Nickel und Nickel (II) -oxid werden in großem Umfang in fortgeschrittenen elektronischen Geräten verwendet. In der Mikroelektronik-Industrie wird Nickel verwendet werden, um Nickelsilizid bilden. Die Nickelmono Silizid (NiSi) wurde als ausgezeichnetes Material für Source-Drain-Kontaktanwendungen unter 45 nm-CMOS-Technologie entwickelt. Im Vergleich zu anderen Siliziden für die Kontaktanwendungen verwendet wird NiSi wegen seines niedrigen spezifischen Widerstand, niedrigen Kontaktwiderstand, relativ niedrigen Bildungstemperatur und niedrigem Siliziumverbrauchs bevorzugt. Nickel in Nickelbasis-Akkus und ferromagnetischen Direktzugriffsspeicher (RAMs) verwendet. Nickel (II) oxid wird als Transistor-Gate-Oxid und Oxid in resistive RAM genutzt wird. Atomic Layer Deposition (ALD) ist eine spezielle Art der Chemical Vapor Deposition (CVD), das verwendet wird, um sehr glatte sowie homogene Dünnfilme mit hervorragenden Treue auch bei hohen Seitenverhältnissen abzuscheiden. Es basiert auf selbstabschließenden sequentielle Gas-Feststoff-Reaktionen, die eine präzise Steuerung der Filmdicke auf wenige Angström lassen sich auf der Basis. Zur Herstellung der heutigen 3D-elektronische Geräte, sind Technologien wie ALD erforderlich. Trotz der Vielzahl von praktischen Anwendungen von Nickel und Nickel (II) -oxid, sind einige Nickelvorstufen zur thermischen basierend ALD erhältlich. Darüber hinaus haben diese Vorstufen bei schlechten Filmeigenschaften führte und die Prozesseigenschaften wurden ebenfalls begrenzt. Daher in dieser Masterarbeit mussten die Eigenschaften verschiedener neuartiger Nickelvorstufen zu bewerten. Alle neuen Vorstufen heteroleptische (verschiedene Arten von Liganden) und Komplexe wurden vom Hersteller speziell zur thermischen basierend ALD aus reinem Nickel mit H 2 als ein Co-Reaktionsmittel gestaltet. Um die neuartige Vorläufer zu untersuchen, wurde eine neue Methode entwickelt, um kleine Mengen in einer sehr zeitsparend (bis zu 2 g) von Ausgangsstoffen zu testen. Diese Methodologie beinhaltet: TGA / DTA-Kurve analysiert der Vorstufen, thermische Stabilitätstests in dem die Vorläufer (<0,1 g) wurden bei erhöhter Temperatur in einer abgedichteten Umgebung für mehrere Stunden wurde die Abscheidung Experimenten und Film Charakterisierungen erhitzt. Die Abscheidungen wurden mit Hilfe der in situ Quarzmikrowaage überwacht, während die anwendungsbezogenen Filmeigenschaften, wie chemische Zusammensetzung, physikalische Phase, Dicke, Dichte, Härte und Schichtwiderstand wurden mit Hilfe von ex situ Messverfahren untersucht. Vor der Evaluierung neuartiger Nickelvorstufen ein Benchmark ALD-Prozess war vom Referenznickelvorläufer (Ni (AMD)) und Luft als Reaktionspartner entwickelt. Das Hauptziel der Entwicklung und Optimierung von solchen Benchmark-ALD-Prozess war es, Standard-Prozessparameter wie zweite Reaktionspartner Belichtungszeiten, Argonspülung Zeiten, gesamtprozessdruck, beginnend Abscheidungstemperatur und Gasströme zu extrahieren. Diese Standard-Prozessparameter mussten verwendet, um die Prozessentwicklung Aufgabe (das spart Vorläufer Verbrauch) zu verkürzen und die Sublimationstemperatur Optimierung für jede neuartige Vorstufe werden. Die ALD Verhalten wurde in Bezug auf die Wachstumsrate durch Variation