O objetivo deste trabalho, foi investigar o comportamento tribológico do par cerâmico alumina - nitreto de silício no deslizamento em água com pH controlado e em uma suspensão com diferentes concentrações de sílica coloidal em água, e verificar a possibilidade de atingir um coeficiente de atrito da ordem de milésimos (&#956; < 0,01), aqui chamado de ultra baixo coeficiente de atrito (UBCA) e verificar se a mudança do pH do meio, ou a alteração da concentração de sílica na água, diminui o runningin, tempo necessário para o sistema entrar em regime estacionário, do coeficiente de atrito. Os ensaios foram realizados na configuração de ensaio tribológico esfera contra disco, no qual a esfera foi de nitreto de silício e o disco de alumina, sob carga normal de 54 N e velocidade de deslizamento de 1 m/s. A água utilizada nos ensaios foi destilada e deionizada, e a sílica coloidal amorfa, sem porosidade e de tamanho médio de partícula de 12 nanômetros foi a Aerosil® 200. A esfera de nitreto de silício, adquirida comercialmente, e o disco de alumina, foi proveniente de trabalhos anteriores. Todos os materiais foram caracterizados quanto a densidade. Algumas propriedades mecânicas como dureza, módulo de elasticidade e tenacidade à fratura foram determinadas. Nos ensaios lubrificados com água onde o pH foi controlado, o sistema atingiu o regime com valores de coeficiente de atrito da ordem de milésimos, exceto quando o pH da água era muito baixo ou muito alto. Em hidrossol o coeficiente de atrito chegou a unidades de milésimos, mas quando se aumenta a concentração de sílica coloidal, também, aumenta o desgaste nas superfícies. O disco de alumina sempre apresentou menor desgaste do que a esfera de nitreto de silício, em todas as condições estudadas. / The objective of this work was to investigate the tribological behavior of the ceramic pair alumina-silicon nitride, sliding on the water with controlled pH and in a suspension with different concentrations of colloidal silica in water, and verify the possibility of achieving a friction coefficient in the order of thousandths (&#956; < 0.01), here called ultra low friction coefficient (ULFC) and verify if the change of pH or changing the concentration of silica in the water, decreases the running-in, time required for the system reach the steady state of friction coefficient. The tests were conducted in a pin on disc setup in which the ball was made on silicon nitride and the disc of alumina, under normal load of 54 N and a sliding velocity of 1 m/s. The water used in the experiments was distilled and deionized. The amorphous silica, without porosity and average particle size of 12 nanometers was Aerosil ® 200. The ball of silicon nitride, was purchased commercially, and the alumina disk was recycled from previous works, all materials were characterized by density. Some mechanical properties such as hardness, elastic modulus and fracture toughness were determined. In tests with controlled pH water the system has reached the friction coefficient of the order of thousandths, except when the pH of the water was too low or too high. In hydrossol the friction coefficient reached units of thousandths, but when increasing the concentration of colloidal silica also increases the wear in the surfaces. The alumina disc always showed less wear than the ball of silicon nitride, in all conditions studied.

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.

