Дисертації з теми "Dielectrics and semiconductors"
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1
Vaklev, Nikolay Lyubomirov. "Organic field-effect transistors with printed dielectrics and semiconductors." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/44879.
Повний текст джерелаАнотація:
This thesis presents the development of organic field-effect transistors with printed dielectric and semiconductors. The device architecture was bottom-gate bottom-contact. The electrodes were fabricated via standard photolithography. The first milestones were to gravure-coat the dielectric and structure it with photolithography. Dielectric formulations were screened for their ability to photopattern with radical photoinitiators. Variable processing conditions were also investigated such as annealing time and temperature. The preferred formulation and processing conditions gave ca. 130 nm thick dielectric films and 1-2 nm root-mean-square surface roughness. The dielectric films were tested in parallel capacitors and field-effect transistors. For comparison, the dielectric was also spin-cast and processed analogously to the gravure-coated films. Under the same conditions gravure-coating gave films with equal uniformity and insulating properties as spin-casting. Transistors were prepared with thermally-evaporated pentancene and TIPS-pentacene (6,13-bis(triisopropylsilylethynyl) pentacene) via spin- or zone-casting. The measured mobilities were amongst the highest reported in the literature for this material set and device architecture. The highest transistor mobility with TIPS-pentacene was achieved by blending the semiconductor with poly(a-methylstyrene) (PaMS). Device characteristics such as mobility, threshold voltage and sub-threshold swing voltage were calculated and their evolution with blending ratio followed. The semiconductor was either spin-cast onto pre-deposited PaMS layers with different thickness or TIPS-pentacene was blended with PaMS already in the ink. The work concluded with structured gravure-printing of the dielectric and semiconductor. Dielectric inks with different viscosity were printed and print quality investigated. The film thickness ranged between 60 and 500 nm. Exemplary films were used in the fabrication of transistors and complementary inverters. TIPS-pentacene was directly blended with polymer binders and printed.
2
Ravindran, Ramasamy. "Deposition and characterization of high permittivity thin-film dielectrics." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4530.
Повний текст джерелаАнотація:
Thesis (M.S.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 17, 2009) Includes bibliographical references.
3
Sung, Taehyun. "Variable frequency microwave curing of polymer dielectrics on metallized organic substrates." Thesis, Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180423/unrestricted/sung%5ftaehyun%5f200312%5fms.pdf.
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4
Li, Chunxia, and 李春霞. "A study on gate dielectrics for Ge MOS devices." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B43703872.
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5
Li, Chunxia. "A study on gate dielectrics for Ge MOS devices." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43703872.
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6
Huang, Amy. "On the plasma induced degradation of organosilicate glass (OSG) as an interlevel dielectric for sub 90 nm CMOS /." Online version of thesis, 2008. http://hdl.handle.net/1850/5899.
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7
Zeng, Xu, and 曾旭. "Electrical reliability of N-Mos devices with N2O-based oxides as gate dielectrics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31235475.
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8
Zeng, Xu. "Electrical reliability of N-Mos devices with N2O-based oxides as gate dielectrics /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1966980X.
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9
Lin, Limin. "A study of gate dielectrics for wide-bandgap semiconductors GaN & SiC /." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B3932252X.
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10
Lin, Limin, and 林立旻. "A study of gate dielectrics for wide-bandgap semiconductors: GaN & SiC." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B3932252X.
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11
Rämer, Anika [Verfasser]. "Excitation and Relaxation Dynamics in Laser-Excited Semiconductors and Dielectrics / Anika Rämer." München : Verlag Dr. Hut, 2017. http://d-nb.info/1139538071/34.
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12
Pinto, Jason Christopher. "Field-effect transistors from discotic liquid crystal semiconductors and polymer brush dielectrics." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612816.
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13
Othman, Maslina. "Spectroscopic ellipsometry analysis of nanoporous low dielectric constant films processed via supercritical carbon dioxide for next-generation microelectronic devices." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4879.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 24, 2009) Vita. Includes bibliographical references.
14
Song, Seung-chul. "Advanced oxynitride and silicon nitride gate dielectrics for ULSI CMOS technology /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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15
Kim, Ŭn-ji. "Interface and defect study of high permittivity dielectrics on Si and III-V semiconductors /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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16
Бондаренко, И. Н., В. А. Николаенко, and А. В. Полищук. "The cavity with the Tunnel Diodes and Corbino-Electrodes for Analyze Dielectrics and Semiconductors." Thesis, Sumy State University, 2019. http://openarchive.nure.ua/handle/document/10409.
Повний текст джерелаАнотація:
. Study of nano structures is importance as bind the nanotechnology and applying. Many methods and tools use here (EPA); (NMR); AFM, X-ray so on. The high frequency (HF) resonance method at low temperature is sensitive and exact method because high quality of resonance and neglecting both the device noise and losses in matter. The “gaga – nano” conception take a place here too. The using little tunnel diodes as the generator and the detector in cavity is ideal for that aim. In this project cavity bottom is system of coaxial insulated rings (Corbino geometry) which applied as the low frequency (LF) analyzer as well as the modulator of HF field. So, we proposed HF - LF mini- analyzer for study of matter, the composition of device is given.
17
Ligor, Octavian. "Reliability of the Scanning Capacitance Microscopy and Spectroscopy for the nanoscale characterization of semiconductors and dielectrics." Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0008/these.pdf.
