation and defect analysis of mos devices using high-k dielectric materials as gate stacks by atomic force microscopy." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509394.

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28

Tao, Liang. "Atomic-scale calculations of interfacial structures and their properties in electronic materials." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1127163029.

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29

Wang, J. B., and 王俊彬. "The Study of High-K material La2O3." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/75206457477114214117.

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碩士
國立交通大學
電子工程系
88
In recent years, there are large amounts of research and development of high K material for the reason of the scaling down and burst improvement of memory technology. The high K technology has reached a colossal success, just like BaSrTiO3 (BST, K=200), Ta2O5 (K=30~75), etc. But, there are several kind weaknesses of these developed high-K materials. One of them is the interfacial diffusion between the interface of the high K material and Si. For eliminating this effect, high K La2O3 gate dielectrics has been developed by using a process of direct thermal oxidization of deposited La. Using this high K material as the gate dielectric, MOSFETs and MOS capacitors have been fabricated. From the measurement of capacitance, the 33Å La2O3 has a K value of 27 that has an equivalent oxide thickness of 4.8 Å when considering the quantum correction. This high K is further evidenced from MOSFETs’ high current drive and high charge-to-breakdown comparable with SiO2 are obtained that demonstrates excellent reliability. Good dielectric integrity is evidenced from the low leakage current density of 0.06A/cm2 at -1V, high effective breakdown field of 13.5 MV/cm, low interface density of 3x1010ev-1cm-2. The achieved low equivalent oxide thickness is due to the high thermodynamic stability on Si and also stable for hydrogen annealing up to 550ºC.
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30

陳彥廷. "The Integrated Investigation of High-k Material Al2O3." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/21493788954482447540.

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31

Lu, C. H., and 呂承翰. "High-K material Al2O3 thin films as device insulators." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/29648442156745189807.

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碩士
國立交通大學
電子工程系
87
The scaling limit for gate oxide in VLSI is determined by the direct tunneling leakage current. Further device performance improvement can be obtained using a higher dielectric constant material. We have studied the aluminum oxide (Al2O3) as an alternative gate dielectric. In this thesis we report a very simple process to fabricate aluminum oxide (Al2O3) gate dielectric with K (~8 to 9.8) greater than the K of Si3N4. Aluminum oxide (Al2O3) is formed by directed oxidation from thermally evaporated Al. The 4.8nm aluminum oxide (Al2O3) has ~7 orders lower leakage current than equivalent 2.1nm SiO2. Good aluminum oxide (Al2O3)/ Si interface was evidenced by the low interface density of 5*1011 /cm2-ev and compatiable electron effective mobility with thermal SiO2. Good reliability is measured from the small SILC after constant current and constant voltage stress.
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32

Yu, Chia-Chen, and 尤嘉正. "Simulation of MOSFET and Flash devices with High-K Material." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/79612221877414131488.

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33

Shie, Wen-Bin, and 謝文斌. "The Interface Investigation of High-K Material Al2O3 on Si Substrate." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/rj66zh.

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碩士
國立交通大學
電子工程系所
92
Aluminum oxide (Al2O3) is one of the potential high-k materials. It has the higher dielectric constant (8~10), higher barrier height ( 2.9eV for electrons , and 4.3eV for holes ), and excellent thermal stability. In the thesis, physical, electrical and reliability characteristics of Al2O3 film with NH3 surface treatment and Post Deposition Annealing (PDA) in the O2 and N2 ambient were studied. The PDA can effectively reduce surface roughness. The PDA and NH3 surface treatments both can improve the C-V curves. Moreover, the lower leakage current is observed in NH3 surface treatment samples. The reliabilities can be improved by the NH3 surface treatment after PDA in a N2 ambient. The conduction mechanism in the Al2O3 thin film is dominated by the Schottky emission. To sum up, the characteristics of Al2O3 gate dielectrics with NH3 surface treatment and subsequent PDA treatment described above are effectively improved. This novel NH3 and PDA treatment provides an alternative for post metal-oxide deposition treatment in nanoscale device application.
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34

Hsu, Shiou-Hau, and 許修豪. "Investigation of High-K Material HfO2 on Metal-Insulator-Metal Capacitor." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/04957264503747184756.

