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Deep level transient spectroscopy of heteroepitaxial polycrystalline diamond and aluminum nitrideKarbasi, Hossein, January 1998 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 107-111). Also available on the Internet.
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A study of electroluminescence produced by A1GaN/GaN high electron mobility transistors. /Sarault, Keith Richard. January 1900 (has links)
Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 77-78). Also available in electronic format on the Internet.
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Aluminum nitride deposition / characterization & pMEMS / saw device simulation / fabricationPagán, Vincent Richard. January 1900 (has links)
Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xvii, 169 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 147-155).
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Deposi??o de A/N por sputtering n?o reativoDamasceno, Eduardo Moreira 27 January 2011 (has links)
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Previous issue date: 2011-01-27 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work we deposit via non-reactive magnetron sputtering of radio-frequency nanofilmes
of nitreto of aluminum(AlN). The nanofilms aluminum nitride are semiconductors materials
with high thermal conductivity, high melting point, piezoelectricity and wide band gap (6,
2 eV) with hexagonal wurtzite crystal structure, belonging to the group of new materials called
III-V nitrides in which together with the gallium nitride and indium nitride have attracted much
interest because they have physical and chemical properties relevant to new technological applications,
mainly in microelectronic and optoelectronic devices. Three groups were deposited
with thicknesses nanofilms time dependent on two substrates (glass and silicon) at a temperature
of 25 ? C. The nanofilms AlN were characterized using three techniques, X-ray diffraction,
Raman spectroscopy and atomic force microscopy (AFM), examined the morphology of these.
Through the analysis of X-rays get the thickness of each sample with its corresponding deposition
rate. The analysis of X-rays also revealed that nanofilms are not crystalline, showing
the amorphous character of the samples. The results obtained by the technique, atomic force
microscopy (AFM) agree with those obtained using the technique of X-rays. Characterization
by Raman spectroscopy revealed the existence of active modes characteristic of AlN in the
samples / Neste trabalho depositamos via magnetron sputtering de r?dio-frequ?ncia n?o reativo nanofilmes
de nitreto de alum?nio (AlN). Os nanofilmes de nitreto de alum?nio s?o materiais semicondutores
com alta condutividade t?rmica, elevado ponto de fus?o, piezoeletricidade e largo
"bandgap"(6;2 eV) com estrutura cristalina wurtz?tica hexagonal, pertencentes ao grupo de novos
materiais denominados nitretos III-V que em conjunto com o nitreto de g?lio e o nitreto
de ?ndio t?m despertado muito interesse por possu?rem propriedades f?sico-qu?micas relevantes
para novas aplica??es tecnol?gicas, principalmente em microeletr?nica e dispositivos optoeletr?nicos.
Foram depositados tr?s grupos de nanofilmes com as espessuras depend?ntes do
tempo, sobre dois tipos de substratos (vidro e sil?cio) a uma temperatura de 25?C. Os nanofilmes
de AlN foram caracterizados usando tr?s t?cnicas, a difra??o de raios-X, espectroscopia Raman
e microscopia de for?a at?mica (AFM), analisado-se a morfologia desses. Atrav?s da an?lise
dos raios-X obtemos a espessura de cada amostra com sua respectiva taxa de deposi??o. A an?lise
dos raios-X tamb?m revelou que os nanofilmes n?o s?o cristalinos, evidenciando o car?ter
amorfo das amostras. Os resultados obtidos atrav?s da t?cnica, microscopia de for?a at?mica
(AFM) concordam com os obtidos usando a t?cnica de raios-X. A caracteriza??o por espectroscopia
Raman evidenciou a exist?ncia de modos ativos caracter?sticos do AlN nas amostras
analisadas
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Produção e caracterização de filmes de nitreto de alumínio e sua aplicação em guias de onda tipo pedestal. / Fabrication and characterization of aluminum nitride films and its application in pedestal-type optical waveguides.Maria Elisia Armas Alvarado 28 April 2017 (has links)
O presente trabalho tem como objetivo principal a produção e estudo de filmes de nitreto de alumínio (AlN) depositados por pulverização catódica (sputtering) reativa e a fabricação e caracterização de guias de onda tipo pedestal utilizando o AlN como núcleo. Inicialmente, filmes de AlN foram fabricados por pulverização catódica reativa (sputtering) de rádio frequência (RF) utilizando um alvo de alumínio (Al) com 99,999% de pureza, e nitrogênio (N2) como gás reativo. Subsequentemente, os filmes foram caracterizados mediante as técnicas de elipsometria, difração de raios X (DRX), espectroscopia de absorção por transformada de fourier na região do infravermelho (FTIR) e espectroscopia de absorção na região do ultravioleta e do visível (UV-VIS). Tendo as melhores condições ópticas e físicas para a deposição de filmes de AlN, foram fabricados neste trabalho guias de onda tipo pedestal utilizando estes filmes como núcleo. O guia de onda pedestal traz um processo de fabricação alternativo, em que a geometria do guia de onda determina-se na camada anterior ao do núcleo, assim já não é necessário delinear as paredes laterais da camada de núcleo facilitando desta forma, o processo de fabricação do dispositivo. Os guias de tipo pedestal fabricados neste trabalho foram definidos através da corrosão parcial do óxido de silício (SiO2) mediante a técnica de RIE (Reactive Ion