des Nickelvorläuferbelichtungszeit, Vorläufer Temperatur und Niederschlagstemperatur überprüft.:Lists of Abbreviations and Symbols VIII Lists of Figures and Tables XIV 1 Introduction 1 I Theoretical Part 3 2 Nickel and Nickel Oxides 4 2.1 Introduction and Existence 5 2.2 Material properties of Nickel and Nickel Oxide 5 2.3 Application in electronic industry 5 3 Atomic Layer Deposition 7 3.1 History 8 3.2 Definition 8 3.3 Features of thermal-ALD 8 3.3.1 ALD growth mechanism – an ideal view 8 3.3.2 ALD growth behaviour 10 3.3.3 Growth mode 11 3.3.4 ALD temperature window 11 3.4 Benefits and limitations 12 3.5 Precursor properties for thermal-ALD 13 3.6 ALD & CVD of Nickel – A literature survey 13 4 Metrology 17 4.1 Thermal analysis of precursors 18 4.2 Film and growth characterization 21 4.2.1 Quartz Crystal Microbalance 21 4.2.2 Spectroscopic Ellipsometry 24 4.2.3 X-Ray Photoelectron Spectroscopy 28 4.2.4 Scanning Electron Microscopy 29 4.2.5 X-Ray Reflectometry and X-Ray Diffraction 29 4.2.6 Four Point Probe Technique 20 5 Rapid Thermal Processing 32 5.1 Introduction 33 5.2 Basics of RTP 33 5.3 Nickel Silicides-A literature survey 33 II Experimental Part 36 6 Methodologies 37 6.1 Experimental setup 38 6.2 ALD process 41 6.2.1 ALD process types and substrate setups 41 6.2.2 Process parameters 41 6.3 Experimental procedure 42 6.3.1 Tool preparation 42 6.3.2 Thermal analysis and ALD experiments from nickel precursors 43 6.3.3 Data acquisition and evaluation 44 6.3.4 Characterization of film properties 46 7 Results and discussion 48 7.1 Introduction 49 7.2 QCM verification with Aluminum Oxide ALD process 49 7.3 ALD process from the reference precursor 50 7.3.1 Introduction 50 7.3.2 TG analysis for Ni(amd) precursor 51 7.3.3 Thermal stability test for Ni(amd) 51 7.3.4 ALD process optimization 52 7.3.5 Film properties 54 7.4 Evaluating the novel Nickel precursors 55 7.4.1 Screening tests for precursor P1 55 7.4.2 Screening tests for precursor P2 62 7.4.3 Screening tests for precursor P3 66 7.4.4 Screening tests for precursor P4 70 7.4.5 Screening tests for precursor P5 72 7.5 Comparison of all nickel precursors used in this work 74 8 Conclusions and outlook 77 References 83 III Appendix 101 A Deposition temperature control & Ellipsometry model 102 B Gas flow plan 105 / Nickel and nickel(II) oxide are widely used in advanced electronic devices . In microelectronic industry, nickel is used to form nickel silicide. The nickel mono-silicide (NiSi) has emerged as an excellent material of choice for source-drain contact applications below 45 nm node CMOS technology. As compared to other silicides used for the contact applications, NiSi is preferred because of its low resistivity, low contact resistance, relatively low formation temperature and low silicon consumption. Nickel is used in nickel-based rechargeable batteries and ferromagnetic random access memories (RAMs). Nickel(II) oxide is utilized as transistor gate-oxide and oxide in resistive RAMs. Atomic Layer Deposition (ALD) is a special type of Chemical Vapor Deposition (CVD) technique, that is used to deposit very smooth as well as homogeneous thin films with excellent conformality even at high aspect ratios. It is based on self-terminating sequential gas-solid