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碩士
國立交通大學
電子工程系所
94
Abstract Continuous down-scaling of the size of metal–insulator–metal (MIM) capacitors is required to reduce chip size and the cost of analog and RF ICs. The use of a high-k dielectric is the only way to achieve this goal, since decreasing the dielectric thickness to achieve high capacitance density degrades the leakage current. Metal-insulator- metal (MIM) capacitors are fabricated using sputtered HfO2 with Ta for top and bottom electrodes. A very high density of 25.67fF/um2 has been measured in metal–insulator–metal (MIM) capacitors which use high-k HfO2 the dielectric. The characteristics the MIM capacitors show the leakage current densities around 3.5×10-7 A/ cm2
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35

Chen, Chi-Lin, and 陳麒麟. "Preparation of high–k material hafnium silicate by sol-gel method." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/43499511255535387204.

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碩士
國立高雄大學
應用化學系碩士班
96
In present study, the hafnium oxide and hafnium silicate films with different silicon/hafnium ratios were prepared on silicon substrate by sol-gel method. The thin films were high temperature annealed by furnace annealing or rapid thermal annealing (RTA). In order to investigate the thickness effects of hafnium oxide and hafnium silicate, one to five layers of thin films were deposited by repetitive spin-on process. Then, a Metal-Insulator-Semiconductor (MIS) structure was constructed for electrical properties analysis. The experiment results showed that both the one layer thickness and crystallization temperature of film increased with the ratios of silicon/hafnium, regardless of annealing conditions. The binding energy of film surface was studied by X-ray photoelectron spectroscopy (XPS) analyses and indicated that the signal position of Hf4f, Si2p and O1s shifted to a higher binding energy by increasing the silicon/hafnium ratio or the annealing temperature. Otherwise, the XPS results of the hafnium silicate thin films, after annealed by RTA, suggested a possible occurrence of phase separation. For electrical property measurement, upper electrode was deposited on top of high-k film and then post-annealed to improve the electrode/film interface properties. We found that post-annealing reduced the leakage current of films to be 10-8~10-9 A/cm and also suppressed their flat band voltage shift. In conclusion, most properties of the thin films were observed to be better by RTA process than by furnace process.
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36

Chen, Shih-Chang, and 陳世璋. "The Interface Investigation of High-K Material HfO2 on Si Substrate." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/15185369275557096826.

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碩士
國立交通大學
電子工程系
91
According to the scalling rules, aggressive scaling has led to silicon dioxide (SiO2) gate dielectrics as ultra thin in state-of-the-art CMOS technologies. As a consequence, static leakage power due to direct tunneling through the gate oxide has been increasing at an exponential rate. As technology roadmaps call for sub-10Å gate oxides within the next five years, a variety of alternative high-k materials are being investigated as possible replacements for SiO2. The higher dielectric constants in these materials allow the use of physically thicker films, potentially reducing the tunneling current while maintaining the gate capacitance needed for scaled device operation. Hafnium oxide ( HfO2 ) is the most potential high-k material. It has the higher dielectric constant , higher barrier height ( 1.6eV for electrons , and 3.4eV for holes ), and excellent stability. In our experiments, the variation of leakage current , hump in C-V curves, interfacial layer increasing, and electron trapping are observed and investigated in un-surface treatment HfO2 samples. The rapid thermal oxide ( RTO ) and NH3 surface treatments both can improve the C-V curves. Moreover, the lower leakage current is observed in NH3 surface treatment samples. The results of stress induces leakage current ( SILC ) measurements show the severe electron trapping under the high electric field stress. The reliabilities can be improved by the RTO surface treatment, and the dielectric breakdown much depends on the quality of the interfacial layer. The conduction mechanism in the HfO2 thin film is dominated by the Frenkel-Poole emission.
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37

Zhao, Han 1982. "A study of electrical and material characteristics of III-V MOSFETs and TFETs with high-[kappa] gate dielectrics." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-12-2184.