Orientador: José Alexandre Diniz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-21T10:50:41Z (GMT). No. of bitstreams: 1 Silva_AudreyRoberto_M.pdf: 3023922 bytes, checksum: ee750f675d01f2b3ceebd5d74149b16e (MD5) Previous issue date: 2012 / Resumo: Este trabalho apresenta o desenvolvimento de células fotovoltaicas de junção n+/p em substratos de Si com processos de fabricação totalmente compatíveis com a tecnologia CMOS (Complementary Metal Oxide Semiconductor). Os processos compatíveis desenvolvidos neste trabalho sao as técnicas: i) de texturização da superfície do Si, com reflexao da superficie texturizada de 15% obtida com a formação de micro-pirâmides (alturas entre 3 e 7 ?m), utilizando-se solução alcalina de NH4OH (hidróxido de amônia), que e livre da contaminação indesejável por íons de Na+ e K+ quando se utiliza soluções tradicionais de NaOH e de KOH, respectivamente, e ii) de deposição ECR-CVD (Electron Cyclotron Resonance - Chemical Vapor Deposition) da camada antirrefletora (ARC) de SiNX (nitreto de silício), que e executada em temperatura ambiente, portanto pode ser feita apos a finalização da célula sem danificar trilhas metálicas e alterar a profundidade da junção n+/p. A caracterização desta camada ARC mostrou que o nitreto tem índice de refração de 1,92 e refletância mínima de 1,03%, o que e um excelente resultado para uso em células solares (ou fotovoltaicas). Foram fabricadas cinco series de células fotovoltaicas, utilizando-se a texturização com NH4OH e a camada antirrefletora de nitreto de Si. Em quatro series utilizou-se o processo de implantação de íons de fósforo (31P+), com posterior recozimento, para a formação da região n+, enquanto que na quinta serie foi utilizado o processo de difusão térmica. As eficiências máximas para as células fabricadas são de 9% e de 12%, respectivamente, para as células feitas utilizando os processos de implantação e de difusão térmica, indicando que a implantação de íons causa danos na rede cristalina do silício, que o posterior recozimento não consegue corrigir, o que reduz a eficiência da célula / Abstract: This work presents the development of photovoltaic cells based on n+/p junction in Si substrates, with fully compatible fabrication processes with CMOS technology. The compatible processes, which are developed in this study, are the techniques: i) of Si surface texturing, with the textured surface reflection of 15% obtained by the formation of micro-pyramids (heights between 3 and 7 ?m) using NH4OH (ammonium hydroxide) alkaline solution, which is free of undesirable contamination by Na + and K + ions, when NaOH and KOH traditional solutions are used, respectively, and ii) of the ECR-CVD (Electron Cyclotron Resonance - Chemical Vapor Deposition) deposition of SiNx (silicon nitride) anti-reflective coating (ARC), which is carried out at room temperature and can be performed after the end of cell fabrication without damage on metallic tracks and without variation of n+/p junction depth. The ARC coating characterization presented that the silicon nitride has a refractive index of 1.92 and a minimum reflectance of 1.03%, which is an excellent result for application in solar (or photovoltaic) cells. Five series of photovoltaic cells were fabricated, using the NH4OH solution texturing and the silicon nitride antireflective coating. In the first four series, phosphorus (31P+) ion implantation process, with subsequent annealing to get the region n+, was used, while, in the fifth series was used the thermal diffusion process. The maximum efficiency values are of 9% and 12%, respectively, for cells, which were fabricated using the ion implantation and thermal diffusion processes, indicating that the ion implantation damages the silicon crystal lattice and the subsequent annealing cannot rectify, which reduces the cell efficiency / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Laser surface treatment of engineering ceramics offers various advantages in comparison with conventional processing techniques and much research has been conducted to develop applications. Even so, there still remains a considerable gap in knowledge that needs to be filled to establish the process. By employing a fibre laser for the first time to process silicon nitride (Si3N4) and zirconia (ZrO2) engineering ceramics, a comparison with the CO2 and a Nd:YAG lasers was conducted to provide fundamental understanding of various aspects of the laser beam-material interaction. Changes in the morphology, microstructure, surface finish, fracture toughness parameter (K1c) were investigated, followed by thermal finite element modelling (FEM) of the laser surface treatment and the phase transformation of the two ceramics, as well as the effects of the fibre laser beam parameter - brightness (radiance). Fibre and CO2 laser surface treatment of both Si3N4 and ZrO2 engineering ceramics was performed by using various processing gases. Changes in the