Повний текст джерелаАнотація:
Ce travail a été dédié à l'étude expérimentale des mesures capacitives avec le microscope à force atomique (AFM) pour la caractérisation des profils des dopants dans des structures semiconductrices et pour la caractérisation des oxydes minces. La SCM est une méthode de caractérisation très utile pour les mesures de défaillance des profils des dopants, par exemple pour vérifier si des différentes étapes technologique s comme l'implantation des dopants dans des substrats semiconducteurs a été correctement effectuée. Nous avons démontré le potentiel de la SCM pour la caractérisation des profils des dopants en utilisant des échantillons de test qui couvrent à peu prés toutes les structures semiconductrices rencontrées dans l'industrie de la microélectronique: des profils des dopants, de type escalier, des puits quantiques, des jonctions p-n. Des images qualitatives ont été obtenues sur des échantillons contenant des profils des dopants des concentrations entre 2. E+15 at. Cm-3 et 5. E+19cm-3. Nous avons montré que la SCM est capable de détecter des puits quantiques avec une épaisseur d'environ 7 nm. La SCM est capable de faire la différence entre les dopants de type n et les dopants de type p. Tous ces résultats confirment l'utilité de la SCM comme méthode de caractérisation qualitative des profils des dopants à nano-échelle. Nous avons aussi étudié les paramètres expérimentaux qui jouent un rôle dans l'interprétation et la reproductibilité du signal capacitif: la lumière laser parasite provenant du système de détection de l'AFM, des couplage capacitifs parasites, les problèmes de contact entre la sonde AFM et l'échantillon, l'influence des champs électriques forts générés par la sonde AFM, la topographie des échantillons, la qualité et les propriétés de l'oxyde de grille. Nous avons proposé des solutions pour l'élimination de tous ces facteurs parasites et pour l'avancement de la SCM vers des mesures reproductibles et quantifiablesThis work was devoted to the experimental study of the scanning capacitance microscopy (SCM) and spectroscopy (SCS) for the mapping of the dopants in the semiconductor structures and for the characterization of thin oxides. SCM has appeared to be a very powerful technique for doping mapping as long as qualitative images are needed, for example in order to check whether fabrication steps like implantations have been correctly operated during the fabrication of devices (presence or absence of doping of a given type in a region where it should be present). When quantitativity is needed, the only way of performing a calibration of SCM images for dopant mapping seems to grow exactly the same oxide on two different samples, one being a calibration sample from which a semi-calibration curve associating doping levels and SCM signal levels will be measured and applied to the unknown sample (semi-calibration). We have shown the capabilities of SCM for dopant mapping using a series of experimental situations and test samples covering almost all frequently encountered structures in the industry of silicon microelectronics : doping staircases of p-type and n-type structures, quantum wells and p-n junctions. Qualitative images have been obtained for a wide range of doping levels between 2. E+15 at. Cm-3 to 5. E+19 at. Cm-3. SCM is able to detect quantum wells of ~ 7 nm width. SCM is also able to differentiate between dopants of different type (p-type or n-type). All these results confirm the usefulness of SCM as a qualitative imaging technique. We have studied the experimental parameters playing a role in the interpretation and reproducibility of SCM signal: stray light, stray capacitance, the tip-sample contact, the influence of strong electrical fields, the sample’s topography, the quality and the properties of the top oxide. We have proposed solutions for eliminating all these parasitic factors and for rendering the SCM measurements reproducible and quantitative
18
Chan, Yiu Him. "Effect of dopants and gate dielectrics on charge transport and performance of organic thin film transistor." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1450.
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19
Koslowski, Nico [Verfasser], Jörg J. [Akademischer Betreuer] Schneider, and Barbara [Akademischer Betreuer] Albert. "Approaching metal oxide high-k dielectrics and semiconductors by solution-processing of molecular precursors / Nico Koslowski ; Jörg J. Schneider, Barbara Albert." Darmstadt : Universitäts- und Landesbibliothek, 2021. http://d-nb.info/1241741581/34.
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20
Sturm, Chris, Rüdiger Schmidt-Grund, Vitaly Zviagin, and Marius Grundmann. "Temperature dependence of the dielectric tensor of monoclinic Ga2O3 single crystals in the spectral range 1.0–8.5 eV." American Institute of Physics, 2017. https://ul.qucosa.de/id/qucosa%3A25613.
Повний текст джерелаАнотація:
The full dielectric tensor of monoclinic Ga2O3 (β-phase) was determined by generalized
spectroscopic ellipsometry in the spectral range from 1.0 eV up to 8.5 eV and temperatures in the
range from 10K up to 300K. By using the oriented dipole approach, the energies and broadenings of
the excitonic transitions are determined as a function of the temperature, and the exciton-phonon coupling
properties are deduced.
21
Ukirde, Vaishali. "Trapping of hydrogen in Hf-based high κ dielectric thin films for advanced CMOS applications". Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc5114/.
Повний текст джерелаАнотація:
In recent years, advanced high κ gate dielectrics are under serious consideration to replace SiO2 and SiON in semiconductor industry. Hafnium-based dielectrics such as hafnium oxides, oxynitrides and Hf-based silicates/nitrided silicates are emerging as some of the most promising alternatives to SiO2/SiON gate dielectrics in complementary metal oxide semiconductor (CMOS) devices. Extensive efforts have been taken to understand the effects of hydrogen impurities in semiconductors and its behavior such as incorporation, diffusion, trapping and release with the aim of controlling and using it to optimize the performance of electronic device structures. In this dissertation, a systematic study of hydrogen trapping and the role of carbon impurities in various alternate gate dielectric candidates, HfO2/Si, HfxSi1-xO2/Si, HfON/Si and HfON(C)/Si is presented. It has been shown that processing of high κ dielectrics may lead to some crystallization issues. Rutherford backscattering spectroscopy (RBS) for measuring oxygen deficiencies, elastic recoil detection analysis (ERDA) for quantifying hydrogen and nuclear reaction analysis (NRA) for quantifying carbon, X-ray diffraction (XRD) for measuring degree of crystallinity and X-ray photoelectron spectroscopy (XPS) were used to characterize these thin dielectric materials. ERDA data are used to characterize the evolution of hydrogen during annealing in hydrogen ambient in combination with preprocessing in oxygen and nitrogen.