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The performance and power scaling of metal-oxide-semiconductor field-effect-transistors (MOSFETs) has been historically achieved through shrinking the gate length of transistors for over three decades. As Si complementary metal-oxide-semiconductor (CMOS) scaling is approaching the physical and optical limits, the emerging technology involves new materials for the gate dielectrics and the channels as well as innovative structures. III-V materials have much higher electron mobility compared to Si, which can potentially provide better device performance. Hence, there have been tremendous research activities to explore the prospects of III-V materials for CMOS applications. Nevertheless, the key challenges for III-V MOSFETs with high-[kappa] oxides such as the lack of high quality, thermodynamically stable insulators that passivate the gate oxide/III-V interface still hinder the development of III-V MOS devices. The main focus of this dissertation is to develop the proper processes and structures for III-V MOS devices that result in good interface quality and high device performance. Firstly, fabrication processes and device structures of surface channel MOSFETs were investigated. The interface quality of In[subscript 0.53]Ga[subscript 0.47]As MOS devices was improved by developing the gate-last process with more than five times lower interface trap density (D[subscript it]) compared to the ones with the gate-first process. Furthermore, the optimum substrate structure was identified for inversion-type In[subscript 0.53]Ga[subscript 0.47]As MOSFETs by investigating the effects of channel doping concentration and thickness on device performance. With the proper process and channel structures, the first inversion-type enhancement-mode In[subscript 0.53]Ga[subscript 0.47]As MOSFETs with equivalent oxide thickness (EOT) of ~10 Å using atomic layer deposited (ALD) HfO₂ gate dielectric were demonstrated. The second part of the study focuses on buried channel InGaAs MOSFETs. Buried channel InGaAs MOSFETs were fabricated to improve the channel mobility using various barriers schemes such as single InP barrier with different thicknesses and InP/InAlAs double-barrier. The impacts of different high-[kappa] dielectrics were also evaluated. It has been found that the key factors enabling mobility improvement at both peak and high-field mobility in In[subscript 0.7]Ga[subscript 0.3]As quantum-well MOSFETs with InP/InAlAs barrier-layers are 1) the epitaxial InP/InAlAs double-barrier confining carriers in the quantum-well channel and 2) good InP/Al₂O₃/HfO₂ interface with small EOT. Record high channel mobility was achieved and subthreshold swing (SS) was greatly improved. Finally, InGaAs tunneling field-effect-transistors (TFETs), which are considered as the next-generation green transistors with ultra-low power consumption, were demonstrated with more than two times higher on-current while maintaining much smaller SS compared to the reported results. The improvements are believed to be due to using the In[subscript 0.7]Ga[subscript 0.3]As tunneling junction with a smaller bandgap and ALD HfO₂ gate dielectric with a smaller EOT.
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38

YU, SHENG-WANG, and 余聲旺. "Property of high k ceramic material and fabrication of trick film capacitor." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/15639755702394732797.

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39

Chou, Tung-huan, and 周棟煥. "Low Temperature Polycrystalline Silicon Thin-Film Flash Memory with High-k Material." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/81042257150324009588.

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碩士
國立交通大學
電子物理系所
94
In this thesis, we proposed the fabrication of low temperature polycrystallize silicon thin film with nonvolatile flash memory as named the SONOS-type poly-Si-TFT memories. In addition, the different high-k materials of trapping layer were used in this experiment, including the HfO2, Hf-silicate and Zr-silicate. We also analyze the electrical properties and the reliability of the SONOS-type poly-Si-TFT memories. It was demonstrated that the fabricated memories exhibit good performance. First, the large memory window was shown in the device with three different trapping layers. Second, these samples would have the high program/erase speed (1ms/10ms). Third, all the three samples can be operated up to 108 s with only 30% charge loss for the data retention performance under room temperature operation. However, the data retention for the sample with Hf-silicate trapping layer can be operated up to 108 s with only 10% charge loss. Fourth, our devices also have long retention time (>106s for 20% charge loss) and negligible read/write disturbances. Fifth, the 2-bit operation has been successfully demonstrated in these devices with different trapping layers. We also discuss the electrical characteristics of SONOS-type poly-Si-TFT memories with different tunneling oxide thickness. The device with thicker tunneling oxide thickness would have better data retention performance than the sample with thinner tunneling oxide thickness. In addition, our device with thicker tunneling oxide thickness would have good program/erase speed as well as the device with thinner tunneling oxide thickness. However the gate and drain disturbance are still problems in low temperature poly-crystallize silicon thin film flash memories. After NH3 plasma treatment, the performances of data retention and disturbance would be improved for our SONOS-type poly-Si-TFT memories. This is because the hydrogen atoms of NH3 can terminate dangling bonds and replace the weak bonds in the grain boundaries and SiO2/poly-Si interface and thus reduce the trap states in the poly-Si channel. Thus, both the performance and reliability of poly-Si TFTs were also improved. As long as the drain and gate disturbance can be reduced, this TFT flash memories are very promising for the future flash memory application.
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40