surface roughness, material removal, surface morphology and microstructure were observed. But the effect was particularly more remarkable when applying the reactive gases with both lasers and less significant when using the inert gases. Microcracking was also observed when the reactive gases were applied. This was due to an exothermic reaction produced during the laser-ceramic interaction which would have resulted to an increased surface temperature leading to thermal shocks. Moreover, the composition of the ceramics was modified with both laser irradiated surfaces as the ZrO2 transformed to zirconia carbides (ZrC) and Si3N4 to silicon dioxide (SiO2) respectively. The most appropriate equation identified for the determination of the fracture toughness parameter K1c of the as-received, CO2 and the fibre laser surface treated Si3N4 and ZrO2 was K1c=0.016 (E/Hv) 1/2 (P/c3/2). Surfaces of both ceramics treated with CO2 and the fibre laser irradiation produced an increased K1c under the measured conditions, but with different effects. The CO2 laser surface treatment produced a thicker and softer layer whereas the fibre laser surface treatment increased the hardness by only 4%. This is inconsiderable but a reduction in the crack lengths increased the K1c value under the applied conditions. This was through a possible transformation hardening which occurred within both engineering ceramics. Experimental findings validated the generated thermal FEM of the CO2 and the fibre laser surface treatment and showed good agreement. However, a temperature difference was found between the CO2 and fibre laser surface treatment due to the difference in absorption of the near infra-red (NIR) wavelength of the fibre laser being higher than the mid infra-red (MIR) wavelength of the CO2 laser. This in turn, generated a larger interaction zone on the surface that was not induced further into the bulk, as was the case with the fibre laser irradiation. The MIR wavelength is therefore suitable for Viability and Characterization of the Laser Surface Treatment of Engineering Ceramics 3 the surface processing of mainly oxide ceramics and surface treatments which do not require deep penetration. Phase transformation of the two ceramics occurred at various stages during the fibre laser surface treatment. The ZrO2 was transformed from the monoclinic (M) state to a mixture of tetragonal + cubic (T+C) during fibre laser irradiation and from T+C to T and then a partially liquid (L) phase followed by a possible reverse transformation to the M state during solidification. The Si3N4 transformed to a mixture of α-phase and β-phase (α→ α+β) followed by α+β and fully transforms from α+β → β-phase. What is more, is a comparison of the fibre laser-beam brightness parameter with that of the Nd:YAG laser. In particular, physical and microstructural changes due to the difference in the laser-beam brightness were observed. This research has identified the broader effects of various laser processing conditions, as well as characterization techniques, assessment and identification of a method to determine the K1c and the thermal FEM of laser surface treated engineering ceramics. Also, the contributions of laser-beam brightness as a parameter of laser processing and the influence thereof on the engineering ceramics have been identified from a fundamental viewpoint. The findings of this research can now be adopted to develop ceramic fuel cell joining techniques and applications where laser beam surface modification and characterization of engineering ceramics are necessary.

Magister Scientiae - MSc / Amorphous silicon nitride (a-SiN:H) thin films has a multitude of applications, stemming from the tunability of the material properties. Plasma enhanced chemical vapour deposition (PECVD) is the industrial workhorse for production of device quality a-SiN:H. However, this technique has drawbacks in terms of film quality, rooting from ion bombardment, which then results in undesirable oxidation. Hot wire chemical vapour deposition (HWCVD) has shown to be a viable competitor to its more costly counterpart, PECVD. A thin film produced by HWCVD lacks ion bombardment due to the deposition taking place in the absence of plasma. This study will focus on optimising the MVsystems ® HWCVD chamber at The University of the Western Cape, for production of device quality a-SiN:H thin films at low processing parameters. The effect of these parameters on the structural, optical and morphological properties was investigated, for reduction of production costs. The films were probed by heavy ion elastic recoil detection, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, atomic force microscopy, Xray diffraction, and ultraviolet visible spectroscopy. It was shown that silicon rich, device quality a-SiN:H thin films could be produced by HWCVD at wire temperatures as low as 1400 °C and the films showed considerable resistance to oxidation in the bulk.