22
Bothschafter, Elisabeth Monika Ludmilla [Verfasser], Reinhard [Akademischer Betreuer] Kienberger, and Jonathan J. [Akademischer Betreuer] Finley. "Femtosecond and Attosecond Electron Dynamics in Semiconductors and Dielectrics / Elisabeth Monika Ludmilla Bothschafter. Gutachter: Jonathan J. Finley ; Reinhard Kienberger. Betreuer: Reinhard Kienberger." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1051734843/34.
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23
Sundaram, Venkatesh. "Advances in electronic packaging technologies by ultra-small microvias, super-fine interconnections and low loss polymer dielectrics." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28141.
Повний текст джерелаАнотація:
Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2009.Committee Chair: Tummala, Rao; Committee Member: Iyer, Mahadevan; Committee Member: Saxena, Ashok; Committee Member: Swaminathan, Madhavan; Committee Member: Wong, Chingping.
24
Fratelli, Ilaria. "Flexible oxide thin film transistors: device fabrication and kelvin probe force microscopy analysis." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13538/.
Повний текст джерелаАнотація:
I transistor a film sottile basati su ossidi amorfi semiconduttori sono ottimi candidati nell'ambito dell'elettronica su larga scala. Al contrario delle tecnologie basate su a-Si:H a poly-Si, gli AOS presentano un'elevata mobilità elettrica (m > 10 cm^2/ Vs) nonostante la struttura amorfa. Inoltre, la possibilità di depositare AOS a basse temperature e su substrati polimerici, permette il loro impiego nel campo dell'elettronica flessibile.
Al fine di migliorare questa tecnologia, numerosi TFT basati su AOS sono stati fabbricati durante 4 mesi di attività all'Università Nova di Lisbona. Tutti i transistor presentano un canale formato da a-GIZO, mentre il dielettrico è stato realizzato con due materiali differenti: Parylene (organico) e 7 strati alternati di SiO2
e SiO2 + Ta2O5. I dispositivi sono stati realizzati su substrati
flessibili sviluppando una nuova tecnica per la laminazione e la delaminazione di fogli di PEN su supporto rigido. L'ottimizzazione del processo di fabbricazione ha permesso la realizzazione
di dispositivi che presentano caratteristiche paragonabili a quelle previste per TFT costruiti su substrati rigidi (m = 35.7 cm^2/Vs; VON = -0.10 V; S = 0.084 V/dec).
Al Dipartimento di Fisica dell'UNIBO, l'utilizzo del KPFM ha permesso lo studio a livello microscopico delle prestazioni presentate dai dispositivi analizzati. Grazie a questa tecnica di indagine, è stato possibile analizzare l'impatto delle resistenze di contatto sui dispositivi meno performanti e identificare l'esistenza di cariche intrappolate nei TFT basati su Parylene.
Gli ottimi risultati ottenuti dall'analisi KPFM suggeriscono un futuro impiego di questa tecnica per lo studio del legame tra stress meccanico e degradazione elettrica dei dispositivi. Infatti, la comprensione dei fenomeni microscopici dovuti alla deformazione strutturale sarà un passaggio indispensabile per lo sviluppo dell'elettronica flessibile.
25
Rossi, Leonardo. "Flexible oxide thin film transistors: fabrication and photoresponse." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14542/.
Повний текст джерелаАнотація:
Gli ossidi amorfi semiconduttori (AOS) sono nuovi candidati per l’elettronica flessibile e su grandi aree: grazie ai loro legami prevalentemente ionici hanno una mobilità relativamente alta (µ > 10cm^2/Vs) anche nella fase amorfa. Transistor a film sottile (TFT) basati sugli AOS saranno quindi più performanti di tecnologie a base di a-Si e più economici di quelle a base di silicio
policristallino. Essendo amorfi, possono essere depositati a basse temperature e su substrati polimerici, caratteristica chiave per l’elettronica flessibile e su grandi aree. Per questa tesi, diversi TFT sono stati fabbricati e caratterizzati nei laboratori del CENIMAT all’Università Nova di Lisbona sotto la supervisione del Prof. P. Barquinha. Questi dispositivi sono composti di contatti in molibdeno, un canale semiconduttivo di ossido di zinco, gallio e indio (IGZO) e un dielettrico composto da 7 strati alternati di SiO2 e SiO2+Ta2O5. Tutti i dispositivi sono stati depositati mediante sputtering su sostrati flessibili (fogli di PEN). Le misure tensione-corrente mostrano che i dispositivi mantengono alte mobilità (decine di 10cm^2/Vs) anche quando fabbricati a temperature inferiori a 200°C. Si è analizzato il funzionamento dei dispositivi come fototransistor rilevando la risposta alla luce ultravioletta e in particolare la loro responsività e spostamento della tensione di soglia in funzione della lunghezza d’onda incidente. Questi risultati consentono di formulare ipotesi sul comportamento dei dispositivi alla scala microscopica. In particolare, indicano che i) la mobilità del canale non è influenzata dall’illuminazione, ii) sia l'IGZO sia il Ta2O5 contribuiscono al processo di fotoconduttività e iii) il processo di fotogenerazione non è adiabatico. La tesi contiene inoltre una descrizione del processo di ricombinazione e presenta un’applicazione pratica di tali dispositivi in un circuito per RFID. Infine, esplora la possibilità di migliorarne la flessibilità e le prestazioni.
26
Spisni, Giacomo. "Radiation-sensitive OXide semiconductor Field Effect Transistor (ROXFET): a novel thin-film device for real-time and remote ionizing radiation detection." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24394/.
