Neste trabalho apresentamos os resultados da deposição e caracterização de filmes de oxinitreto de silício (SiOxNy) pela técnica de deposição química a vapor assistida por plasma (PECVD) à baixas temperaturas (320oC). O objetivo deste trabalho é obter filmes de ligas amorfas de silício, oxigênio e nitrogênio com composição química ajustável de forma contínua desde à do SiO2 até a do Si3N4 visando sua aplicação em dispositivos ópticos e eletrônicos. Os filmes foram crescidos a partir de duas misturas gasosas (silano, óxido nitroso e nitrogênio) e (silano, óxido nitroso e amônia) e a relação entre os fluxos dos gases foi variada de forma a obter as composições químicas desejadas na fase sólida. Foi procurado também obter filmes com alta e baixa taxa de deposição, para as diferentes aplicações. Os filmes foram caracterizados através da técnica de espectroscopia por retroespalhamento Rutherford (RBS) para a obtenção da composição química, espectroscopia de absorção no infravermelho (FTIR) para a determinação das ligações químicas, elipsometria para a determinação de propriedades ópticas como índice de refração e a técnica de X-ray Absorption Near Edge Structure (XANES) para o estudo de estrutura de ordem local e média em torno de uma determinada espécie atômica. Os resultados demonstraram que com as duas misturas gasosas é possível variar a composição dos filmes de forma contínua permitindo assim um controle preciso das concentrações atômicas e, portanto, um bom controle do índice de refração. Os filmes não apresentaram incorporação significativa de ligações Si-H, tornando-os bons candidatos para as aplicações em dispositivos optoeletrônicos. A incorporação de nitrogênio foi mais eficiente para as amostras crescidas com NH3 em comparação às crescidas com N2. As amostras de baixa taxa de deposição apresentaram densidades semelhantes, podendo ser utilizada qualquer uma das misturas gasosas na produção dos filmes. Para a obtenção de filmes espessos, as amostras crescidas com nitrogênio apresentaram melhores características quanto a densidade em comparação às crescidas com amônia. / In this work, we present results on the deposition and characterization of silicon oxynitride films (SiOxNy) deposited by plasma enhanced chemical vapor deposition (PECVD) at low temperatures (320ºC). Our goal is to obtain silicon, oxygen and nitrogen amorphous alloys with tunable chemical composition from silicon dioxide to stoichiometric silicon nitride, for optical and electronic applications. The films were grown from two different gaseous mixtures: (silane, nitrous oxide and nitrogen) and (silane, nitrous oxide and ammonia). The flow ratio among these precursor gases was varied in order to obtain the desired chemical composition in the solid phase. We also sought to obtain films with high and low deposition rate, for the different applications. The films were characterized by Rutherfor Backscatering spectroscopy (RBS) to obtain the chemical composition, by Fourier Transform Infrared (FTIR) to determine and chemical bonds, by elipsometry to determine the optical properties such as refractive index and by the X-ray Absorption Near Edge Structure (XANES) to study the local and medium order structure. The results demonstrated that with the two gaseous mixtures is possible to obtain films with chemical composition varying in a continuous way, thus allowing a precise control of the atomic concentration and, therefore, of the refractive index. The films do not show significant incorporation of Si-H bonds, making then good candidates for optoelectronic devices applications. The nitrogen incorporation was more efficient in samples grown with NH3 in comparison with those grown with N2. The low deposition rate samples presented similar density, so anyone of these gaseous mixtures can be utilized for film production. To obtain thick films nitrogen precursor mixtures lead to better material properties than ammonia mixtures.