Huang, Ching-Chien, and 黃靖謙. "The Investigation of Metal-Insulator-Metal Capacitor Applying High-k Dielectrics Material." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/66095805506307248591.

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博士
國立交通大學
電子工程系所
97
According to International Technology Roadmap for Semiconductor (ITRS), continuous increasing the capacitance density is required to scale down the device size and the cost of Metal-Insulator-Metal (MIM) capacitors which are widely for Analog, RF and DRAM functions. However, they often occupy a large fraction of circuit area. To meet these requirements, high dielectric constant (k) materials provide the only solution since decreasing the dielectric thickness (tk) degrades both the leakage current and ΔC/C performance. To achieve this goal, the only choice is to increase the k value of the dielectrics, which have evolved from SiON (k~4-7), Al2O3 (k=10), HfO2 (k~22), Ta2O5 (k~25) to Nb2O5 (k~40). To further achieve the properties of MIM such as low leakage current, low voltage coefficient of capacitance and low temperature coefficient of capacitance. Thus, we have developed novel process and high-k dielectric materials, such as TiNiO (k~30-40), TiPO (k~26-32) and SrTiO3 (k>50) to achieve this technology. To further improve the small bandgap (EG) of these dielectrics, we apply the higher work-function Pt (5.7 eV) and Ir (5.3 eV) top electrode are used to give better device performance. Although SrTiO3 has large dielectric (k~50-200), the small conduction band offset (ΔEc) and bandgap leading to larger leakage current is a larger drawback. Besides, SrTiO3 shows its higher k values by forming nano-crystals, which is only practicable at a higher process temperature > 450oC. Furthermore, the high voltage coefficient of capacitance of SrTiO3 is also an important issue. Because Ta2O5 has very low voltage coefficient of capacitance and can considerably suppressed the leakage current, the overall electrical characteristics of MIM device could be improved by doping Ta2O5 into SrTiO3 MIM capacitor. Otherwise, we have developed a plasma treatment on dielectric to repair the defect of the dielectric to improve leakage current, voltage coefficient of capacitance and temperature coefficient of capacitance at the same time. Therefore, not only high capacitance and low leakage current, but also small voltage/temperature dependence of capacitance are obtained under limited thermal budget for back-end-integration. In addition to the measurement of capacitance at low frequency and the leakage current, the measurement of the S-parameters to investigated the characteristics of the MIM capacitors at RF regime are also demonstrated. By using the simulation software, the capacitance density of MIM capacitors at different frequencies was extracted. Besides, the related factors such as understandings of the mechanism of conductivity, the voltage/temperature dependence of capacitances, barrier height, and interfacial layer were investigated, and these are also useful in the development of advanced MIM capacitors.
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41

Lin, Ching-Lian, and 林慶廉. "Surface passivation of c-Si and HIT solar cells with high-k material." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/95779232098036805251.

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碩士
國立清華大學
電子工程研究所
102
Over 85% of the solar cells currently produced are based on crystalline silicon wafers. The efficiency of silicon solar cells is significantly affected by electronic recombination losses at the wafer surfaces. A surface passivation layer can be used to reduce electronic recombination losses. In this study, we used Atomic Layer chemical Deposition (ALD) to deposit high-k material as a passivation layer. At first we deposited different high-k materials on c-Si solar cells. We tried different passivation conditions, such as without high-k passivation, with Al2O3 in the front side, with Al2O3 on both sides, and with HfO2 on both sides. The result showed that cell with HfO2 on both sides achieved the highest efficiency of 15.542%. We also deposited HfO2 on HIT solar cells as surface passivation layer. Different passivation conditions such as without HfO2 passivation, with HfO2 on IP side, with HfO2 on IN side, and with HfO2 on both sides are used. HIT solar cell having passivation with HfO2 (8Å) on both sides achieved the highest efficiency. The highest efficiency obtained for HIT cell with HfO2 passivation was 11.68%, with a Voc of 0.61 V, Jsc of 31.276 mA/cm2 and FF of 0.612.
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42

