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An interactive picture manipulation system.Franklin, Daniel Lewis January 1978 (has links)
Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / M.S.
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Digital scaling of binary imagesUlichney, Robert January 1979 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Robert A. Ulichney. / M.S.
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Aplicabilidade da bateria neurocognitiva computadorizada da Universidade da Pensilvânia em adultos com transtorno bipolar / Applicability of computerized neurocognitive battery of University of Pennsylvania in adults with bipolar disorderAzevedo, Erika Bispo de 24 October 2017 (has links)
Introdução: O desempenho neurocognitivo é considerado como potencial endofenótipo do transtorno bipolar. As baterias de avaliação totalmente informatizadas representam uma alternativa interessante aos testes neuropsicológicos tradicionais porque oferecem vantagens como correção e armazenagem automatizada dos dados, redução do tempo de aplicação e diminuição da interferência subjetiva do aplicador. No Brasil ainda é raro o número de baterias totalmente computadorizadas disponíveis para uso em pesquisa, portanto, o objetivo deste trabalho foi verificar a aplicabilidade da Bateria Computadorizada da Universidade da Pensilvânia em uma amostra de adultos com Transtorno Bipolar. Métodos: Avaliamos o desempenho da Bateria Neurocognitiva Computadorizada da Universidade da Pensilvânia contra uma Bateria Neurocognitiva Tradicional em uma amostra de 30 pacientes com Transtorno Bipolar eutímicos versus 27 controles saudáveis pareados por idade, gênero e educação parental. Resultados: Os pacientes apresentaram desempenho pior do que controles saudáveis no controle inibitório/controle executivo, velocidade de processamento e tarefas de aprendizagem visuoespacial da Bateria Neurocognitiva Tradicional, enquanto que nenhuma diferença significativa foi observada com a Bateria Neurocognitiva Computadorizada da Universidade da Pensilvânia. Dentro do grupo de pacientes, os sintomas afetivos subclínicos se correlacionaram inversamente com a flexibilidade mental na Bateria Neurocgnitiva Tradicional e, com a memória operacional e o raciocínio visuoespacial na Bateria Neurocognitiva Computadorizada da Universidade da Pensilvânia. Paralelamente, os desempenhos dessas tarefas estão diretamente correlacionados com o funcionamento sócio-ocupacional. Limitações: O tamanho modesto da amostra e o fato de que estudamos um grupo misto de pacientes com Transtorno Bipolar tipo I e tipo II podem ter aumentado o risco de erros estatísticos de tipo II. Conclusões: Os resultados desta investigação preliminar sugerem que os testes tradicionais com uma bateria neuropsicológica abrangente proporcionam maior sensibilidade para detectar diferenças entre grupos. No entanto, as tarefas da Bateria Neurocognitiva Computadorizada da Universidade da Pensilvânia correlacionaram-se com variáveis clínicas específicas no grupo de pacientes, fornecendo informações adicionais relevantes que não foram detectadas com a Bateria Neurocognitiva Tradicional. Assim, a seleção de testes adequada dependeria das funções cognitivas específicas que se pretende analisar e da questão sob investigação / Background: Neurocognitive performance is considered a potential endophenotype of bipolar disorder (BD) and fully computerized batteries represent an interesting alternative to traditional neuropsychological testing because they offer advantages such as automated correction and storage of data, reduction of application time and decrease of the applicator\'s subjective interference. In Brazil, the number of fully computerized batteries available for research use is still rare, so the purpose of this study was to verify the applicability of the Computerized Neurocognitive Battery of the University of Pennsylvania in a sample of adults with Bipolar Disorder. Methods: We assessed the performance of the Computerized Neurocognitive Battery of the University of Pennsylvania against a Traditional Neurocognitve Battery in a sample of 30 euthymic bipolar disorder patients versus 27 healthy controls matched for age, gender and parental education. Results: The patients performed worse than healthy controls in executive control/ response inhibition, processing speed and visuospatial learning tasks of the Traditional Neurocognitve Battery, while no significant differences were observed with the Computerized Neurocognitive Battery of the