On s'est intéressé dans ce travail à l'élaboration, la caractérisation et la modélisation des propriétés optiques d'une nouvelle génération de cristaux photoniques hybrides à une dimension à base d'un composé organique l'hexaméthyldisiloxane dilué dans l'oxygène ou l'azote, et pur en alternance avec le silicium. Après un bref rappel sur l'historique des cristaux photoniques, et leur originalité qui réside en l'existence de bandes interdites photoniques (BIP) qui sont à la base de leurs applications potentielles dans la communication optique et l'optoélectronique. Nous avons ensuite présenté les matériaux de base utilisés pour l'élaboration de nos cristaux photoniques et qui sont: l'hexaméthyldisiloxane (HMDSO) et le silicium, qu'on a déposé en couches minces par les techniques de PECVD et de pulvérisation cathodique magnétron RF. La composition de ces couches a été analysée par spectroscopie infrarouge à transformé de Fourrier et leurs indices de réfraction déterminés par spectroscopie de transmission et de réflexion. Les deux premiers cristaux photoniques hybrides sont issus de même matériaux organiques le HMDSO qu'on a dilué respectivement avec l'oxygène et l'azote. Pour le premier cristal nous avons fait varier le flux d'oxygène jusqu'à obtenir des nouvelles phases formées de HMDSO et SiO2. Pour le deuxième cristal nous avons dilué le HMDSO avec l'azote en faisant varier la puissance RF de dépôt jusqu'à obtenir deux phases formées de SiCxNyOzH et -Si3N4. Les deux cristaux photoniques sont ainsi de matériau présentant un bon contraste d'indice propice à l'émergence de la bande interdite photonique. Le troisième cristal photonique hybride est quant à lui constitué des couche de HMDSO pur alternées avec des couches de silicium. Nous avons interprété les résultats expérimentaux à l'aide d'un modèle théorique basé sur la méthode de matrice de transfert. Enfin nous avons étudié dans les trois cristaux photoniques l'effet d'incorporation des défauts et nous avons montré l'existence de mode localisé à l'intérieur de la bande interdite photonique / In this work, we focused on the elaboration, characterization and modelization of the optical properties of a new generation of one-dimensional hybrid photonic crystals based from an organic compound hexamethyldisiloxane diluted in oxygen or nitrogen, and pure alternating with silicon. After a brief review of the history of photonic crystals, their originality lies in the existence of photonic band gaps (BIPs) which are the basis of their potential applications in optical communication and optoelectronics. Then we presented the basic materials used for the production of our photonic crystals, which are: hexamethyldisiloxane (HMDSO) and silicon, which have been deposited in thin layers by PECVD and RF magnetron sputtering techniques. The composition of these layers was analyzed by Fourrier transform infrared spectroscopy and their refractive indixes determined by transmission and reflection spectroscopy. The two hybrid photonic crystals were obtained from the same organic materials HMDSO which were diluted with oxygen and nitrogen, respectively. For the first crystal we have varied the flow of oxygen and we obtain a new phases formed of HMDSO and SiO2. For the second crystal we have diluted the HMDSO with nitrogen by varying the RF deposition power until two phases are formed of SiCxNyOzH and -Si3N4. These two photonic crystals are thus materials presenting a good contrast of index leads to the emergence of the photonic band gap. The third hybrid photonic crystal consists of layers of pure HMDSO alternating with layers of silicon. We have interpreted the experimental results using a theoretical model based on the transfer matrix method. Finally, we studied in the three photonic crystals the effect of incorporation of the defects and we have shown the existence of located mode within the photonic band gap

The purpose of this research was to deposit the protective diamond-like carbon (DLC) films on polycarbonate substrates for optical applications. In this study, by using the PECVD method is the better way to deposit DLC film on polycarbonate substrates since the whole process were performed at low temperature to avoiding any degradation of the adhesion of DLC film on polycarbonate substrates occurred at high temperature. In order to further increase the adhesion between the polycarbonate substrates and the DLC film, we deposited the SiO2 layer as an interlayer, and select HMDSO as precursor because it contain Si and O atoms. It is because that SiOx films that can be deposited from HMDSO/oxyzen feeds are relatively hard and against mechanical damages due to forming the glass-link structure. In addition, SiOx films are fully transparent in the UV range and decrease the difference of TCE ( thermal expansion coefficient) of PC and coating films. In experiments, it is preceded being focus on the analysis of Raman spectrum for the films grown at various CH4 gas fluxes, substrates bias voltages, Si-doping concentrations and the distance of electrode separation. The dependence of the intensity ratio of D-band and G-band ( ID/IG ) on the surface roughness, hardness and mechanical properties were investigated, and the adhesion of coating layer depends on the thickness of intermediate layer were studied under various substrate bias voltage. At least, the properties of diamond-like carbon (DLC) film coatings on phase-change recording media were characterized by Raman spectroscopy, atomic force microscope (AFM), UV-visible spectrometer and disc testers. The dependence of mechanical, optical and structural properties of DLC films included the characteristics of surface roughness, hardness, transmittance and electrical signals of discs on serveral DLC film thicknesses were investigated. Our experimental results indicate that DLC films provide a suitable coating to protect PC substrate and make it no difference for data stored on phase-change optical discs.