Magister Scientiae - MSc / Technological advancement has created a market for large area electronics such as solar cells and thin film transistors (TFT’s). Such devices now play an important role in modern society. Various types of conducting, semiconducting and insulating thin films of the order of hundreds, or even tens of nanometres are combined in strata to form stacks to create interactions and phenomena that can be exploited and employed in these devices for the benefit of mankind. One such is for the generation of energy via photovoltaic devices that use thin film technology; these are known as second and third generation solar cells. Silicon and its alloys such as silicon germanium (SiGex), silicon oxide (SiOx), silicon carbide (SiCx) and silicon nitride (SiNx) play an important role in these devices due to the fact that each material in its different structures, whether amorphous, micro or nano-crystalline or completely crystalline, has its own range of unique optical, mechanical and electrical properties. These structures and their material properties can thus exert a huge influence over the overall device performance. viii Chemical vapour deposition (CVD) techniques are most widely used in industry to obtain thin films of silicon and silicon alloys. Source gases are decomposed by the external provision of energy thereby allowing for the growth of a thin solid film on a substrate. In this study a variant of CVD, namely Hot Wire Chemical Vapour Deposition (HWCVD) will be used to deposit thin films of silicon nitride by the decomposition of silane (SiH4), hydrogen (H2) and ammonia (NH3) on a hot tantalum filament (~1600 C). Hydrogenated amorphous silicon nitride (a-SiNx:H) has great potential for application in optoelectronic devices. In commercial solar cell production its potential for use as anti-reflection coatings are due to its intermediate refractive index combined with low light absorption. An additional benefit is the passivation of interface and crystal defects due to the bonded hydrogen. This can lead to better photon conversion efficiency. Its optical properties including optical band gap, Urbach tail, and wavelength-dependent optical constants such as absorption coefficient and refractive index are crucial for the design and application in the relevant optoelectronic device. The final firing step in the production of micro-crystalline silicon solar cells, allows hydrogen to effuse into the solar cell from the a-SiNx:H, and drives bulk passivation of the grain boundaries. We therefore propose the exploration of annealing effects on the thin film structure. The study undertakes a comparison of optical and bonding structure of the as deposited thin film compared to that of the annealed thin film which would have undergone changes due to high temperature annealing under vacuum. However, it is difficult to simultaneously obtain all of these important ix optical parameters for a-SiNx:H thin films. Ultraviolet visible (UV-vis) spectroscopy will be the method of choice to investigate the optical properties. Infrared (IR) spectroscopy is a source of useful information on the microstructure of the material. In particular, the local atomic bonding configurations involving Si, N, and H atoms in a-SiNx:H films can be obtained by Fourier Transform Infrared Spectroscopy (FTIR). Therefore, this study will attempt to establish a relationship between film microstructure of a-SiNx:H thin films and their macroscopic optical properties.

Orientadores: Leandro Tiago Manera, Arismar Cerqueira Sodré Júnior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-27T14:09:44Z (GMT). No. of bitstreams: 1 NascimentoJunior_AdrianoRicardo_M.pdf: 49523846 bytes, checksum: 938b4d8587e112835bf6e0988731ba04 (MD5) Previous issue date: 2015 / Resumo: Neste trabalho foram fabricados microrressonadores em anel com alto fator de qualidade utilizando filmes de nitreto de silício (SixNy) depositados a baixa temperatura (20 °C) utilizando a técnica de deposição ECR-CVD (Deposição em Fase Vapor por Resonância Ciclotrônica do Elétron). Graças à alta não linearidade do SixNy, tais filmes têm sido recentemente usados para aplicações em óptica não linear como a geração de pentes de frequência na banda C de telecomunicações. Para tais aplicações, o guia de onda do dispositivo deve possuir um ponto de dispersão nula no centro da banda C, necessitando de uma grande área. Infelizmente, filmes espessos de nitreto de silício (>400 nm) possuem um alto stress responsável pela ocorrência de rachaduras catastróficas no filme que reduzem drasticamente a eficiência do dispositivo. Utilizando simulações