reactions that allow a precise control of film thickness down to few Angstroms. In order to fabricate todays 3D electronic devices, technologies like ALD are required. In spite of huge number of practical applications of nickel and nickel(II) oxide, a few nickel precursors are available for thermal based ALD. Moreover, these precursors have resulted in poor film qualities and the process properties were also limited. Therefore in this master thesis, the properties of various novel nickel precursors had to be evaluated. All novel precursors are heteroleptic (different types of ligands) complexes and were specially designed by the manufacturer for thermal based ALD of pure nickel with H 2 as a co-reactant. In order to evaluate the novel precursors, a new methodology was designed to test small amounts (down to 2 g) of precursors in a very time efficient way. This methodology includes: TGA/DTA curve analyses of the precursors, thermal stability tests in which the precursors (< 0.1 g) were heated at elevated temperatures in a sealed environment for several hours, deposition experiments, and film characterizations. The depositions were monitored with the help of in situ quartz crystal microbalance, while application related film properties like chemical composition, physical phase, thickness, density, roughness and sheet resistance were investigated with the help of ex situ measurement techniques. Prior to the evaluation of novel nickel precursors, a benchmark ALD process was developed from the reference nickel precursor (Ni(amd)) and air as a co-reactant. The main goal of developing and optimizing such benchmark ALD process was to extract standard process parameters like second-reactant exposure times, Argon purge times, total process pressure, starting deposition temperature and gas flows. These standard process parameters had to be utilized to shorten the process development task (thus saving precursor consumption) and optimize the sublimation temperature for each novel precursor. The ALD behaviour was checked in terms of growth rate by varying the nickel precursor exposure time, precursor temperature and deposition temperature.:Lists of Abbreviations and Symbols VIII Lists of Figures and Tables XIV 1 Introduction 1 I Theoretical Part 3 2 Nickel and Nickel Oxides 4 2.1 Introduction and Existence 5 2.2 Material properties of Nickel and Nickel Oxide 5 2.3 Application in electronic industry 5 3 Atomic Layer Deposition 7 3.1 History 8 3.2 Definition 8 3.3 Features of thermal-ALD 8 3.3.1 ALD growth mechanism – an ideal view 8 3.3.2 ALD growth behaviour 10 3.3.3 Growth mode 11 3.3.4 ALD temperature window 11 3.4 Benefits and limitations 12 3.5 Precursor properties for thermal-ALD 13 3.6 ALD & CVD of Nickel – A literature survey 13 4 Metrology 17 4.1 Thermal analysis of precursors 18 4.2 Film and growth characterization 21 4.2.1 Quartz Crystal Microbalance 21 4.2.2 Spectroscopic Ellipsometry 24 4.2.3 X-Ray Photoelectron Spectroscopy 28 4.2.4 Scanning Electron Microscopy 29 4.2.5 X-Ray Reflectometry and X-Ray Diffraction 29 4.2.6 Four Point Probe Technique 20 5 Rapid Thermal Processing 32 5.1 Introduction 33 5.2 Basics of RTP 33 5.3 Nickel Silicides-A literature survey 33 II Experimental Part 36 6 Methodologies 37 