Huang, Jheng-Yu, and 黃證宇. "The Effect of Ternary Material (Zr, Y, and O) High-k Gate Dielectrics." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/27598816189012526266.

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碩士
國立臺灣師範大學
機電科技研究所
100
In this study, zirconium (Zr) was doped into the Y2O3 layer through co-sputtering before rapid thermal annealing (RTA) at 550 ℃, 700 ℃, and 850 ℃and Al electrode formation. Two structures were formed: Al/ZrN/Y2O3/Y2O3+Zr/p-Si and Al/ZrN/Y2O3+Zr/Y2O3/p-Si. When Zr was doped on the upper layer, the crystallization was more significant than when Zr was doped on the bottom layer, as shown in the X-ray diffraction (XRD) diagram. This result showed that Zr can suppress oxygen diffusion. Additionally, the atomic force microscopy (AFM) data also showed that the surface roughness was worse when Zr was doped on the upper layer. With regard to electrical properties, the overall leakage increased when Zr was doped on the upper layer (i.e. Al/ZrN/Y2O3+Zr/Y2O3/p-Si). Finally, regarding the Schottky emission mechanism, we compared and analyzed the samples of the same DC power and same annealing temperature. We found that the barrier height was higher when Zr was doped on the bottom layer (i.e. Al/ZrN/Y2O3/Y2O3+Zr/p-Si). The higher barrier height may be the dominant factor to result in a lower leakage current.
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43

Chen, Yueh-Feng, and 陳岳鋒. "Study of Pd Nanocrystal Embedded in High-k Material for Nonvolatile Memory Application." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/12211158549442810532.

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碩士
逢甲大學
電子工程所
99
The Pd metal deposited on tunneling oxide can form nanocrystals by a subsequent annealing process. In this thesis, silicon oxide and hafnium aluminum oxide with different doped of aluminum were used as tunneling oxides, and applied on metal oxide semiconductor (MOS) capacitor and thin film transistor device. We focus on the effect of high temperature annealing on the electrical characteristic of MOS structure with different tunneling oxide, and the memory characteristic of TFT device. For MOS structure, the worse memory characteristics mainly are due to leakage current paths and shallow traps in tunneling oxide around Pd nanocrystals. The different expansion coefficients between Pd metal and silicon oxide/hafnium aluminum oxide induce defects in tunneling oxide and worsen the memory characteristic. Hafnium aluminum oxide as tunneling oxide of MOS structure can attain better memory characteristics as compared with the ones with SiO2 or HfO2 tunneling oxide. For TFT memory device, a memory characteristic can be obtained. However, the poor quality at the interfaces between tunneling oxide and Si substrate results in the reliability problems.
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44

HSIEH, CHI-WEN, and 謝啟文. "In-situ Monitoring the Etching Process of High-K Material by Modulation Ellipsometer." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/49215270794215308198.

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45

Wang, Yanzhen. "Investigation of electrical and material characteristics of high-k / III-V MOS devices and SiOx ReRAMs." 2013. http://hdl.handle.net/2152/21961.