numéricas, demonstrou-se que para valores de índice de refração (n) maiores que 2, a área do guia de onda com zero dispersão em ? = 1,55 ?m é consideravelmente reduzida, necessitando assim de uma menor espessura de filme. Foi obtido um filme de SixNy rico em Si, com índice de refração igual a 2, alta taxa de deposição, baixa concentração de hidrogênio e uma rugosidade média de somente 0,52 nm (4,2 nm de desvio padrão). Devido à baixa temperatura da técnica de deposição empregada, não foi observado traços de stress no filme, permitindo a obtenção de uma espessura de 730 nm utilizando uma única etapa de deposição. Os microrressonadores ópticos fabricados com raios de 60 e 120 ?m apresentaram um FSR (Free Spectral Range) equidistante em toda a banda C e um fator de qualidade de 7,2x10^3 foi obtido experimentalmente. Tais resultados demonstraram a alta eficiência dos dispositivos fabricados com o filme de SixNy desenvolvido e sua promissora aplicação para óptica não linear na banda C de telecomunicações / Abstract: Silicon nitride (SixNy) films deposited by low-pressure electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-CVD) at room temperature are proposed for fabrication of microring resonators with high Q-factor. Due to the high silicon nitride nonlinearity, these films recently have also been used for nonlinear optics applications in the telecommunications C-band. For nonlinear applications such as the generation of frequency combs, the waveguide needs a zero dispersion point in the middle of C-band, requesting large waveguide area. Unfortunately, these thick SixNy films (>400 nm) have high stress and suffer from catastrophic cracking, which reduces the device efficiency. Using numerical simulations it was demonstrated that for refractive index (n) values greater than 2, the area of the waveguide with zero dispersion point at ? = 1.55 ?m is greatly reduced. A Si-rich silicon nitride layer with refractive index of 2, high deposition rate, low hydrogen concentration and roughness average of 0.52 nm with standard deviation of 4.2 nm was obtained. Due to the low temperature deposition, no thermal stress was observed in the SixNy film, allowing a thickness of 730 nm obtained with only one deposition step. After experimental measurements, microring resonators having a radius of 60 and 120 ?m, presented an equidistant Free Spectral Range and a Q-factor of 7.2x10^3 was achieved, showing the high efficiency of the device and their promising application in nonlinear effects in the telecommunication C-band / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Silicon photonics has become one of the leading candidates for the next generation optical communication platform. In addition to being an inexpensive material and compatible with Complementary metal–oxide–semiconductor (CMOS) manufacturing, silicon exhibits low absorption at optical telecommunication bands. However, high propagation loss and poor light confinement in narrow Si waveguides have limited high-density optical integration.<br>In this work, we show the fabrication and characterization of a novel type of devices named E-skid devices that can reduce the skin depth and suppress the large spatial content of evanescent light. These devices use artificial anisotropic dielectric metamaterial to suppress the evanescent waves. Beside E-skid devices, we also discuss the fabrication and experimental characterization of mode filters using Silicon on Insulator that can block the fundamental TE0 and allow the higher order modes to pass through using Multi Mode Interference.<br>In this work, the mode is filtered using radiation, not by reflection.<br>Beside Silicon, Silicon Nitride has also gained much interest because of its low loss, smaller nonlinear absorption and higher Kerr effect. Silicon Nitride waveguides have widely<br>been used for lots of applications specially the optical frequency comb generation. One special case of coherent optical frequency comb is Soliton in which case the non-linearity and dispersion cancel each other’s effect and keep the pulse without distortion. In this work, we described the Silicon Nitride fabrication process and did a comparative analysis with other research groups who fabricates similar devices. We tried to improve our process by inserting a few additional steps in our fabrication process. We also investigated our process step by step and found out reasons for our low quality factor and low yield. We found a few factors that might be responsible for the low quality factor and addressed them. We fabricated real devices using our modified process and saw improvement in quality factors, yield and thermal performance of the devices.<br>Finally, we describe an edge polishing method for Silicon Nitride microring resonator devices, which we developed from scratch and we can polish edges down to sub-micron level. Thus, the edges become optically flat and it allowed us to do heterogeneous integration with an Indium Phosphide chip. This paves away for some exciting opportunities like on-chip frequency comb generation.<br><br>