Повний текст джерелаАнотація:
Nowadays, ionizing radiation detectors find application in a wide range of contexts, spanning from industry to healthcare and security. In this background, the next generation of ionizing radiation sensors require devices that are accurate, light-weight, relatively inexpensive and capable to be read-out in real-time and remotely. In recent years, research groups at the University of Bologna and the NOVA University of Lisbon (Portugal) have developed Radiation-sensitive OXide-semiconductor Field-Effect Transistors (ROXFET) to be employed as fast, real-time x-ray dosimetry detection systems. The ROXFET operation relies on the principle that, upon exposure to radiation, excitons are generated in the dielectric and separated into hole and electron charge carriers. While electrons are able to diffuse out of the dielectric layer, hole charges get trapped and contribute to the field-effect in the semiconductor channel. Macroscopically, such contribution is observable as a shift in transistor threshold voltage toward negative values, which turns out to be proportional to the absorbed radiation dose. In laboratory tests, ROXFET devices proved to be sensitive in a wide energy range and capable of providing reliable information about their radiation exposure history. Furthermore, the design of ROXFET can be integrated on a flexible substrate and read in real-time as a passive radiofrequency tag. Aim of this thesis work was to contribute to the development of the ROXFET technology. To this end, I carried out multiple characterization tests on recently fabricated samples, revealing how they outperformed previously observed radiation sensitivities. Later on, I worked in a clean-room facility to fabricate new ROXFET experimental samples by leveraging the knowledge acquired from previous observations.
27
Ramme, Mark. "Ultrafast Laser Material Processing For Photonic Applications." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5846.
Повний текст джерелаАнотація:
Femtosecond Laser Direct Writing (FLDW) is a viable technique for producing photonic devices in bulk materials. This novel manufacturing technique is versatile due to its full 3D fabrication capability. Typically, the only requirement for this process is that the base material must be transparent to the laser wavelength. The modification process itself is based on non-linear energy absorption of laser light within the focal volume of the incident beam. This thesis addresses the feasibility of this technique for introducing photonic structures into novel dielectric materials. Additionally, this work provides a deeper understanding of the light-matter interaction mechanism occurring at high pulse repetition rates. A novel structure on the sample surface in the form of nano-fibers was observed when the bulk material was irradiated with high repetition rate pulse trains. To utilize the advantages of the FLDW technique even further, a transfer of the technology from dielectric to semiconductor materials is investigated. However, this demands detailed insight of the absorption and modification processes themselves. Experiments and the results suggested that non-linear absorption, specifically avalanche ionization, is the limiting factor inhibiting the application of FLDW to bulk semiconductors with today's laser sources.Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
28
Osei-Yiadom, Eric. "Effects of Plasma, Temperature and Chemical Reactions on Porous Low Dielectric Films for Semiconductor Devices." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc33192/.
Повний текст джерелаАнотація:
Low-dielectric (k) films are one of the performance drivers for continued scaling of integrated circuit devices. These films are needed in microelectronic device interconnects to lower power consumption and minimize cross talk between metal lines that "interconnect" transistors. Low-k materials currently in production for the 45 and 65 nm node are most often organosilicate glasses (OSG) with dielectric constants near 2.8 and nominal porosities of 8-10%. The next generation of low-k materials will require k values 2.6 and below for the 45 nm device generation and beyond. The continuous decrease in device dimensions in ultra large scale integrated (ULSI) circuits have brought about the replacement of the silicon dioxide interconnect dielectric (ILD), which has a dielectric constant (k) of approximately 4.1, with low dielectric constant materials. Lowering the dielectric constant reduces the propagation delays, RC constant (R = the resistance of the metal lines; C = the line capacitance), and metal cross-talk between wires. In order to reduce the RC constants, a number of low-k materials have been studied for use as intermetal dielectrics. The k values of these dielectric materials can be lowered by replacing oxide films with carbon-based polymer films, incorporating hydrocarbon functional groups into oxide films (SiOCH films), or introducing porogens in the film during processing to create pores. However, additional integration issues such as damage to these materials caused by plasma etch, plasma ash, and wet etch processes are yet to be overcome. This dissertation reports the effects of plasma, temperature and chemical reactions on low-k SiOCH films. Plasma ash processes have been known to cause hydrophobic films to lose their hydrophobic methyl groups, rendering them to be hydrophilic. This allows the films to readily absorb moisture. Supercritical carbon dioxide (SC-CO2) can be used to transport silylating agents, hexamethyldisilazane (HMDS) and diethoxy-dimethlysilane (DEDMS), to functionalize the damaged surfaces of the ash-damaged films. The thermal stability of the low-k films after SC-CO2 treatment is also discussed by performing in-situ heat treatments on the films. UV curing has been shown to reduce the amount of pores while showing only a limited change dielectric constant. This work goes on to describe the effect of UV curing on low-k films after exposing the films to supercritical carbon dioxide (CO2) in combination with tetramethylorthosilicate (TMOS).
29
Leyder, Stephanie. "Ionisation nonlinéaire dans les matériaux diélectriques et semiconducteurs par laser femtoseconde accordable dans le proche infrarouge." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4103/document.