Chemnitz, Techn. Univ., Diplomarb., [2005].

Neste trabalho apresentamos os resultados da deposição e caracterização de filmes de oxinitreto de silício (SiOxNy) pela técnica de deposição química a vapor assistida por plasma (PECVD) à baixas temperaturas (320oC). O objetivo deste trabalho é obter filmes de ligas amorfas de silício, oxigênio e nitrogênio com composição química ajustável de forma contínua desde à do SiO2 até a do Si3N4 visando sua aplicação em dispositivos ópticos e eletrônicos. Os filmes foram crescidos a partir de duas misturas gasosas (silano, óxido nitroso e nitrogênio) e (silano, óxido nitroso e amônia) e a relação entre os fluxos dos gases foi variada de forma a obter as composições químicas desejadas na fase sólida. Foi procurado também obter filmes com alta e baixa taxa de deposição, para as diferentes aplicações. Os filmes foram caracterizados através da técnica de espectroscopia por retroespalhamento Rutherford (RBS) para a obtenção da composição química, espectroscopia de absorção no infravermelho (FTIR) para a determinação das ligações químicas, elipsometria para a determinação de propriedades ópticas como índice de refração e a técnica de X-ray Absorption Near Edge Structure (XANES) para o estudo de estrutura de ordem local e média em torno de uma determinada espécie atômica. Os resultados demonstraram que com as duas misturas gasosas é possível variar a composição dos filmes de forma contínua permitindo assim um controle preciso das concentrações atômicas e, portanto, um bom controle do índice de refração. Os filmes não apresentaram incorporação significativa de ligações Si-H, tornando-os bons candidatos para as aplicações em dispositivos optoeletrônicos. A incorporação de nitrogênio foi mais eficiente para as amostras crescidas com NH3 em comparação às crescidas com N2. As amostras de baixa taxa de deposição apresentaram densidades semelhantes, podendo ser utilizada qualquer uma das misturas gasosas na produção dos filmes. Para a obtenção de filmes espessos, as amostras crescidas com nitrogênio apresentaram melhores características quanto a densidade em comparação às crescidas com amônia. / In this work, we present results on the deposition and characterization of silicon oxynitride films (SiOxNy) deposited by plasma enhanced chemical vapor deposition (PECVD) at low temperatures (320ºC). Our goal is to obtain silicon, oxygen and nitrogen amorphous alloys with tunable chemical composition from silicon dioxide to stoichiometric silicon nitride, for optical and electronic applications. The films were grown from two different gaseous mixtures: (silane, nitrous oxide and nitrogen) and (silane, nitrous oxide and ammonia). The flow ratio among these precursor gases was varied in order to obtain the desired chemical composition in the solid phase. We also sought to obtain films with high and low deposition rate, for the different applications. The films were characterized by Rutherfor Backscatering spectroscopy (RBS) to obtain the chemical composition, by Fourier Transform Infrared (FTIR) to determine and chemical bonds, by elipsometry to determine the optical properties such as refractive index and by the X-ray Absorption Near Edge Structure (XANES) to study the local and medium order structure. The results demonstrated that with the two gaseous mixtures is possible to obtain films with chemical composition varying in a continuous way, thus allowing a precise control of the atomic concentration and, therefore, of the refractive index. The films do not show significant incorporation of Si-H bonds, making then good candidates for optoelectronic devices applications. The nitrogen incorporation was more efficient in samples grown with NH3 in comparison with those grown with N2. The low deposition rate samples presented similar density, so anyone of these gaseous mixtures can be utilized for film production. To obtain thick films nitrogen precursor mixtures lead to better material properties than ammonia mixtures.