University of Pennsylvania. Within the Bipolar Disorder group, subclinical affective symptoms inversely correlated with mental flexibility in the Traditional Neurocognitve Battery, and with working memory and visuospatial reasoning in the Computerized Neurocognitive Battery of the University of Pennsylvania. Concurrently, performances on these tasks directly correlated with social/ occupational functioning. Limitations: The modest sample size and the fact that we studied a mixed group of patients with type I and type II Bipolar Disorder might have increased the risk of type II statistical errors. Conclusions: The results of this preliminary investigation suggest that traditional testing with a comprehensive neuropsychological battery affords better sensitivity to detect between-group differences. Nevertheless, Computerized Neurocognitive Battery of the University of Pennsylvania tasks correlated with specific clinical variables in the Bipolar Disorder group, providing relevant additional information that was not detected with the Traditional Neurocognitve Battery. Thus, adequate test selection would depend on the specific neurocognitive functions to be analyzed and the question under investigation
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Avaliação da acurácia e precisão de um instrumento de medição do consumo alimentar de escolares do município de Salesópolis - SP / Application of a computerized instrument for measuring food intake of school children of Salesópolis - SPRamos, Jamile Fernandes 24 October 2013 (has links)
Introdução. Muitos estudos epidemiológicos sugerem a potencial relação do consumo habitual de nutrientes ou alimentos com as doenças crônicas não transmissíveis (DCNT). Os efeitos da dieta na saúde humana não ocorrem em curto prazo e sim pela exposição repetida em períodos de tempo maior. O interesse em se estudar o consumo alimentar na fase da adolescência justifica-se pela associação de hábitos alimentares inadequados neste grupo etário serem um fator de risco para enfermidades, particularmente as de origem metabólica. A avaliação e a quantificação da dieta habitual dos indivíduos e escolha do instrumento para a mensuração do consumo são exercícios difíceis, pois ambos influenciam a plausibilidade dos resultados obtidos. Cada vez mais os sistemas computadorizados e o meio digital estão sendo incrementados no campo das pesquisas relacionadas à saúde da população, pois permitem recolher dados de forma contínua, independentemente da hora do dia e do dia da semana, e sem limitações geográficas. Objetivo. Aplicar o Questionário de Frequência Alimentar Simplificado para Adolescentes (QFASA) em ambiente digital para avaliação da dieta habitual de escolares do município de Salesópolis SP. Métodos. Uma amostra de 157 escolares respondeu a dois Questionários de Frequência Alimentar Simplificado para Adolescentes versão virtual (QFASA) e três Recordatórios de 24 horas (R24h). O QFASA possui 58 itens alimentares, semi-quantitativo e com frequência de consumo. Foi realizada a descrição do consumo habitual dos escolares pelo QFASA e pelo R24h. Os resultados de consumo alimentar de macronutrientes e alguns micronutrientes foram comparados entre: QFASA aplicado no primeiro momento (QFASA1) x QFASA aplicado segundo momento (QFASA2) e QFASA2 x média entre 3 R24h. Resultados. De 157 adolescentes, com idade média de 13 anos, 64 por cento eram do sexo feminino. Os meninos apresentaram consumo superior de energia e nutrientes comparado com as meninas na média dos 3 Recordatórios de 24 horas e no 7 QFASA2. Ao comparar os dois QFASA observou-se diferença entre as médias de consumo dos macro e micronutrientes, com exceção da vitamina C e o QFASA1 apresentou valores superiores para todos os nutrientes estudados. Quando confrontados os valores de consumo do QFASA2 com o R24h, observa-se também diferenças entre suas médias, com exceção do colesterol e vitamina C para o sexo masculino, além disso o QFASA2 superestima todos os nutrientes estudados. Conclusão. Os meninos apresentam uma média maior de consumo alimentar quando comprados as meninas para a maioria dos nutrientes estudados, tanto no R24h quanto no QFASA. O QFASA na sua versão virtual não pode ser considerado um bom instrumento para avaliar o consumo habitual dos adolescentes, pois apresenta médias significativamente diferentes, quando comparado ao R24h (método de referência). Além disso, mostrou-se de difícil compreensão pelos adolescentes, necessitando de uma revisão dos seus itens, porções definidas e frequência de consumo