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In the past few decades, Si-based CMOS technology is approaching to its physical quantum limit by scaling down the gate length and gate oxide thickness to achieve higher drive current for low power and high speed application. High k/III-V stack provides an alternative solution because III-V based metal-oxide-semiconductor (MOS) devices have higher drive current due to the higher electron mobility than silicon. Also high k oxides lower the gate leakage current significantly due to larger thickness under the same equivalent oxide thickness (EOT) compared with SiO₂ beyond the 22 nm node. The main obstacle for high k/III-V based MOSFETs is the lack of high quality, thermodynamically stable insulators that passivate the interface, which is also the main driving force in the research area of high k/III-V stack. One of the main focuses of this dissertation is developing a fabrication process flow to lower the interface trap density to enhance the performance of MOSFETs with high k oxides on III-V substrates. Also, an emerging memory device with SiO[subscript x] is also developed. This device can be electrically switched between a high-resistance state (HRS, or OFF-state) and a low-resistance state (LRS, or ON-state). Also it shows high potential for next generation nonvolatile memories due to its small cell area, fast write/erase time, low write voltage, good endurance and scalability. The other main focuses of this dissertation is studying the electroforming, set/reset voltages and passivation issue in this resistive random access memory (RRAM or ReRAM). The first part of this dissertation is about lowering the interface trap density of high k/III-V stack by using a thin layer of Al₂O₃ or LaAlO₃. ALD Al₂O₃/HfO₂ bi-layer gate oxide with different Al₂O₃ thickness (0, 5, 10Å) was deposited. Also ALD LaAlO₃/HfO₂ bi-layer gate oxide with different LaAlO₃ thickness (0, 5, 10, 20, 30, 42Å) was deposited. The total EOT of the bi-layer was maintained at ~1.8nm. Also single La[subscript x]Al[subscript 1-X]O (X =0.25, 0.33, 0.5, 0.66, 0.75) gate dielectric with different La doping level was deposited (EOT=2.5±0.4nm). Device characteristics are compared by using different thickness of interfacial layer. The second part of this dissertation is about F incorporation into high k oxide by using SF₆ plasma. The effect of SF₆ plasma treatment of HfO₂ on III-V substrates is demonstrated. Also effect of different plasma power and different treatment time of SF₆ plasma is studied to optimize plasma conditions. High k bilayer (Al₂O₃/HfO₂) is also used to further improve the device performance by better interface passivation with Al₂O₃. HfO₂ gate oxide dielectric is also engineered using SF₆ plasma treatment to incorporate more F. The third part is a study of III-V tunneling FET using In[subscript 0.7]Ga[subscript 0.3]As p-n junction. The device performance with different n doping concentration is compared. Higher n doping concentration will increase the drive current by reducing the tunneling width while too higher n doping concentration results in tunneling in the middle of p-n junction and significantly increase the subthreshold swing. The forth part is the electroforming, set/reset and passivation study of ReRAM device with SiO[subscript x]. Different methods to reduce the electroforming voltage are developed. Set/reset process is also studied and a possible model is proposed to explain the set/ reset process. A new device structure without sidewall edge is studied for passivation and application in air. The final part is the summary of Ph.D work and also suggestions for future work are discussed.
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46

Li, Ming-Han, and 李明翰. "Au Nanocrystal MOS Charge Storage Device By Using High-K Material As Tunneling Layer." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/67629614972670025679.

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碩士
國立臺灣大學
電子工程學研究所
94
The Au nanocrystal charge storage device by using High-K material as tunneling layer will be investigated in both C-V and Retention measurement to realize how the charge is programmed, erased and leaked. The tunneling layer material, such as HfO2 and HfSiO2, will be examined by XRD, IV, and CV measurement after different temperature annealing. The crystallization phenomenon is observed in HfO2 at high temperature. This phenomenon will decrease the performance of our device. In order to avoid crystallization, we use chemical redundant deposition to fabricate Au nano-dots. Because this process can be done in room temperature, we can keep HfO2 away from high temperature process. Owing to the high permittivity, HfO2 can be thicker than SiO2 in the same equivalent oxide thickness (EOT) and reduce the leakage current from Au nano-dots to silicon substrate. Thus, the retention of device by using HfO2 as tunneling layer is two times better than that by using SiO2 as tunneling layer. Another way to avoid crystallization is to change tunneling layer from HfO2 to HfSiO2. The crystallization phenomenon is not observed in HfSiO2 after high temperature annealing. At last, we are able to fabricate different density of Au dots in devices by using HfSiO2 as tunneling layer by controlling the deposition time. In this way, we can examine the relationship between the stored charge and the density of Au nano-dots.
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47

Ye, Jia-hao, and 葉嘉豪. "Processing and Modeling of Integrated Passive Capacitor by High-K Material for RF Application." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/92967789638949632203.