En s’appuyant sur les procédés de fabrication matures et sur la production à grande échelle de l’industrie CMOS, la technologie photonique silicium est une solution potentielle pour le développement de liens optiques haut débit peu onéreux destinés aux centres de données. Un premier pas a été franchi il y a une dizaine d’année avec la réalisation, à l’échelle industrielle, de transmetteurs/récepteurs avec des débits jusqu’à 100Gb/s. Cependant, tout semble indiquer que des vitesses encore plus élevées, (200 voir 400Gb/s), seront bientôt nécessaires. Malheureusement, les limitations techniques de cette première génération de circuits photoniques suggèrent qu’il sera difficile de réaliser des multiplexeurs (MUX/DEMUX) performants. Ces composants sont à la base des solutions de multiplexage en longueur d’onde (WDM) envisagées pour répondre à cette nouvelle demande de bande passante. Par ailleurs, on assiste depuis quelques années à une diversification des applications de la photonique intégrée qu’il semble également difficile de satisfaire au vu des performances de la technologie actuelle. C’est dans ce contexte que s’inscrit le travail de thèse présenté dans ce manuscrit. La solution étudiée est basée sur l’intégration d’un second circuit optique dont les propriétés sont complémentaires de celles du circuit silicium formant ainsi une plateforme optique performante quelle que soit la fonction à réaliser. Un schéma d’intégration monolithique a été privilégié afin de limiter les couts de production et d’assemblage. Le matériau choisi pour la réalisation de ce second circuit optique est le nitrure de silicium (SiN). Il possède en effet des propriétés parfaitement complémentaires de celles du circuit silicium : contraste d’indice réduit, coefficient thermo optique faible et grande gamme de transparence. C’est également un matériau utilisé depuis de nombreuses années dans l’industrie CMOS. Le premier objectif de ce travail de thèse a donc consisté à développer le schéma d’intégration de ce second circuit optique au sein de la technologie photonique PIC50G de STMicroelectronics. Une fois les différentes étapes du flot de fabrication validées, le développement de composants a pu débuter. Tout d’abord les guides d’onde, proposant des pertes de propagation inférieures à 0,2dB/cm à 1300nm, mais également divers composants élémentaires : transitions entre les différentes géométries de guides, coupleur fibre/puce, terminaison de guide d’onde, filtre de signaux parasites et coupleurs/séparateurs de puissance. Une caractérisation statistique de la transition optique entre les circuits Si et SiN a révélé des pertes d’insertion inférieures à 0,3dB entre 1270nm et 1330nm, validant la stabilité de ce composant particulièrement critique. Une attention particulière a été portée à la gestion de la polarisation dans les guides d’onde via le développement de séparateurs et de rotateurs de polarisation dont les performances sont à l’état de l’art des composants silicium. Une étude complète sur les MUX/DEMUX en SiN a également été réalisée. Des réseaux de guides d’onde ont notamment montré de bonnes performances : dérive en température < 12pm/°C, faible sensibilité à la polarisation, pertes d’insertion <1dB, diaphonie < -30dB, fonctionnement jusqu’à 12 canaux, bande passante à -1dB >11nm. Pour terminer, un émetteur/récepteur WDM quatre canaux a été conçu pour démontrer l’intérêt de cette plateforme hybride Si/SiN, il est actuellement en attente de caractérisation. Enfin, une étude des propriétés optiques non linéaires du SiN a permis de démontrer la génération de troisième harmonique de l’UV jusqu’au visible ainsi que la génération d’un supercontinuum s’étendant de 425nm à 1660nm, ouvrant ainsi la voie à de nouvelles applications. / Based on CMOS industry's mature manufacturing processes and large-scale production, silicon photonics technology is a potential solution for inexpensive high-speed optical links for data centers. About ten years ago, a first step was taken with the realization, at an industrial scale, of transmitters/receivers with data rates up to 100Gb/s. However, it seems that even higher speeds (typically 200 or 400Gb/s) will soon be