Zugl.: Dresden, Techn. Univ., Diss., 2008

Orientador: Fernando Alvarez / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-24T22:24:16Z (GMT). No. of bitstreams: 1 Antunes_ViniciusGabriel_M.pdf: 3019304 bytes, checksum: 07f935b74d9527a192ce26b38e17afda (MD5) Previous issue date: 2014 / Resumo: Os tratamentos de superfície a plasma são amplamente usados em diversas áreas de tecnologia, tais como: indústria metalmecânica, microeletrônica, plástico e medicina, para o crescimento de filmes finos, camadas protetoras em instrumentos e ferramentas de corte, funcionalização de superfícies plásticas, tecidos sintéticos, esterilização de instrumentos cirúrgicos e plasma reativo em semicondutores. Há alguns anos, uma nova família de filmes duros e protetores com baixo atrito compostos por nanoestrururas, tem sido intensamente pesquisada por apresentar propriedades particularmente interessantes, do ponto de vista da físico-química básica, como possíveis aplicações tecnológicas em que a demanda por desgaste, altas temperatura, e resistência mecânica são necessárias. A deposição de filmes finos, constituídos por nanocompósitos, e a compreensão de propriedades (mecânicas, elétricas, ópticas) desses novos materiais, gera um leque de possíveis aplicações tecnológicas. A partir de tais premissas, focalizamos o objetivo do trabalho em estudar a obtenção e caracterização das propriedades físico-químicas de filmes finos nanoestruturados (nanocompósitos), que contêm compostos de Ti, C, N, e O, utilizando a técnica de Deposição Química pela Decomposição do precursor líquido tetraetóxido de titânio (Ti(OC2H5)4) (PECVD, na sigla em inglês). Ressalta-se que o interesse em obter esses materiais, a partir do reagente em questão, reside no fato de que ele poderia substituir o uso de outros precursores de difícil manuseio, tais como o tetracloreto de titânio (TiCl4), o qual é normalmente utilizado em numerosas aplicações de deposições de filmes compósitos, mediante a técnica de PECVD, e cujo subproduto da reação gera reagentes altamente corrosivos. Em resumo, este trabalho contempla a caracterização da composição química, micro e nano estrutura de compósitos que contêm os compostos mencionados, em função das variáveis mais importantes de deposição. O presente estudo foi bem sucedido em obter nanocompósito e correlacionar a dependência das ligações químicas do material com os parâmetros mais importantes de deposição / Abstract: Plasma surface treatments are widely used in several technological areas (e.g., metallurgic industry, microelectronic, plastic industry, medicine) in order to obtain hard coatings on cutting tools and instruments, funtionalization of plastics and synthetic materials used in the textile industry, sterilization of chirurgic instruments, etching by reactive plasma in the semiconductor industry, etc. Recently, a new family of coatings deposited by plasma assisted techniques owing interesting physical chemical properties such as super-hardness, low friction and wear resistant, temperature and corrosion resistant, known as nano-composites, have been intensely studied.The objectives of this work is developing a nano composite containing Ti, C, N e O and understand as far as possible its physical and chemical properties. The material is obtained by plasma assisted enhanced chemical deposition (PECVD) using Titanium(IV) ethoxide ( (Ti(OC2H5)4) and N as precursors of the reaction. The importance of the attempt to use the cited precursor resides in the fact that it is a friendly liquid without corrosive o major toxic effects, as the normal precursors used in the actual industrial process (e.g., titanium tetrachloride, TiCl4). Summarizing, this work is focusing the research in the deposition and study of the physical and chemical properties of thin films nano composites obtained from Titanium(IV) ethoxide precursor. The study shows that the deposition procedure allows obtaining a material containing nanoscopics size crystallites of the compounds cited above. Finally, the relation of the material properties with the more important deposition parameters is discussed and presented / Mestrado / Física / Mestre em Física

Les films minces de Diamond-Like Carbon sont couramment employés dans les moteurs automobiles. Leur très faible coefficient de frottement et leur haute dureté permettent en effet d’optimiser les performances et la durée de vie des véhicules. Cependant, la plupart des lubrifiants utilisés dans les moteurs sont élaborés pour fonctionner avec des surfaces métalliques. Il est donc envisageable d’améliorer le comportement tribologique de films de DLC en leur conférant un caractère métallique par l’introduction d’éléments dopants en quantité limitée et contrôlée (15 % au maximum) dans la matrice de carbone amorphe. Un réacteur de dépôt industriel muni d’une technologie de dépôt hybride a été utilisé. Celle-ci combine la PECVD pour l’élaboration du DLC hydrogéné à la pulvérisation cathodique magnétron pour le dopage. Quatre éléments ont été introduits à différentes concentrations dans le DLC : aluminium, cuivre, molybdène et niobium. Les propriétés physico-chimiques des dépôts ont été caractérisées par