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碩士
國立雲林科技大學
光學電子工程研究所
97
In this research, we fabricate passive device capacitor with thin film fabrication technology. In this thesis, first part is fabrication and discuss MIM( Metal-Insulator- Metal ) capacitor of BST( Barium Strontium Titanate ). First, we used thermal evaporation method to deposit nickel(Ni) and copper(Cu) on quartz substrate, next deposit BST thin film with sputter method and hot temperature annealing. Finally, we used thermal evaporation method to deposit metal layers of nickel(Ni), copper(Cu) and nickel(Ni) respectively, then the MIM capacitor is achieved. Measuring the S-parameters with vector network analyzer(VNA) to get the different dielectric constant and capacitance, these parameters changing depend on frequency(1MHz ~6GHz), finally the physical equivalent model of MIM capacitor is been extracted. Based on the experimental results, we found dielectric constant on 1GHz are 15.4, 15.5 and 11.6 of no annealing, annealing 500℃ and 600℃ respectively, dielectric constant reduce when frequency increase. Then build up precise one port MIM capacitor equivalent circuit model by Agilent ADS according to comparison between measure and model data. Second part is fabrication and discuss IDC( Interdigital Capacitor ) of BST( Barium Strontium Titanate ). Fabrication process of IDC is the same of MIM Capacitor, but no bottom electrode, Measuring the S-parameters after finish IDC Capacitor with vector network analyzer(VNA) to get the different capacitance with changing device parameters on the frequency range (10MHz ~20GHz), finally extract physical equivalent model. Based on the experimental results, we found IDC16 capacitance on 1GHz are 599fF, 586 fF, 573 fF and 586 fF of no annealing, annealing 500℃, 600℃ and 700℃ respectively, these shown a unobvious difference. When finger numbers are 5, 7 and 9, IDC capacitance are 393fF, 586fF and 670fF respectively. When finger length are 1 and 2mm, IDC capacitance are 419fF and 468fF respectively. When finger width are 0.1 and 0.2mm, IDC capacitance are 551fF and 671fF respectively. Then build up precise two port IDC capacitor equivalent model in Agilent ADS according to the comparison between measure and model data. Third part is fabrication and discuss the CPW( Coplanar Waveguide ) of BST( Barium Strontium Titanate ), fabrication process of CPW is the same of IDC Capacitor. The purpose of CPW experiment is to extract dielectric constant of dielectric material. Based on the experimental results, dielectric constant is in the range of 4~7.5, approach the dielectric constant of quartz substrate, so equations are not precise on thin film fabrication technology, but get precise on thick film fabrication technology.
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48

Fong-Chi, Shih, and 石豐綺. "Study on LTPS-TFT Flash Memory using High-k Material as Charge Trapping Layer." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/07856442760214408383.

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碩士
國立交通大學
電子工程系所
96
In this thesis, electrical characteristic and Reliability of low temperature poly- silicon thin film transistor nonvolatile flash memory have studied, including programming/erasing speed, retention, endurance, retention after cycling and programming disturbances. First, three kinds of high-k materials, SiNx, Al2O3 and Hf-silicate, respectively, were applied for charge trapping layer of n-channel TFT memories. The fabricated memory devices show great retention and disturbance characteristics, attributed to the thick tunneling oxide. Among these three materials, Al2O3 performs best. Then, the same three kinds of materials as mentioned above were applied for p-channel TFT flash memories. The p-channel memory devices show better programming speed, programming voltage and data retention ability than n-channel ones, result in the lowering of power dissipation. Among all p-channel memory devices, Al2O3 performs best, also. Last, the n-channel devices after NH3 plasma treatment show obviously improvement on endurance and data retention.
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49

Yang, Tsung-Yuan, and 楊宗元. "The Study of Flash Memory with High-K Material and Nano-crystal Trapping Layer." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/44176968672899862260.