e posterior estudo de usabilidade e Teste de Resposta ao Item. / Introduction. Many epidemiological studies have demonstrated the potential relationship between habitual intake of nutrients or foods with chronic non communicable diseases (NCDs). Due to the effects of diet on human health do not occur in the short term but by repeated periods of a long time. The interest in studying adolescents food intake is justified by the association of poor dietary habits in this group being a risk factor for diseases, particularly those of metabolic origin. The assessment,quantification and choice of an instrument for measuring intake of adolescents usual diet are difficult exercises because both influence the plausibility of the results. Increasingly, computer systems and digital media are being incremented in the field of research related to the health of the population, they allow to collect data continuously, regardless of time of day and day of the week, and without geographical limitations. Objective. Applying the Simplified Food Frequency Questionnaire for Adolescents (SFQA) in digital environment to evaluation of usual diet of school children in Salesópolis - SP. Methods. A sample of 157 students answered two Simplified Food Frequency Questionnaire for Adolescents - virtual version (SFQA) and three 24-hour recalls (24h). The SFQA had 58 semi-quantitative food items with the frequency of consumption. The description of the usual diet of students by QFASA and the 24h was performed. The results of dietary intake of macronutrients and some micronutrients were compared in two moments: 1. SFQA - applied at first time (SFQA1) x SFQA - applied second time; 2. The average of (SFQA2) between 3 R24h x SFQA2. Results. Between 157 adolescents, mean age of 13 years (64 per cent female). The boys had higher intake of energy and nutrients when compared to girls in the average of three 24-hour recalls and SFQA2. When comparing the two SFQA was observed difference between the mean intake of macronutrients and micronutrientes, with the exception of vitamin C and SFQA1 revealed higher values in all the studied nutrients. When confronted 9 intake values of SFQA2 with 24h, was observed differences between their averages, with the exception of cholesterol and vitamin C for males, moreover the SFQA2 over-estimated all studied nutrients. Conclusion. Boys have higher food intake than girls in most nutrients studied, in the R24h and SFQA. The SFQA in its virtual version can not be considered a good instrument to assess the habitual intake of adolescents, has been shown significantly differences between means when compared to R24h (reference method). Moreover, proved elusive for adolescents, requiring a revision of their items, defined portions and frequency of intake and subsequent usability study and test item response.
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Espectropolarimetro computadorizado : nova maneira de obtenção da atividade ótica / Computerized spectrometer: a new way to obtain optical activity dataMelo, Washington Luiz de Barros 23 May 1985 (has links)
Montamos um espectrômetro o qual nos permite obter dados de atividade ótica Dispersão Rotatória (DRO) e Dicroísmo Circular (DC) simultaneamente. O sistema ótico consiste de uma fonte de luz, um monocromador, um suporte para amostra, um analisador gigante e um detector de luz. O analisador girante é sustentado por um mancal pneumático e gira usando um motor de passo, o qual é controlado por um microcomputador. Um outro motor de passo também controlado por microcomputador é usado para girar a grade de difração do monocromador. Para obter os espectros de DRO e DC, o monocromador pára em um certo comprimento de onda, enquanto o eixo de transmissão do analisador é posicionado em β= 0°, 45°, 90° e -45° relativo ao eixo de transmissão do polarizador. O microcomputador através do detector de luz lê as quatro intensidades de luz e usando um formalismo desenvolvido por nós, relaciona-as à elipticidade e a rotação ótica naquele comprimento de onda. O monocromador é então girado a um novo comprimento de onda e o procedimento é repetido. No final, os espectros de DC e DRO podem ser mostrados em uma Tabela ou com um Gráfico. Além de funcionar como um espectropolarímetro, o equipamento pode ser usado também como um espectrofotômetro, para acompanhar cinética de reação, para medir dicroísmo linear, etc... Devido à relação sinal/ruído, temos nos ângulos medidos, uma resolução de 1º / We have assembled a spectrometer which provides the optical activity data