Повний текст джерелаАнотація:
La microfabrication 3D par laser dans les matériaux à faible bande interdite néces- sitera l’utilisation d’impulsions intenses dans l’infrarouge proche et moyen. Cette étude expérimentale se concentre sur les spécificités de la physique d’ionisation nonlinéaire dans la gamme de longueur d’onde de 1300-2200nm. Contrairement aux semiconducteurs, l’ab- sorption nonlinéaire mesurée dans les diélectriques est indépendante de la longueur d’onde révélant ainsi l’importance accrue de l’ionisation par effet tunnel avec ces longueurs d’onde. Nous étudions également les rendements et les seuils d’ionisation multiphotonique et ava- lanche dans le silicium intrinsèque et dopé N. Les résultats couplés à l’observation des ma- tériaux irradiés montrent que les propriétés intrinsèques des semiconducteurs empêchent un dépôt d’énergie suffisamment confiné pour viser directement des applications de modifica- tion locale. Ce travail illustre les possibilités de micro-usinage laser 3D dans les diélectriques et les défis de l’extension de cette technique aux semiconducteurs3D laser microfabrication inside narrow gap solids like silicon will require the use of long wavelength intense pulses. This experimental study concentrates on the specificity of the nonlinear ionization physics with tightly focused femtosecond laser beams over a wa- velength range of 1300-2200nm. The measured nonlinear absorption is independent of the wavelength in dielectrics revealing the increased importance of tunnel ionization with long wavelength. This can open up an alternative to pulse shortening toward ultraprecision op- tical breakdown in dielectrics. Using n-doped silicon, we study the multiphoton-avalanche absorption yields and thresholds inside semiconductors. Also observations of the irradia- ted materials reveal that the intrinsic properties of semiconductors prevent efficient direct energy deposition in the bulk for applications. This work illustrates opportunities for 3D laser micromachining in dielectrics and challenges for its extension to semiconductors
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Howard, L. K. "A study of epitaxial growth of CaFâ†2 on silicon." Thesis, London South Bank University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352971.
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Yan, X. "Waves in layered semiconductor-dielectric structures." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492177.
Повний текст джерелаАнотація:
Objective is to theoretically and numerically analyze the full spectrum and properties of Transverse Magnetic eigenwaves in a parallel-plate waveguide containing a perfect/imperfect (de)magnetised semiconductor layer sandwiched between two dielectric slabs. The novel contributions in the thesis are summarised as follows. In a perfect demagnetised structure, dynamic modes exist in the frequency band w>cop . (plasma frequency) and two surface plasmonic modes exist in co
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Souza, Denise Criado Pereira de. "Estudo da morfologia e estrutura de filmes de oxinitreto de silício (SiOxNy) obtidos pela técnica de PECVD." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-09012008-145807/.
Повний текст джерелаАнотація:
Neste trabalho são apresentados resultados da caracterização estrutural e morfológica de filmes de oxinitreto de silício (SiOxNy) depositados pela técnica de deposição química a vapor assistida por plasma (PECVD) a baixa temperatura (320°C). O objetivo deste trabalho é relacionar a composição química de ligas amorfas de SiOxNy com suas propriedades ópticas, estruturais, morfológicas e mecânicas visando sua aplicação em dispositivos elétricos, optoeletrônica e microestruturas. A proposta é dar continuidade a trabalhos prévios desenvolvidos no grupo, que demonstraram a viabilidade de controlar a composição química e, como conseqüência, controlar as propriedades como o índice de refração, constante dielétrica e fotoluminescência de filmes de SiOxNy. As condições de deposição foram ajustadas de forma a obter dois tipos de material: filmes de SiOxNy de composição química controlável entre a do SiO2 e a do de Si3N4 e filmes de SiOxNy com composição rica em Si. O material foi caracterizado pelas técnicas de elipsometria, índice de refração por prisma acoplado, RBS (Rutherford Backscattering Spectroscopy), FTIR (Fourier Transform Infrared Spectroscopy), XANES (X-Ray Absorption Near Edge Spectroscopy) na borda K do Si, O e N, medida de stress residual e microscopia eletrônica de varredura (Scanning Electron Microscopy) e de transmissão (Transmission Electron Microscopy). Os resultados mostraram que os filmes com composição química intermediária entre a do SiO2 e a do Si3N4 apresentam arranjo estrutural estável com a temperatura, mantendo as ligações e a estrutura amorfa mesmo após tratamentos térmicos a 1000°C. Também fora demonstrada a possibilidade de obter um material com baixo stress residual e índice de refração ajustável entre 1,46 e 2, resultados ótimos para aplicações em MOEMS (micro-opto-electro- mechanical systems). Já nas amostras ricas em Si foi observada a formação de diferentes fases, sendo uma delas formada por aglomerados de Si e a outra por material constituído por uma mistura de ligações Si-O e Si-N. Este material apresenta a formação de nanocristais de Si, dependendo do conteúdo de Si e das condições do tratamento térmico, permitindo assim, sua aplicação em dispositivos emissores de luz.In this work results on the morphological and structural characterization of silicon oxynitride (SiOxNy) films deposited by plasma enhanced chemical vapor deposition technique (PECVD) at low temperature (320°C) are presented. The main goal is to correlate the chemical composition of amorphous SiOxNy alloys to their optical, structural, morphological and mechanical properties intending applications on electrical, optoelectronic and micromechanical devices. The proposal is to continue previous research developed in this group, which demonstrated the possibility of tuning the chemical composition and, consequently, the SiOxNy films properties such as refractive index, dielectric constant and photoluminescence by the precise control of the deposition parameters. The deposition conditions were adjusted in order to obtain to material types, SiOxNy films with tunable chemical composition between SiO2 and Si3N4 and silicon-rich SiOxNy. The characterization was performed by elipsometry, refractive index by coupled prism, RBS (Rutherford Backscattering Spectroscopy), FTIR (Fourier Transform Infrared Spectroscopy), XANES (X-Ray Absorption Near Edge Spectroscopy) on K edge of Si, O and N, residual stress measurement and Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The films with chemical composition between SiO2 and Si3N4 presented stable structural arrangement with temperature, maintaining the chemical bonds and the amorphous structure after high temperature annealing. Also the results demonstrated the possibility of producing a low residual stress material and an adjustable refractive index since in the 1.46 to 2 range, excellent result for MOEMS devices (micro-opto-electro- mechanical systems applications. For silicon rich-samples the formation of different phases was observed, one formed by Si clusters and other one by a mixture of Si-O and Si-N bonds. Depending on the Si content and on the annealing conditions this material can present nanocristals, results which allowed us to understand and to optimize this material for light emitting devices applications.