Etching) usando gases trifluorometano (CHF3) e oxigênio (O2) como gases reativos. Uma vez definido o pedestal, um filme de nitreto de alumínio é depositado sobre o SiO2 com a finalidade de constituir o núcleo do guia de onda. O ar foi utilizado como revestimento superior, cujo índice de refração (n = 1) aumenta o confinamento da luz no núcleo e também para poder possibilitar a caracterização das perdas ópticas do dispositivo. Para esta caracterização usamos a técnica de vista superior que permitiu a análises das perdas ópticas de propagação para diferentes alturas de pedestal e diferentes espessuras de núcleo tanto para filmes de AlN orientado no plano cristalino (002) quanto para filmes de AlN amorfos. / The main objective of this work is the production and study of Aluminum Nitride (AlN) films deposited by reactive sputtering and the fabrication and characterization of pedestal optical waveguides using AlN as core. Initially, aluminum nitride films were produced by reactive sputtering using a 99.999% aluminum (Al) purity target, and nitrogen (N2) as the reactive gas. Subsequently, the films were characterized by ellipsometry, X-ray Diffraction, Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet-visible spectroscopy (UV-VIS). Once the best optical and physical conditions for the deposition of AlN films were obtained, pedestal waveguides using these films as a nucleus were fabricated in this work. The pedestal waveguide provides an alternative manufacturing process where the geometry of the waveguide is determined in the pre-core layer, so it is no longer necessary to delineate the side walls of the core layer thereby facilitating the device fabrication process. The pedestal waveguides fabricated in this work were defined by the partial corrosion of SiO2 by the RIE (Reactive Ion Etching) technique using CHF3 and O2 gases as reactive gases. Once the pedestal is completed, an aluminum nitride film is deposited onto the SiO2 layer as the waveguide core. The air was used as an upper cladding, whose refractive index (n ? 1) increases the confinement of the light in the core and also allows the optical loss characterization. For this characterization, we used the superior view technique that allowed the analysis of optical propagation losses for different pedestal heights and different core thicknesses for both highly (002) oriented and amorphous AlN films.
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Synthesis of thin piezoelectric ALN films in view of sensors and telecom applications = Síntese de filmes finos de ALN piezoelétrico para aplicações em sensores e dispositivos de alta frequência / Síntese de filmes finos de AlN piezoelétrico para aplicações em sensores e dispositivos de alta frequênciaMoreira, Milena de Albuquerque, 1977- 26 August 2018 (has links)
Orientador: Ioshiaki Doi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-26T04:10:17Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: Os requisitos do mercado consumidor de dispositivos de alta frequência têm sido cada vez mais exigentes nas últimas décadas. Assim, é necessária uma melhoria contínua no desempenho dos dispositivos a fim de atender a estes requisitos. Numa visão macro, alterações no desenho dos dispositivos podem resultar em melhoria de desempenho. Em uma visão micro, as propriedades físicas dos materiais que compõem os dispositivos têm uma forte influência no desempenho final dos mesmos. No caso de dispositivos de alta frequência baseados em materiais piezoelétricos, uma forma natural de melhorar o seu desempenho é através da melhoria das propriedades da camada piezoelétrica. O material piezoelétrico estudado neste trabalho é o Nitreto de Alumínio (AlN), o qual destaca-se entre outros materiais piezoelétricos devido à sua combinação única de propriedades. Esta tese apresenta o resultado de estudos experimentais na síntese de filmes finos de AlN tendo em vista aplicações em altas frequências, microeletrônica e sensores. O principal objetivo desta tese é a melhoria nas propriedades funcionais do AlN para melhor atender aos requisitos das aplicações em questão. Isto é obtido através do controle cuidadoso da estrutura, textura cristalográfica e composição do filme. As propriedades piezoelétricas dos filmes de AlN foram melhoradas através da dopagem dos filmes com Sc. Amostras com diferentes concentrações de Sc foram fabricadas e analisadas, e o valor do coeficiente de acoplamento eletromagnético (kt2) foi duplicado ao adicionar 15 % de Sc aos filmes de AlN. O aumento no valor de kt2 é desejável uma vez que pode diminuir as restrições no projeto de dispositivos de alta frequência. Neste trabalho é proposta também uma nova configuração experimental com o objetivo de obter um melhor controle na deposição de filmes de AlN inclinados no eixo-c. Filmes com uniformidade em espessura e inclinação foram obtidos ao utilizar-se a referida configuração experimental. Filmes com tais características são aplicáveis em sensores baseados em dispositivos eletroacústicos operando em meio líquido/viscoso. Foram também realizados estudos com o objetivo de obter filmes de AlN orientados no eixo-c e depositados diretamente sobre substratos de Si e a temperaturas reduzidas. A técnica de deposição utilizada foi HiPIMS e os resultados indicam melhorias significativas na textura dos filmes quando comparados com o processo de deposição convencional por corrente-direta pulsada / Abstract: The requirements of the consumer market on high frequency devices have been more and more demanding over the last decades. Thus, a continuing enhancement of the devices¿ performance is required in order to meet these demands. In a macro view, changing the design of the device can result in an improvement of its performance. In