6.1 Experimental setup 38 6.2 ALD process 41 6.2.1 ALD process types and substrate setups 41 6.2.2 Process parameters 41 6.3 Experimental procedure 42 6.3.1 Tool preparation 42 6.3.2 Thermal analysis and ALD experiments from nickel precursors 43 6.3.3 Data acquisition and evaluation 44 6.3.4 Characterization of film properties 46 7 Results and discussion 48 7.1 Introduction 49 7.2 QCM verification with Aluminum Oxide ALD process 49 7.3 ALD process from the reference precursor 50 7.3.1 Introduction 50 7.3.2 TG analysis for Ni(amd) precursor 51 7.3.3 Thermal stability test for Ni(amd) 51 7.3.4 ALD process optimization 52 7.3.5 Film properties 54 7.4 Evaluating the novel Nickel precursors 55 7.4.1 Screening tests for precursor P1 55 7.4.2 Screening tests for precursor P2 62 7.4.3 Screening tests for precursor P3 66 7.4.4 Screening tests for precursor P4 70 7.4.5 Screening tests for precursor P5 72 7.5 Comparison of all nickel precursors used in this work 74 8 Conclusions and outlook 77 References 83 III Appendix 101 A Deposition temperature control & Ellipsometry model 102 B Gas flow plan 105

Gasphasenabscheidungen werden zur Produktion dünner Schichten in der Mikro- und Nanoelektronik benutzt, um eine präzise Kontrolle der Schichtdicke im Sub-Nanometer-Bereich zu erreichen. Elektronische Eigenschaften der Schichten werden dabei von strukturellen Eigenschaften determiniert, deren Bestimmung mit hohem experimentellem Aufwand verbunden ist. Die vorliegende Arbeit erweitert ein hochparalleles Modell zur atomistischen Simulation des Wachstums und der Struktur von Dünnschichten, welches Molekulardynamik (MD) und Kinetic Monte Carlo-Methoden (KMC) kombiniert, um die Beschreibung beliebiger Gasphasenabscheidungen. KMC-Methoden erlauben dabei die effiziente Betrachtung der Größenordnung ganzer Nano-Bauelemente, während MD für atomistische Genauigkeit sorgt. Erste Ergebnisse zeigen, dass das Parsivald genannte Modell Abscheidungen in Simulationsräumen mit einer Breite von 0.1 µm x 0.1 µm effizient berechnet, aber auch bis zu 1 µm x 1 µm große Räume mit 1 Milliarden Atomen beschreiben kann. Somit lassen sich innerhalb weniger Tage Schichtabscheidungen mit einer Dicke von 100 Å simulieren. Die kristallinen und amorphen Schichten zeigen glatte Oberflächen, wobei auch mehrlagige Systeme auf die jeweilige Lagenrauheit untersucht werden. Die Struktur der Schicht wird hauptsächlich durch die verwendeten molekulardynamischen Kraftfelder bestimmt, wie Untersuchungen der physikalischen Gasphasenabscheidung von Gold, Kupfer, Silizium und einem Kupfer-Nickel-Multilagensystem zeigen. Stark strukturierte Substrate führen hingegen zu Artefakten in Form von Nanoporen und Hohlräumen aufgrund der verwendeten KMC-Methode. Zur Simulation von chemischen Gasphasenabscheidungen werden die Precursor-Reaktionen von Silan mit Sauerstoff sowie die Hydroxylierung von alpha-Al2O3 mit Wasser mit reaktiven Kraftfeldern (ReaxFF) berechnet, allerdings ist weitere Arbeit notwendig, um komplette Abscheidungen auf diese Weise zu simulieren. Mit Parsivald wird somit die Erweiterung einer Software präsentiert, die Gasphasenabscheidungen auf großen Substraten effizient simulieren kann, dabei aber auf passende molekulardynamische Kraftfelder angewiesen ist.