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Anwar, M. "Spectroscopic investigations of amorphous complex dielectric materials." Thesis, Brunel University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234036.
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Friar, Robert James. "Analysis, design, and measurement of on-wafer transmission line test structures /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Husain, M. N. "Analysis of single and coupled dielectric rib waveguides and discontinuities." Thesis, University of Bath, 1991. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280252.
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36
Doucet, David R. (David Raymond Joseph) Carleton University Dissertation Engineering Electrical. "Characterization of enhanced conductivity dielectrics for use in semiconductor devices." Ottawa, 1986.
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37
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.
Повний текст джерелаАнотація:
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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Sun, Zhuting. "Electron Transport in High Aspect Ratio Semiconductor Nanowires and Metal-Semiconductor Interfaces." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479821421998919.
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Ben, Taher Azza. "Strong Optical Field Ionization of Solids." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37151.
Повний текст джерелаАнотація:
Population transfer from the valence to conduction band in the presence of
an intense laser field is explored theoretically in semiconductors and dielectrics.
Experiments on intense laser driven dielectrics have revealed population transfer
to the conduction band that differs from that seen in semiconductors. Our
research explores two aspects of ionization in solids. (i) Current ionization
theories neglect coupling between valence and conduction band and therewith
the dynamic Stark shift. Our single-particle analysis identifies this as a potential
reason for the different ionization behaviour. The dynamic Stark shift increases
the bandgap with increasing laser intensities thus suppressing ionization to an
extent where virtual population oscillation become dominant. The dynamic
Stark shift plays a role dominantly in dielectrics which due to the large bandgap
can be exposed to significantly higher laser intensities. (ii) In the presence
of laser dressed virtual population of the conduction band, elastic collisions
potentially transmute virtual into real population resulting in ionization. This
process is explored in context of relaxation time approximation.
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Issac, Abey. "Photoluminescence Intermittency of Semiconductor Quantum Dots in Dielectric Environments." Doctoral thesis, Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200601267.
Повний текст джерелаАнотація:
The experimental studies presented in this thesis deal with the photoluminescence intermittency of semiconductor quantum dots in different dielectric environments. Detailed analysis of intermittency statistics from single capped CdSe/ZnS, uncapped CdSe and water dispersed CdSe/ZnS QDs in different matrices provide experimental evidence for the model of photoionization with a charge ejected into the surrounding matrix as the source of PL intermittency phenomenon. The distribution of the dark state lifetimes can be described by a power law over a wide range while that of bright state can be described by a power law at shorter times followed by an exponential decay. The lifetimes of the bright and dark states are influenced by the dielectric properties of the surrounding environment. Our experimental results show that the lifetime of the dark state increases with the dielectric constant of the matrix. This is very clear from the linear correlation between αoff and f (ε). We propose a self-trapping model to explain the increase of dark state lifetimes with the dielectric constant of the matrix. A charge will be more stabilized in a medium with high dielectric constant. An energetically more favourable state for an electron in a high dielectric medium decreases the return probability which eventually increases the duration of the off-time. Moreover, the self-trapping model establishes a general model for distribution of states in a matrix. We like to mention, that in the case of bright states, a qualitative observation is the cross over of the on-time power law behavior to an exponential one. The power law part of the decay is nearly matrix independent while the exponential decay, which limits the maximum on-time, strongly depends on dielectric properties of the environment. The exponential part of the on-time probability decays much faster in a high dielectric medium and there exists a linear relation between the time constant of the exponential decay and f (ε). Theoretical background has been provided for the observed results using the recently published DCET model which correlates PL intermittency of QDs with properties of the environment. This supports our previous conjecture of a general model for matrix controlled blinking process. The disagreement between experimentally observed dependence of αoff and f (ε) for different matrices with that of the static tunnelling model proposed by Verberk is due to the fact that the tunneling model considers only an electron transfer between a QD and spatially distributed trap states in vacuum. These states are already stabilized states. It does not assume any medium in between. Therefore, matrix dependent blinking kinetics can not be explained quantitatively by tunneling model even though tunneling between a QD and spatially distributed trap states gives a power law distribution for the blinking kinetics. DCET is a more general (dynamic) model. The bright and dark state parabolas contain QD, charge and the matrix. Therefore, this model could in principle explain matrix dependent blinking kinetics in a better way, for example, the energy difference between the minima of the bright and dark state parabolas (-ΔG0) is defined by the stabilization energy of the system provided by the matrix. However, due to lack of the relevant intrinsic parameters we did not compare this relationship and dependence qualitativelyBetrachtet man die Fluoreszenz einzelner Farbstoffmoleküle oder Halbleiternanokristalle bei kontinuierlicher Anregung, so stellt man fest, dass die im Zeitverlauf beobachtete Intensität einer stochastischen Variation unterliegt, d. h. dass das Chromophor zwischen emittierenden und nicht emittierenden Zuständen, auch Hell- und Dunkelzuständen genannt, hin- und herschaltet. Dieses als Blinken bekannte Phänomen ist physikalisch wie auch technologisch herausfordernd, lässt es doch einerseits die Realisierbarkeit einer Reihe von quantenoptischen Anwendungen, so z. B. auf dem Gebiet der Quantenkryptographie, dem Quantum Computing oder der optischen Schaltungstechnik auf Basis einzelner Quantenobjekte, in naher Zukunft möglich erscheinen. Andererseits setzt es gewissen Anwendungen, die auf die permanente Sichtbarkeit des Chromophors aufbauen, Grenzen, so zum Beispiel der Verwendung als Lumineszenzmarker in der medizinischen Diagnostik. Weiterhin ist festzustellen, dass das Blinken kritisch von den äußeren Bedingungen und von den Umgebungsparametern abhängt. Aus diesen und anderen Gründen ist ein fundamentales Verständnis der physikalischen Ursachen und der Wechselwirkungsprozesse unerlässlich. Die Forschung dazu steckt noch in den Kinderschuhen. Basierend auf umfangreiche Messungen der Fluoreszenzzeitreihen einzelner Nanokristalle aus CdSe und CdSe/ZnS in verschiedenen Umgebungen, zeigt diese Dissertation exemplarisch den Einfluss der Dielektrizitätsparameter auf das Blinken. Zur Erklärung des Sachverhalts wird ein so genanntes Self-Trapping-Modell zu Rate gezogen. Demnach kommt es zu einer Ionisation des Quantenobjekts und anschließender Ladungstrennung, woraufhin die abgetrennte Ladung für eine gewisse Zeit in der Umgebung lokalisiert bleibt. Die Dauer der Lokalisierung und damit der emittierenden und nicht emittierenden Perioden hängt von der dielektrischen Funktion des umgebenden Materials ab. Dies ist als direkter Nachweis für den photoinduzierten Ladungstransfer als Ursache des Fluoreszenzblinkens zu deuten. Die Arbeit demonstriert, dass die experimentellen Zeitreihen die charakteristischen Merkmale eines diffusionsgesteuerten Ladungstransferprozesses besitzen und nimmt dabei den gegenwärtigen wissenschaftlichen Diskurs über geeignete theoretische Modelle des Fluoreszenzblinkens auf
41
Boudreau, Marcel G. "Optical coatings for improved semiconductor diode laser performance /." *McMaster only, 1997.