a micro view, the physical properties of the device materials have a strong influence on its final performance. In the case of high frequency devices based on piezoelectric materials, a natural way to improve their performance is through the improvement of the properties of the piezoelectric layer. The piezoelectric material studied in this work is AlN, which is an outstanding material among other piezoelectric materials due to its unique combination of material properties. This thesis presents results from experimental studies on the synthesis of AlN thin films in view of telecom, microelectronic and sensor applications. The main objective of the thesis is to custom design the functional properties of AlN to best suit these for the specific application in mind. This is achieved through careful control of the crystallographic structure and texture as well as film composition. The piezoelectric properties of AlN films were enhanced by doping with Sc. Films with different Sc concentrations were fabricated and analyzed, and the coupling coefficient (kt2) was enhanced a factor of two by adding 15 % of Sc to the AlN films. The enhancement of kt2 is of interest since it can contribute to a more relaxed design of high frequency devices. Further, in order to obtain better deposition control of c-axis tilted AlN films, a new experimental setup were proposed. When this novel setup was used, films with well-defined thicknesses and tilt uniformity were achieved. Films with such characteristics are very favorable to use in sensors based on electroacoustic devices operating in viscous media. Studies were also performed in order to obtain c-axis oriented AlN films deposited directly on Si substrates at reduced temperatures. The deposition technique used was HiPIMS, and the results indicated significant improvements in the film texture when comparing to the conventional Pulsed DC deposition process / Doutorado / Eletrônica, Microeletrônica e Optoeletrônica / Doutora em Engenharia Elétrica
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Sublimation growth of ALN bulk crystals and high-speed CVD growth of SiC epilayers, and their characterizationLu, Peng January 1900 (has links)
Doctor of Philosophy / Department of Chemical Engineering / James H. Edgar / The effects of process conditions on the material’s properties were investigated for the sublimation growth of aluminum nitride and the epitaxial growth of silicon carbide. Since the mid 1990’s, these semiconductors have made new types of high power electronics and short wavelength optoelectronics that were never before feasible.
The sublimation growth of AlN crystals on SiC seeds was carried out to produce high quality AlN bulk crystals. Si-face, 3.5 º off-axis 6H-SiC (0001) and 8 º off-axis 4H-SiC (0001) wafers were used as the substrates. An investigation of the initial growth demonstrated 1800 – 1850ºC was the optimum temperature for AlN growth. By optimizing the temperature gradient, large area AlN layer was deposited. Consecutive growths and continuous growth were performed to enlarge the crystal thickness. Single-crystalline AlN layers, each with a thickness of 2 mm and a diameter of 20 mm, were produced. X-ray diffraction confirmed the grown AlN had good crystal quality. Approximately 3 – 6 at% of Si and 5 – 8 at% of C were detected in the crystals by x-ray photoelectron spectroscopy, which came from the decomposition of SiC seeds and the degradation of the graphite components in the furnace. Molten KOH/NaOH etching revealed the dislocation density decreased from 108 cm-2 to 106 cm-2 as the AlN layer thickness increased from 30 μm to 2 mm.
Epitaxial growth of SiC was carried out in a chemical vapor deposition system. High-quality 6H-SiC and 4H-SiC homoepitaxial films were produced at growth rates up to 80 μm/hr by using a novel single precursor, methyltrichlorosilane (MTS). Inclusions of 3C-SiC were circumvented by employing 8º mis-orientated substrates. Adjusting the H2/Ar flow ratio in the carrier gas effectively changed the C/Si ratio in the gas phase due to the reaction between H2 and the graphite heater; thereby, influencing surface roughness and dislocation density. Low H2/Ar ratios of 0.1 and 0.125 produced smooth surfaces without step-bunching. Higher H2/Ar ratios of 0.2 and 0.33 enhanced the conversion of basal plane dislocations into threading edge dislocations, and reduced the density of basal plane dislocations to approximately 600 cm-2.
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Depozice Al a AlN ultratenkých vrstev na křemíkový a grafenový substrát / The deposition of Al and AlN ultrathin layers on silicon and graphene substrateŘihák, Radek January 2016 (has links)
This master's thesis deals with preparation and analysis of ultrathin films of aluminum and aluminum nitride. Films were prepared by effusion cells designed in previous bachelor's thesis. Cell construction and testing is included in this thesis. Behavior of aluminum on silicon dioxide, silicon and graphene was studied. Preparation of aluminum nitride by effusion cell and nitrogen ion source is described.
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Strain-Controlled AlN Growth on SiC Substrates / SiC基板上への歪み制御AlN層の成長Kaneko, Mitsuaki 23 September 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19997号 / 工博第4241号 / 新制||工||1656(附属図書館) / 33093 / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 木本 恒暢, 教授 藤田 静雄, 准教授 船戸 充 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
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Aluminum Nitride Waveguides for Potential Soliton Propagation.Santamaria Hernandez, Amilcar 27 May 2016 (has links)
No description available.
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