To increase the survival rate from infectious- and noncommunicable diseases, reliable diagnostic during the preliminary stages of a disease onset is of vital importance. This is not trivial to achieve, a highly sensitive and selective detection system is needed for measuring the low concentrations of biomarkers available. One possible route to achieve this is through biosensing based on plasmonic nanostructures, which during the last decade have demonstrated impressive diagnostic capabilities. These nanoplasmonic surfaces have the ability to significantly enhance fluorescence- and Raman signals through localized hotspots, where a stronger then normal electric field is present. By further utilizing a periodic sub-wavelength nanohole array the extraordinary optical transmission phenomena is supported, which open up new ways for miniaturization. In this study a nanoplasmonic chip (NPC) composed of a nanohole array —with lateral size on the order of hundreds of nanometer— covered in a thin layer of gold is created. The nanohole array is fabricated using soft nanoimprint lithography on two resists, hydroxypropyl cellulose (HPC) and polymethyl methacrylate (PMMA). An in depth analysis of the effect of thickness is done, where the transmittance and Raman scattering (using rhodamine 6G) are measured for varying gold layers from 5 to 21 nm. The thickness was proved to be of great importance for optimizing the Raman enhancement, where a maximum was found at 13 nm. The nanohole array were also in general found beneficial for additionally enhancing the Raman signal. A transmittance minima and maxima were found in the region 200-1000 nm for the NPCs, where the minima redshifted as the thickness increased. The extraordinary transmission phenomena was however not observed at these thin gold layers. Oxygen plasma treatment further proved an effective treatment method to reduce the hydrophobic properties of the NPCs. Care needs be taken when using thin layers of gold with a PMMA base, as the PMMA structure could get severely damaged by the plasma. HPC also proved inadequate for this projects purpose, as water-based fluids easily damaged the surface despite a deposited gold layer on top.

System on Chip (SoC) and System in Package (SiP) are two electronic technologies that involve integrating multiple functionalities onto a single platform. When the platform is a single wafer, as in SOC, it requires the ability to deposit various materials that enable the different functions on to an underlying substrate that can host the electronic circuitry. Transition metal oxides which have a wide range of properties are ideal candidates for the functional material. Si wafer on which micro-electronics technology is widely commercialized is the ideal host platform. Integrating oxides with Si, generally in the form of thin films as required by microelectronics technology, is however a challenge. It starts with the fact that the properties of crystalline oxides to be exploited in performing various functions are direction dependent. Thus, thin films of these oxides need to be deposited on Si in certain crystallographic orientations. Even if a suitably oriented Si wafer surface were available, it does not always provide for epitaxial growth a critical requirement for controlling the crystalline orientation of thin films. This is because Si surface is covered by an amorphous oxide of Si (SiOx). Thus, during growth of the functional oxide, an ambience in which the Si itself will not oxidize needs to be provided. In addition, during thin film growth on either Si or SiOx surface stresses are generated from various sources. Stress and its relaxation are also associated with the formation and evolution of defects. Both, stress and defects need to be managed in order to harness their beneficial effects and prevent detrimental ones. Given the requirement of SoC technology and the problem associated, the research work reported in this thesis was hence concerned with the precise controlling the stress and microstructure in oxide thin films deposited on Si substrates. In order to do so a versatile, ultra high vacuum (UHV) thin film with a base pressure of 10-9 Torr was designed and built as part of this study. The chamber is capable of depositing films by both sputtering (RF & DC) and pulsed laser ablation (PLD). The system has been designed to include an optical curvature measurement tool that enabled real-time stress measurement during growth. Doped zirconia, ZrO2, was chosen as the first oxide to be deposited, as it is among the few oxides that is more stable than SiOx. It is hence used as a buffer layer. It is shown in this thesis that a change in the growth rate at nucleation can lead to (100) or (111) textured films. These two are among the most commonly preferred orientation. Following nucleation a change in growth rate does not affect orientation but affects stress. Thus, independent selection of texture and stress is demonstrated in YSZ thin films on Si. A quantitative model based on the adatom motion on the growth surface and the anisotropic growth rates of the two orientations is used to explain these observations. This study was then subsequent extended to the growth on platinized Si another commonly used Si platform.. A knowledge of the stress and microstructure tailoring in cubic zirconia on Si was then extended to look at the effect of stress on electrical properties of zirconia on germanium for high-k dielectric applications. Ge channels are expected to play a key role in next generation n-MOS technology. Development of high-k dielectrics for channel control is hence essential. Interesting stress and property relations were analyzed in ZrO2/Ge. Stress and texture in pulsed laser deposited (PLD) oxides on silicon and SrTiO3 were studied. It is shown in this thesis that stress tuning is critical to achieve the highest possible dielectric constant. The effect of stress on dielectric constant is due to two reasons. The first one is an indirect effect involving the effect of stress on phase stability. The second one is the direct effect involving interatomic distance. By stress control an equivalent oxide thickness (EOT) of 0.8 nm was achieved in sputter deposited ZrO2/Ge films at 5 nm thickness. This is among the best reported till date. Finally, the effect of growth parameters and deposition geometry on the microstructural and stress evolution during deposition of SrTiO3 on Si and BaTiO3 on SrTiO3 by pulsed laser deposition is the same chamber is described.