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碩士
國立交通大學
電子工程系所
94
In this thesis, first a tri-gate 55nm SONOS-type memories on SOI with HfSiOx nanocrystal trapping layers was proposed and demonstrated. We use CHE programming, FN programming, BTBHH erasing and FN erasing for the memory operation. Experimental results reveal that large memory windows, relative high P/E speed and good retention can achieve for SONOS-type memories and it is fully compatible to current CMOS technologies. In summary, tri-gate 55nm SONOS-type memories on SOI are the candidates used for the high density storage application. Then, a SONOS-type memories by using high-κ dielectric materials Lanthanum oxide trapping layers was proposed and demonstrated. We use CHE programming and BTBHH erasing for the memory operation. Experimental results reveal that large memory windows, relative high P/E speed and good retention can achieve for SONOS-type memories. In summary, La2O3 are the candidates used for the trapping layers for the SONOS-type memories and two-bit application. Finally, a SONOS-type memories by using high-κ dielectric materials Praseodymium oxide trapping layers was proposed and demonstrated. The SONOS-type Pr2O3 flash memories exhibit that they have large memory windows, relative high P/E speed but poor retention.
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50

Chen, Yen-Ting. "A study of electrical and material characteristics of high-k / III-V MOSFETs and SiO2 RRAMs." 2012. http://hdl.handle.net/2152/19623.

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Aggressive downscaling of complementary metal-oxide-semiconductor (CMOS) transistors has pushed Si-based transistors to their limit. III-V materials have much higher electron mobility compared to Si, which can potentially provide better device performance. Therefore, III-V semiconductor materials have been actively investigated as alternative channel materials, which can extend Moore’s law on CMOS scaling beyond the 22 nm node not only by relying on scaling. Meanwhile, conventional silicon dioxide cannot easily meet the requirement for the scaling of the equivalent oxide thickness; as a result, various high dielectric constant (high-k) materials have been incorporated onto the III-V semiconductor substrate. Nevertheless, the key challenges for high-k/III-V MOSFETs still need to be solved in order to implement high performance high-k/III-V MOSFETs. Those challenges are the lack of high quality and thermodynamically stable insulators that passivate the gate dielectric/III-V interface, compatible III-V p-type MOSFETs, and reliability issue of III-V MOSFETs, etc. The main focus of this dissertation is to develop proper fabrication processes and structures for III-V MOSFETs devices that result in good interface quality and high device performance. Firstly, we studied the effect of interfacial chemistry on ZrO2/InGaAs gate stack comprehensively, comparing ALD ZrO2 with H2O vs. O3 as the oxidizer. We found that the amount of oxygen is critical to form a good interface. Excessive oxygen concentration, e. g. using O3 as the ALD precursor, induces III-V native oxides at the interface. The second part of this dissertation focuses on the III-V MOSFETs with various IPLs. Various IPLs have been demonstrated, for example, a thin PVD Si IPL, and ALD Al2O3, HfAlOx, and ZrAlOx. Those IPLs are demonstrated to be effective interfacial dielectric layers to improve device performance, including frequency dispersion, SS, Ion, effective channel mobility, and reliability. The third part of this study highlights a novel CF4 post-gate plasma treatment on III-V MOSFETs. Fluorine incorporation was demonstrated on various high-k/III-V gate stacks and achieved significant improvements, including Al2O3/In0.53Ga0.47As, Al2O3/InP, HfO2/In0.53Ga0.47As, and HfO2/InP. Detailed physical analysis, electrical characterization and device performance were carried out. With F incorporation, we have successfully developed excellent interface quality of high-k/III-V MOSFETs. As a result, high-performance III-V MOSFETs have been realized. Finally, emerging non-volatile memories, RRAMs, have been demonstrated. We addressed its conducting mechanism by conducting various experiments and purposed a model for SiOx RRAMs: the conducting filament is randomly formed within the SiOx at the sidewall edge, depending on pre-existing defects. Moreover, the rupture/recovery could occur anywhere along the conducting filament, depending on a random process that determines the location of the weak spot along the conducting filament. In addition, we improved SiO2-based RRAM by incorporating a thin silicon layer onto its sidewall. This technique significantly reduced the electroforming voltage and instability of HRS current of SiO2-based RRAMs. Consequently, a tri-state pulse endurance performance over 106 cycles has been demonstrated and the data stored had good read disturb immunity and thermal disturbance.
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