Optical Rotatory Dispersion (ORD) and Circular Dichroism (CD) simultaneously. The Optical System consists of a source of light, a monochromator, a polarizer, a sample holder, a rotating analyzer and a light detector. The rotating analyzer is supported by a pneumatic bearing and rotates using a step motor which is controlled by a microcomputer. Another spet motor also controlled by the microcomputer is used to rotate the diffraction grating of the monochromator. To obtain the ORD and CD spectra, the monochromator stops at a certain wave length, while the transmission axis of the analyzer is positioned at β= 0°, 45°, 90° e -45° relative to the transmission axis of the polarizer. The microcomputer through the light detector reads the four light intensities and using the formalism developed by us relates them to the elipticity and optical rotation at that wavelength. The monochromator is then rotated to a new wavelength and the procedure is repeated. At the end the CD and ORD spectra can be shown in a Table or as a graph. Besides functioning as a spectropolarimeter, the equipment can be use also as a regular spectrometer, to follow kinetic of recreations, to measure linear dichroism, etc Due to the signal/noise ratio we have in the measured angles a resolution of 1°
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Planejamento computacional tri-dimensional para radioterapia em região pélvica de animais selvagens / 3D Computacional planning for radiotherapy in pelvic region of wild animalsSilva, Diego de Andrade 20 December 2018 (has links)
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Previous issue date: 2018-12-20 / Neste trabalho foi estudado a implementação de um sistema de planejamento radioterápico empregado na rotina da medicina humana para adequação e uso na oncologia veterinária de animais selvagens. Foram ilustrados os conceitos básicos sobre radioterapia, suas indicações clínicas, técnicas de tratamento, características dos equipamentos e fontes de radiação empregados. O avanço tecnológico, principalmente na área da ciência da computação, proporcionou o desenvolvimento de software com linguagem exequível, mais eficiente e dedicado para as diversas áreas das atividades humanas. A medicina tem se beneficiado destas tecnologias, sendo a radioterapia a modalidade médica que tem se revolucionado constantemente com a oferta de sistemas computacionais tri-dimensionais para planejamentos de tratamento (TPS), proporcionando maior segurança na liberação da dose de radiação no volume alvo, melhorando a resposta terapêutica e minimizando os efeitos radiobiológicos indesejados da técnica. Foi utilizado um TPS aplicado em clínica de radioterapia humana e adequado os parâmetros radiométricos, clínicos e anatômicos para a viabilidade do uso deste TPS na radioterapia veterinária. Para a realização dos planejamentos radioterápicos dos animais estudados foram usadas imagens tomográficas da região pélvica de animais selvagens assistidos pela FMVZ. Foram propostos protocolos para a implantação dos planejamentos computacionais em veterinária mediante a análise da homogeneidade da distribuição de dose de radiação no volume de tratamento planejado (PTV) e a garantia da proteção dos órgãos circunvizinhos ao PTV. / The research focus was to test the viability of applying radiotherapeutic planning commonly used in human medical science in veterinary oncology for wild animals. The basic concepts of radiotherapy as well as clinical indications, treatment techniques, tools features and radiation sources were evidenced in the study. Technological development, especially in computer science, has provided a more sophisticated software, with viable language resources and oriented for various areas of human activities. Such technologies have been excellent for medicine and radiology has been provided with modern systems, such as 3D computers for treatment planning (TPS). This type of equipment provides higher security when releasing radiation doses, improving the therapeutic response and reducing unwanted radiobiological effects. A human radiotherapy TPS was adapted to be viable on using it in veterinary radiotherapy, adjusting clinical and anatomical parameters. For the radiotherapy planning, wild animals assisted by FMVZ were analyzed and tomographic images of the animal’s pelvis were examined. Using the images, the suggested protocol was the implement of computational plans in veterinary through the radiation dose analysis for the planning treatment volume, securing organs surrounding the PTV.