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42
Poolamai, Nipapan. "Integration of high-K gate dielectrics in silicon based semiconductor technology." Thesis, University of Newcastle Upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490153.
Повний текст джерелаАнотація:
To integrate high-K gate dielectrics into metal-oxide-semiconductor field-effect transistors (MOSFETs), challenges arise due to properties of high-K gate dielectrics themselves. High temperature processes after the formation of high- K gate dielectrics have been a major concern. Investigations on process sequences of MOSFETs with high-K gate dielectrics have been carried out and a MOSFET process flow with reduced thermal budget has been proposed. Furthermore, the application of high-K gate dielectrics to silicon carbide (SiC) tech.,.'1ology has been proposed recently due to the inferior Si02/SiC interface quality and reliability problems of SiC MOS power devices. Therefore, a high-Kgate stack structure on SiC has also been investigated. The effects of process sequences in conventional and replacement gate process on device characteristics of 70-nm MOSFETs with different high-K gate dielectric constant were studied by using process and device simulation, SILVACO TCAD software. It was found that high-K MOSFETs created by replacement gate process have a degradation in short channel performance whilst less short-chi:mnel effects are found in high-K MOSFETs created by conventional process. In addition, the use of high-K dielectrics in MOSFETs affects DC characteristics and gate delay of circuit performfu''1ce. However, with different process sequences, the device and circuit performance exhibited differing effects. This may be due to the changes of the doping and profile in the silicon substrate implicit in the fabrication sequences, and optimised retrograde channel doping profile may help to improve device performance of high-K devices. The PMOS process flow with reduced thermal budget was proposed to fabricate Ti02/Si02 Si MOSFETs with the gate lengths of 1, 3, 5, 10, 100 and 200 /lm. The capacitance-voltage characteristics were well behaved. The capacitive effective thickness (CET) of Ti02/SiOz gate stacked film was about 30-35 nm and its dielectric constant was ~ 14. Negative fixed oxide charges of 1.2x 1all cm-z, the frequency dispersion, and hysteresis were observed. The interface trap density (Dit) was about 1.1xl011 cm-2eV-! near midgap. The breakdown field. was 8 MV/cm. For the transistor performance, the short-channel effects were found. Since PMOS process flow with reduced thermal budget was introduced, the oxide quality found in TiOzlSiOz PMOS tra.l.'1sistors have approximately the same quality as that in TiOz/SiOz capacitors. The TiOz/Si02 gate stack structure was also proposed in 4H-SiC MOS capacitors. L11 this study, the oxidation temperature of evaporated titanium films was varied. From the experiment, the oxidation temperature of 800 °C provided good electrical characteristics. It gave CET of 17 TIm. The negative oxide trap charges were 2.87xl012 q(C/cmz) ai1.d interface trapped densities were 2-3x 012 cm-2 eyl at Ec-ET = 0-0.32 eV. The current density at gate voltage of 1 V was 2.4 X10-6 Ncmz. The use of SiOz films as an interfacial layer helps to improve leakage current of devices.
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Mulfinger, G. Robert. "Investigation of induced charge damage on self-aligned metal-gate MOS devices /." Online version of thesis, 2006. http://hdl.handle.net/1850/2036.
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Bensaid, Nacer-Eddine. "Use of phonon echoes in the study of II-VI compounds and dielectric Biâ†1â†2GeOâ†2â†0:Cr." Thesis, Lancaster University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293208.
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Fan, Xudong. "Cavity-QED studies of composite semiconductor nanostructure and dielectric microsphere systems /." view abstract or download file of text, 2000. http://wwwlib.umi.com/cr/uoregon/fullcit?p9998030.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--University of Oregon, 2000.Includes reprints of articles previously published by the author. Typescript. Includes vita and abstract. Includes bibliographical references (leaves 184-190). Also available for download via the World Wide Web; free to University of Oregon users.
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Lee, Ethan S. "Dielectric reliability in GaN metal-insulator-semiconductor high electron mobility transistors." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120368.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 73-74).