Les matériaux moléculaires amorphes, aussi appelés verres moléculaires, sont constitués de molécules organiques de petite taille capables de s’organiser de façon désordonnée. En plus de présenter certaines des propriétés analogues à celles des polymères, ils offrent des avantages supplémentaires, puisqu’ils sont des espèces isomoléculaires dont la synthèse, la purification et la mise en œuvre sont facilitées par leur viscosité relativement faible. Toutefois, la préparation souvent exigeante de ces matériaux et leur durée de vie utile limitée par leur tendance à relaxer vers l’état cristallin demeurent des obstacles à leur utilisation pour certaines applications, e.g. opto-électronique, nanolithographie, pharmaceutique. Le développement de stratégies visant à faciliter la préparation de la phase vitreuse et éviter sa cristallisation est donc essentiel à la conception de matériaux moléculaires amorphes fonctionnels. L’objectif principal de cette thèse est d’établir des relations entre la structure moléculaire des verres moléculaires et leurs propriétés. Pour y arriver, différentes librairies de composés modèles, des dérivés analogues de triazine ayant démontré une excellente capacité à former une phase vitreuse, sont utilisées pour i) déterminer l’influence de la nature et de la position des groupements sur la triazine; ii) explorer l’influence des liaisons hydrogène sur les propriétés des verres lorsque leur structure comporte des groupements fonctionnels reconnus pour faciliter la cristallisation et lorsque leurs conditions de préparation se rapprochent de celles employées en industrie et iii) exploiter la phase amorphe afin d’étudier la photosensibilité des azobenzènes (azo) en vue d’optimiser leur utilisation dans des applications. Tout d’abord, l’influence des différents groupes substituants sur la triazine (groupements de tête, auxiliaires et liants) sur la capacité des composés à former une phase vitreuse (GFA), sur sa stabilité cinétique (GS) et sur sa température de transition vitreuse (Tg) est étudiée. Un système de classification des composés développé à partir de mesures de calorimétrie différentielle à balayage (DSC) et des mesures de spectroscopie infrarouge (IR) à température variable combinées à des analyses chimiométriques facilitent la rationalisation des rôles joués par chaque groupe. L’impact des liaisons hydrogène (H), de la barrière énergétique de rotation et de l’encombrement stérique des groupements est ainsi déterminé, permettant de conclure que le groupe de tête est le plus influent et que la présence de liaisons H n’est pas essentielle au GFA mais qu’elle est importante pour obtenir une Tg élevée. Ensuite, l’influence des liaisons H sur les propriétés des verres se rapprochant de ceux exploités dans l’industrie est explorée. Des mesures de spectroscopie IR à température variable, de DSC et de résolution de structures cristallines ont permis de conclure que les liaisons H réussissent à nuire à la cristallisation des composés et ce, même s’ils sont simultanément fonctionnalisés avec des motifs qui favorisent la cristallisation (empilements π-π entre dérivés stilbènes fluorés et non fluorés). De plus, trois composés analogues fonctionnalisés avec un groupement de tête possédant une capacité décroissante à établir des liaisons H (donneur, accepteur, aucune) ont été déposés en phase vapeur (PVD), une technique employée entre autres dans l’industrie opto-électronique pour évaluer leur capacité à former des verres ultrastables. Les films ainsi préparés présentent tous des propriétés similaires à celles des verres ultrastables précédemment étudiés, telles qu’une plus grande densité et anisotropie, et sont tous plus stables que ceux préparés par refroidissement à partir de l’état liquide. Toutefois, le verre formé du composé avec un groupement de tête donneur de liaisons H est moins stable que les autres d’au moins un ordre de grandeur, suggérant que les liaisons H limitent le niveau de stabilité atteignable par PVD. Finalement, un verre à base de triazine fonctionnalisé avec un groupement azo est employé pour étudier