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Reconstrução tridimensional de objetos a partir das projeções de suas secções / Tridimensional objects reconstruction from the projections of theirs sectionsMattos, Patrícia Noll de January 1996 (has links)
Este trabalho trata da reconstrução tomográfica bidimensional e tridimensional, a partir de projeções, visando sua utilização em qualquer aplicação que necessite do volume completo do objeto em questão ou que necessite das imagens adquiridas dos- objetos projetados. Propicie-se utilizar um dos métodos pelo qual a tomografia Computadorizada gera as fatias bidimensionais do corpo exposto, expandindo-o para a terceira dimensão. Para tornar isto possível, é necessário o estudo de métodos de reconstrução-bidimensional, bem como a implementação de um deles. E desenvolvido, então, um estudo sobre os conceitos da tomografia computadorizada, seus diferentes tipos, contendo, os métodos de reconstruçãobidimensional utilizado por elas, alem, dos métodos de aquisição das projeções dos objetos a serem reconstruídos. E apresentada uma proposta de trabalho bidimensional, onde será implementado, alem do algoritmo de reconstrução, o processo de aquisição das projeções do objeto em questão, bem como, a modelagem do mesmo. Além, do desenvolvimento de uma proposta de trabalho tridimensional, onde o método de reconstrução bidimensional desenvolvido será expandido para a terceira dimensão e implementado, juntamente com o processo de aquisição dos objetos tridimensionais projetados, bem como, a modelagem dos mesmos. Um protótipo para cada uma destas propostas é gerado, contendo, cada um, a etapa de aquisição das imagens projetadas, e a etapa de reconstrução do objeto. Tanto os resultados da imagem sendo reconstruída, como as imagens adquiridas dos objetos projetados, são Bravados em arquivos. Por fim, é apresentada uma analise dos resultados gerados por estes protótipos, no que diz respeito a convergência de seus algoritmos, e a melhor maneira de utilizá-los, a fim de se obter um melhor resultado. / This paper is about bidimensional and tridimensional tomographic reconstruction working with projections in order to use in any application that needs complete volume of the object used or that needs images of the projected objects acquired. It is used one of the methods by which the computerized tomography generates bidimensional slices of the exposed body expanding it to third dimension. In order to make it possible it was necessary to study bidimensional reconstruction methods, as well as implementing one of them. It is developed a study on concepts of computerized tomography, its different types, including bidimensional reconstruction methods used by them, besides the methods used to acquire projections of the objects to be reconstructed. It is presented a proposal of the bidimensional work, where it will be implemented, besides the reconstruction algorithm, the aquisition process of the projection of the meant objects, as well as modelling them. It is also developed a proposal of a tridimensional work, where the bidimensional reconstruction method developed will be implemented and expanded to third dimension as well as the process of aquisition of the tridimensionals projected objects as well as modelling them. A prototype of these proposals is generated , containing each one the aquisition step of the projected images and the reconstruction step of the object. The results of the reconstructed image as well as the acquired images of the projected objects are saved in files. Finally it is presented an analysis of the generated results of the prototypes as to the convergence of these algorithms and the best way to use them in order to obtain a better result.
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Role of 18F FDG PET/CT as a novel non-invasive biomarker of inflammation in chronic obstructive pulmonary diseaseChoudhury, Gourab January 2018 (has links)
A characteristic feature of Chronic Obstructive Pulmonary Disease (COPD) is an abnormal inflammatory response in the lungs to inhaled particles or gases. The ability to assess and monitor this response in the lungs of COPD patients is important for understanding the pathogenic mechanisms, but also provides a measure of the activity of the disease. Disease activity is more likely to relate to lung inflammation rather than the degree of airflow limitation as measured by the FEV1. Preliminary studies have shown the 18F fluorodeoxyglucose positron emission tomography (18F FDG-PET) signal, as a measure of lung inflammation, is quantifiable in the lungs and is increased in COPD patients compared to controls. However, the methodology requires standardisation and any further enhancement of the methodology would improve its application to assess inflammation in the lungs. I investigated various methods of assessing FDG uptake in the lungs and assessed the reproducibility of these methods, and particularly evaluated whether the data was reproducible or not in the COPD patients (smokers and ex-smokers). This data was then compared with a group of healthy controls to assess the role of dynamic 18F FDG-PET scanning as a surrogate marker of lung inflammation. My data showed a good reproducibility of all methods of assessing FDG lung uptake. However, using conventional Patlak analysis, the uptake was not statistically different between COPD and the control group. Encouraging results in favour of COPD patients were nonetheless shown using compartmental methods of assessing the FDG lung uptake, suggesting the need to correct for the effect of air and blood (tissue fraction effect) when assessing this in a highly vascular organ like the lungs. A prospective study analysis involving a bigger cohort of COPD patients would be desirable to investigate this further.