needed. Unfortunately, the technical limitations of this first generation of photonic circuits suggest that it will be difficult to make efficient multiplexers (MUX / DEMUX), which form the basis of wavelength division multiplexing (WDM) solutions designed to meet this new bandwidth demand. Moreover, a diversification of the applications of integrated photonics is ongoing for a few years, which also seems difficult to satisfy given the performance of current technology. The thesis work presented in this manuscript yielded from this context. The studied solution is based on the integration of a second optical layer whose properties are complementary to those of the silicon circuit. This forms an integrated optical platform which can be efficient whatever the function to be performed. A monolithic integration scheme is chosen leveraging the low cost and manufacturing capability of CMOS industry. Silicon nitride (SiN), with a reduced index contrast and a low thermo-optical coefficient, is an interesting candidate for the realization of this second photonic circuit. Indeed, those properties are perfectly complementary to the silicon ones, and particularly adapted to the realization of MUX/DEMUX. Moreover, SiN is a well-known material of CMOS electronics. The first objective of this thesis was to develop the integration scheme of the second optical circuit within ST Microelectronics PIC50G photonic technology. Once all the fabrication steps validated, the development of photonic devices could begin. It starts with several kinds of optical waveguides, among which rib-type demonstrated propagation losses below 0.2dB/cm at 1300nm, but also various elementary components: transitions between waveguides, fiber/chip coupler, waveguide termination, parasitic signals filters and power splitters/combiners. A statistic characterization of the optical transition between Si and SiN circuits reveal insertion losses below 0,3dB from 1270nm to 1330nm, confirming the stability of this critical device. Special attention was paid to the polarization management within the SiN circuit. Polarization splitters and rotators were developed showing comparable performances with Si devices state of the art. An exhaustive study about the realization of SiN MUX/DEMUX was also carried out. Arrayed waveguide gratings especially show good performances: thermal drift < 12pm/°C, low polarization sensitivity, insertion loss <1dB, crosstalk level < -30dB, up to twelve channels, -1dB bandwidth >11nm. To conclude this work, a four channel WDM transmitter/receiver was designed in order to demonstrate the interest of this hybrid Si/SiN platform, its currently waiting for characterization. Finally, a study of the nonlinear properties of SiN demonstrated the generation of a third harmonic optical signal from UV to visible and the generation of a supercontinuum spanning from 425nm to 1660nm, paving the way to new applications.

Identifying the protein content in a cell in a fast and reliable manner has become a relevant goal in the field of proteomics. This thesis computationally explores the potential for silicon nitride nanopores to sense and distinguish single miniproteins, which are small domains that promise to facilitate the systematic study of larger proteins. Sensing and identification of these biomolecules using nanopores happens by studying modulations in ionic current during translocation. The approach taken in this work was to study two miniproteins of similar geometry, using a cylindrical-shaped pore. I employed molecular mechanics to compare occupied pore currents computed based on the trajectory of ions. I further used density functional theory along with relative surface accessibility values to compute changes in interaction energies for single amino acids and obtain relative dwell times. While the protein remained inside the nanopore, I found no noticeable differences in the occupied pore currents of the two miniproteins for systems subject to 0.5 and 1.0 V bias voltages. Dwell times were estimated based on the translocation time of a protein that exhibits no interaction with the pore walls. I found that both miniproteins feel an attractive force to the pore wall and estimated their relative dwell times to differ by one order of magnitude. This means even in cases where two miniproteins are indistinguishable by magnitude changes in the ionic current, the dwell time might still be used to identify them. This work was an initial investigation that can be further developed to increase the accuracy of the results and be expanded to assess other miniproteins with the goal to aid future experimental work.