XPS (composition et liaisons chimiques) et spectroscopie Raman (structure). La dureté, le frottement et l’usure à sec et en conditions lubrifiées, ainsi que l’énergie de surface des films ont également été caractérisés. Deux études in situ de tenue des DLC en température ont été conduites par spectroscopie Raman. Par comparaison avec un film de DLC pur, le dopage entraîne une modification de la structure du DLC, et par conséquent une réduction de la dureté des couches. Cependant, excepté dans le cas du cuivre, ceci s’accompagne d’une diminution significative du coefficient de frottement et de l’usure à sec des couches. En revanche, en dépit de ce résultat prometteur, l’impact sur les propriétés tribologiques en milieu lubrifié est plus modéré et fortement lié à la composition du lubrifiant employé. Enfin le transfert industriel du dopage a été étudié et validé dans le cas du dopage à l’aluminium. / Diamond-Like Carbon thin films are commonly used in automotive engines. Thanks to their very low friction coefficient and high hardness, it is indeed possible to optimize the performances and the lifetime of vehicles. However, most of the lubricants that are used in engines are designed to be in contact with metallic surfaces. So it might be possible to improve the global tribological behaviour of DLC films by giving them a metallic character. This can be achieved with the introduction of doping elements in limited and controlled amount (maximum 15 at. %) in the amorphous carbon matrix. An industrial scale reactor has been used with a hybrid coating technology combining PECVD for the deposition of hydrogenated DLC and magnetron sputtering for the introduction of the dopants. Four elements have been tested with various amounts in the DLC: aluminium, copper, molybdenum and niobium. The physico-chemical properties of the films have been characterized by XPS (chemical composition and bonding) and Raman spectroscopy (structure). Hardness, friction and wear in both dry and lubricated conditions, and surface energy have also been determined. Two in situ studies under temperature have been conducted by Raman spectroscopy for deposited thin films. Compared to a pure DLC, doping led to a modification of the structure resulting in a decrease in hardness. However, except for copper doping, a significant reduction of friction and wear in dry conditions is observed. Despite this promising result, the impact of doping on lubricated tribological behaviour is limited and strongly dependent on the composition of the lubricant itself. Finally, the industrial transfer of DLC metallic doping has been studied and validated.

Le but de ces travaux était de développer des membranes non oxydes a-SiCxNy:H par PECVD, permsélectives à H2 et avec une bonne stabilité hydrothermale jusqu’à 400° C, afin d’envisager la mise au point d’un module membranaire s’intégrant dans une chaîne de purification de l’hydrogène. Des dépôts ont été réalisés dans deux types de réacteurs PECVD basse-fréquence (BF) et micro-ondes (MO), en utilisant les précurseurs HMDSN et NH3, et l’argon en tant que gaz vecteur. Dans un premier temps, différentes conditions de synthèse ont été étudiées afin d’obtenir une riche variété de matériaux déposés en couche mince soit sur silicium monocristallin (pour caractérisations physico-chimiques), soit sur supports mésoporeux plans (pour caractérisation du transport de gaz). Dans le réacteur BF, les paramètres tels que la température (25 - 300° C) et la pression en NH3 (0 - 0,4 mbar) lors de la synthèse ont été étudiés. En réacteur MO, ces études ont été complétées par la variation de la puissance (100 – 200W). L’influence de ces paramètres sur structure microporeuse des matériaux a été prouvée, et des corrélations avec les performances des membranes pour la séparation d’hydrogène ont été établies. Pour les deux types de réacteurs, un comportement de tamis moléculaire avec un bon compromis entre perméance et sélectivité pour He a été démontré. Dans un second temps, les travaux se sont tournés vers un transfert de la technologie vers l’industrie a été considéré en deux étapes. La première étape du transfert a été de remplacer les gaz purs (He, N2, CO2) par un mélange gazeux (H2/CO/CO2/CH4) sec ou sous atmosphère humide, en conservant la géométrie plane pour les supports. Les résultats prouvent que, malgré une légère diminution de la perméance pour les gaz de petites tailles inhérent au remplacement de He par H2, les membranes restent efficaces pour la séparation de H2. De plus, la présence d’humidité à 150° C semble augmenter les performances et prouve la stabilité hydrothermale des membranes à cette température. La seconde étape du transfert concerne le passage d’une géométrie de substrat plane à tubulaire avec dépôt des membranes PECVD sur la surface externe des supports tubulaires. Les résultats montrent que la qualité de surface de ces substrats est principalement responsable de la diminution des performances des membranes, même si la stabilité hydrothermale semble être conservée. / The aim of this work was to develop innovative a-SiCxNy:H membranes prepared by PECVD, with good selectivity for gas with small kinetic