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Clinician attitudes towards, and patient well-being outcomes from, computerised Cognitive Behavioural Therapy : a research portfolioPersson, Joanne K. January 2018 (has links)
This thesis follows the research portfolio format and is carried out in part fulfilment of the academic component of the Doctorate in Clinical Psychology at the University of Edinburgh. An abstract provides an overview of the entire portfolio thesis. Chapter One contains a systematic review of published research exploring staff attitudes towards computerized cognitive behavior therapy (cCBT). Chapter Two is an empirical study examining a range of potential predictor variables on well-being outcomes from cCBT. Chapter one is prepared for Behavioural and Cognitive Psychotherapy, whereas chapter two is prepared for submission to the journal, Behaviour Research and Therapy. Both chapters follow the relevant author guidelines. Background: Evidence suggests that computerised cognitive behavioural therapy (cCBT) is both effective and efficacious in treating depression and anxiety. Numerous barriers to its implementation and uptake have been identified, however, including attitudinal variables and high patient attrition rates. Research examining predictors of response from cCBT have tended to adopt the pathological model of distress, focussing on symptom reduction rather than the promotion of well-being. Furthermore, exploration of possible predictors has tended to focus on a narrow range of factors (e.g. age, gender), neglecting key psychosocial variables (e.g. social identification, baseline distress) that could be exerting an effect. Aims: A systematic review examined staff attitudes towards cCBT for depression, anxiety, and comorbid depression and anxiety, focussing on three attitudinal domains: Perceived acceptability of cCBT; staff's self-reported intention to use cCBT in the future, and perceived advantages and disadvantages of cCBT for depression and/or anxiety. An experimental study was subsequently conducted, examining a range of potential predictors on well-being outcomes from a cCBT intervention utilising Beating the Blues. Method: A systematic search across five databases was conducted, followed by manual searches. Strict search criteria were applied, resulting in the identification of 15 studies. These were subjected to quality assessment, data extraction and synthesis. For the empirical study, data from 1354 participants was collected, with subgroup-analyses conducted on those completing measures of life and mental health satisfaction, functioning and well-being. Key potential predictors of interest were level of group identification, baseline distress, and socioeconomic deprivation. Results: Findings from the systematic review indicated that staff held relatively positive attitudes towards cCBT, with some ambivalence emerging in relation to perceived advantages and disadvantages of the intervention. The empirical study obtained significant effects of group identification on life and mental health satisfaction. A mediating impact of group identity on baseline distress emerged, whereas a moderating effect of baseline distress on deprivation was obtained for the functioning model. Discussion: The current findings demonstrated both positive and negative aspects of staff attitudes towards cCBT for depression and/or anxiety, whereas the empirical project established a clear link between social identification, baseline distress, and well-being. Results from both studies are discussed in terms of clinical implications relating to the uptake of cCBT.
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Modeling and Growth of the 3C-SiC Heteroepitaxial System via Chloride ChemistryReyes-Natal, Meralys 24 October 2008 (has links)
This dissertation study describes the development of novel heteroepitaxial growth of 3C-SiC layers by chemical vapor deposition (CVD). It was hypothesized that chloride addition to the "traditional" propane-silane-hydrogen precursors system will enhance the deposition growth rate and improve the material quality via reduced defect density. Thermodynamic equilibrium calculations were performed to obtain a criterion for which chloride specie to select for experimentation. This included the chlorocarbons, chlorosilanes, and hydrogen chloride (HCl) chloride containing groups. This study revealed no difference in the most dominant species present in the equilibrium composition mixture between the groups considered. Therefore, HCl was the chloride specie selected to test the hypothesis.
CVD computerized fluid dynamic simulations were developed to predict the velocity, temperature and concentration profiles along the reactor. These simulations were performed using COMSOL Multiphysics and results are presented.
The development of a high-temperature (1300 °C -1390°C) 3C-SiC growth process resulted in deposition rates up to ~38 µm/h. This is the highest value reported in the literature to date for 3C-SiC heteroepitaxy. XRD FWHM values obtained varied from 220 to 1160 arcsec depending of the process growth rate or film thickness. These values are superior or comparable to those reported in the literature. It was concluded from this study that at high deposition temperatures HCl addition to the precursor chemistry had the most significant impact on the epitaxial layer growth rate.
Low-temperature (1000-1250°C) 3C-SiC growth experiments evidenced that the highest deposition rate that could be attained was ~2.5 µm/h. The best quality layer achieved in this study had a FWHM of 278 arcsec; which is comparable to values reported in the literature and to films grown at higher deposition temperatures in this study. It was concluded from this work that at lower deposition temperatures the HCl addition was more beneficial for the film quality by enhancing the surface. Surface roughness values for films grown with HCl additive were 10 times lower than for films grown without HCl.
Characterization of the epitaxial layers was carried out via Nomarski optical microscopy, FTIR, SEM, AFM, XRD and XPS.
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