GaN Metal Insulator Semiconductor High Electron Mobility Transistors (GaN MIS-HEMTs) show excellent promise as high voltage power transistors that can operate efficiently at high temperatures and frequencies. However, current GaN technology faces several obstacles, one of which is Time-Dependent Dielectric Breakdown (TDDB) of the gate dielectric. Under prolonged electrical stress, the gate dielectric suffers a catastrophic breakdown that renders the transistor useless. Understanding the physics behind gate dielectric breakdown and accurately estimating the average time to failure of the dielectric are of critical importance. TDDB is conventionally studied under DC conditions. However, as actual device operation in power circuits involves rapid switching between on and off states, it is important to determine if estimations done from DC stress results are accurate. Due to the rich dynamics of the GaN MIS-HEMT system such as electron trapping and carrier accumulation at the dielectric/AlGaN interface, unaccounted physics might be introduced under AC stress that may cause error in DC estimation. To this end, we characterize TDDB behavior of GaN MIS-HEMTs at both DC stress conditions and more accurate AC stress conditions. We find that TDDB behavior is improved for AC stress compared to DC stress conditions at high stress frequencies. At 100 kHz, the average dielectric breakdown time is twice the average dielectric breakdown time under DC stress conditions. Furthermore, the impact of tensile mechanical stress on TDDB under DC stress is investigated. This is an important concern because of the piezoelectric nature of GaN and the substantial lattice mismatch between Si, GaN and AlGaN that results in high mechanical strain in the active portion of the device. If mechanical stress significantly impacts TDDB, designers will have to work with further constraints to ensure minimal stress across the dielectric. To address this, we have carried out measurements of TDDB under [epsilon] = 0.29% tensile strain. We find that TDDB in both the On-state and Off-state stress conditions are unaffected by this mechanical stress. Through measurements done in this thesis, we gather further insight towards understanding the physics behind TDDB. Through AC stress we find that the dynamics of the GaN MIS-HEMTs prolong dielectric breakdown times. Through mechanical stress we find that modulation of the 2-Dimensional Electron Gas and dielectric bond straining have minimal impact on TDDB.
by Ethan S. Lee.
S.M.
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Reynolds, Bryan. "Electronic Transport Properties of Nanonstructured Semiconductors: Temperature Dependence and Size Effects." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1463130513.
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48
Jeon, Yongjoo. "High-k gate dielectric for 100 nm MOSFET application /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004296.
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Wang, Chunlai. "AZADIPYRROMETHENE-BASED N-TYPE ORGANIC SEMICONDUCTORS AND HIGH DIELECTRIC CONSTANT POLYMERS FOR ELECTRONIC APPLICATIONS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case156708229609051.
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50
Granados-Alpizar, Bernal. "Nucleation and Growth of Dielectric Films on III-V Semiconductors During Atomic Layer Deposition." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/265341.
Повний текст джерелаАнотація:
In order to continue with metal-oxide-semiconductors (CMOS) transistor scaling and to reduce the power density, the channel should be replaced with a material having a higher electron mobility, such as a III-V semiconductor. However, the integration of III-V's is a challenge because these materials oxidize rapidly when exposed to air and the native oxide produced is characterized by a high density of defects. Deposition of high-k materials on III-V semiconductors using Atomic Layer Deposition (ALD) reduces the thickness of these oxides, improving the semiconductor/oxide interface quality and the transistor electrical characteristics. In this work, ALD is used to deposit two dielectrics, Al₂O₃ and TiO₂, on two III-V materials, GaAs and InGaAs, and in-situ X-ray photoelectron spectroscopy (XPS) and in-situ thermal programmed desorption (TPD) are used for interface characterization. Hydrofluoric acid (HF) etching of GaAs(100) and brief reoxidation in air produces a 9.0 ± 1.6 Å-thick oxide overlayer containing 86% As oxides. The oxides are removed by 1 s pulses of trimethylaluminum (TMA) or TiCl₄. TMA removes the oxide overlayer while depositing a 7.5 ± 1.6 Å thick aluminum oxide. The reaction follows a ligand exchange mechanism producing nonvolatile Al-O species that remain on the surface. TiCl₄ exposure removes the oxide overlayer in the temperature range 89°C to 300°C, depositing approximately 0.04 monolayer of titanium oxide for deposition temperatures from 89°C to 135°C, but no titanium oxide is present from 170°C to 230°C. TiCl₄ forms a volatile oxychloride product and removes O from the surface while leaving Cl atoms adsorbed to an elemental As layer, chemically passivating the surface. The native oxide of In(0.53)Ga(0.47)As(100) is removed using liquid HF and gas phase HF before deposition of Al₂O₃ using TMA and H₂O at 170°C. An aluminium oxide film with a thickness of 7.2 ± 1.2 Å and 7.3 ± 1.2 Å is deposited during the first pulse of TMA on liquid and gas phase HF treated samples, respectively. After three complete ALD cycles the thickness of the aluminum oxide film is 10.0 ± 1.2 Å on liquid HF treated and 6.6 ± 1.2 Å on gas phase HF treated surfaces. Samples treated with gas phase HF inhibit growth. Inhibition is caused by residual F atoms that passivate the surface and by surface poisoning due to the thicker carbon film deposited during the first pulse of TMA. On InGaAs covered by native oxide, the first TMA pulse deposits 9 Å of aluminum oxide, and reaches saturation at 13 Å after 15 pulses of TMA. The film grows by scavenging oxygen from the substrate oxides. Substrate oxides are reduced by the first pulse of TMA even at 0°C. At 0°C, on a 9 Å thick Ga-rich oxide surface, 1 pulse of TMA mainly physisorbs and a limited amount of aluminum oxide is deposited. At 0°C, 110°C, and 170°C, more aluminum oxide is deposited on surfaces initially containing As oxide, and larger binding energy (BE) shifts of the O 1s peak are observed compared to surfaces that contain Ga oxides only, showing that As oxides improve the nucleation of Al₂O₃.