diameters (H2/He) and with good hydrothermal stability. For this purpose, membrane depositions were carried out in two types of reactors (low frequency LF and microwave MW) using both HMDSN and NH3 as precursors and argon as a carrier gas. First, different synthesis conditions were investigated in order to obtain a large range of materials deposited as thin layers on monocrystalline silicon (for physicochemical characterizations) and mesoporous planar substrates (for membrane characterization). In the LF reactor, parameters such as deposition temperature and NH3 pressure during the synthesis were studied. In MW reactor, these studies were supplemented by the change of electric power applied to the plasma. The influence of these parameters on the microporous structure of the materials has been proven, and correlations with the membranes ability to selectively permeate hydrogen have been established. For both types of reactors, a molecular sieving behavior was obtained with the following performance: single gas He permeance > 10-7 mol.m-2.s-1.Pa-1 and He/CO2 ideal selectivity = 50 at 400°C. Secondly, the first steps for a transfer of this lab scale technology towards industry are investigated. At first, single gas (He, N2 and CO2) were replaced by a gas mixture containing H2, CO, CO2 and CH4 for studying separation factors both in dry and wet conditions, while keeping a planar mesoporous substrate. The results showed that, despite a slight decrease in H2 permselectivity, the membrane was still a good candidate for this purpose. In addition, the presence of moisture at 150°C seemed to slightly increase performance and proved the hydrothermal stability of the membrane at this temperature. The second step corresponds to the transfer from planar to tubular geometry, with the PECVD membranes deposited on the outer surface of the tubes. The results showed that the geometric stresses and the possible mesoscopic defects of these substrates greatly reduced the H2 selectivity of the deposited a-SiCxNy:H membrane materials, although their molecular sieving behavior and thermal stability at 400°C were kept.

This thesis presents results on the applications and limitations of plasma enhanced chemical vapour deposition for silicon-based photonics, with an emphasis on optical microcavities for the control of light emission from silicon nanocrystals. ¶ Silicon nanocrystals were formed by precipitation and growth within Si-rich oxide layers (SiOx) deposited by plasma enhanced chemical vapour deposition. The films were found to exhibit strong room temperature photoluminescence, with the optimum emission depending on the composition and processing of the films. The strongest emission was achieved for films with a silicon content of ~40%, following hydrogen passivation. Hydrogen was introduced into the samples by two different methods: by annealing in forming gas (95% N2: 5% H2) or by annealing with a hydrogenated silicon nitride capping layer. Both methods caused an increase in photoluminescence intensity due to the passivation of defects. In contrast, the presence of low levels of iron and gold were shown to reduce the concentration of luminescent nanocrystals due to the creation of non-radiative centres. ¶ Optical microcavity structures containing silicon nanocrystals were also fabricated by Plasma enhanced chemical vapour deposition, using silicon dioxide, silicon nitride and silicon-rich oxide layers. The microcavities consisted of a silicon-rich oxide layer between two distributed Bragg reflectors formed of alternating silicon dioxide/nitride layers. The optical emission from these and related structures were examined and compared with that from individual layers in the structure. This revealed a complex interplay between defect and nanocrystal luminescence, hydrogen passivation and materials structure. The resulting microcavity structures were shown to be suitable for producing a stop-band over the wavelength range of interest for nanocrystal emission, 500-1000nm, and to produce significant intensity enhancement and spectral narrowing. Quality factors of 50-200 were demonstrated. ¶ The application of plasma deposited films was shown to be limited by stress-induced failure that resulted in cracking and delamination of the films during annealing. The SiOx films thicker than about 600nm failed predominantly by cracking. This was shown to be caused by tensile stress in the film caused by hydrogen desorption during high temperature annealing. The resulting cracks showed preferred alignment depending on the crystallographic orientation of the silicon substrate. For films deposited on (100) silicon, two modes of crack propagation were observed, straight cracks aligned along < 100> directions, and wavy cracks aligned along < 110> directions. For films deposited on (110) silicon, straight cracks were observed along [-1 10] directions, with a lesser number aligned along [001] directions. Cracks were also observed for films on (111) silicon. These showed 3-fold symmetry consistent with crack propagation along < 211> directions due to plastic deformation. Details of these crack geometries and their dependencies are discussed.