d’un point de vue moléculaire les perturbations provoquées par la photoisomérisation de l’azo. Grâce à une nouvelle méthode de spectroscopie IR, il est possible d’observer un gradient d’environnement moléculaire le long de la molécule lors de la photoisomérisation, permettant de soutenir certaines hypothèses relatives au déplacement macroscopique de la matière qui en résulte. Les mélanges de verres à base de triazine servent aussi de plateforme idéale pour découpler l’influence de la Tg et du contenu en azo sur la photo-orientation de l’azo, mais aussi sur la cinétique d’écriture et l’efficacité des réseaux de diffraction (SRG). Ce travail permet ainsi de déterminer une zone optimale de Tg pour l’inscription de SRG. Ces nouvelles connaissances mèneront à la conception plus rationnelle de nouveaux verres moléculaires, pouvant s’étendre à d’autres matériaux amorphes. / Amorphous molecular materials, also known as molecular glasses, are small organic molecules capable of being organized in a disordered manner. In addition to sharing some of the useful properties of polymers, they offer additional advantages because they are isomolecular species for which synthesis, purification and processing are facilitated by a relatively low viscosity. However, the usually demanding preparation conditions of these materials and their limited functional lifetime due to their tendency to relax to the crystalline state remain obstacles to their use for certain applications, e.g. opto-electronics, nanolithography, pharmaceuticals. The development of strategies to facilitate the preparation of the vitreous phase and avoid its crystallization is therefore essential for the design of functional amorphous molecular materials. The main objective of this thesis is to establish relationships between the molecular structure of molecular glasses and their properties. To achieve it, various libraries of model compounds, analogues of triazine derivatives that have demonstrated excellent glass-forming ability, are used to i) determine the influence of the nature and the position of the groups on the triazine; ii) explore the influence of hydrogen (H) bonds on the properties of glasses when their structure includes functional groups known to facilitate crystallization and when their preparation conditions are similar to those used in industry; and iii) exploit the amorphous phase in order to study the photoresponsiveness of azobenzenes (azo) in order to optimize their use in different applications. The influence of the various substituent groups on the triazine (headgroup, ancillary and linkers) on the glass-forming ability (GFA), the kinetic glass stability (GS) and the glass transition temperature (Tg) of the compounds is first studied. A classification system based on differential scanning calorimetry (DSC) and variable temperature infrared spectroscopy (IR) measurements combined to chemometrics analyses facilitate the rationalization of the roles played by each group. The impact of the H-bonds, the energy of the rotation barrier, and the steric hindrance of the groups is determined, leading to the conclusion that the headgroup is the most influential group and that the presence of H-bonds is not essential to the GFA, but important to obtain a high Tg. The influence of the H-bonds on the properties of glasses approaching those exploited in industry is then explored. Variable temperature IR spectroscopy measurements, DSC studies, and single crystal structure resolution have led to the conclusion that H-bonds impede the crystallization of the compounds even though they are simultaneously functionalized with moieties that promote crystallization (π-π stacking between fluorinated and non-fluorinated stilbene groups). In addition, three similar compounds functionalized with a headgroup presenting a decreasing capability to establish H-bonds (donor, acceptor, none) were vapor-deposited (PVD), a technique used, among others, in the opto-electronic industry, to evaluate their capability to form ultrastable glasses. These PVD glasses all show properties that are similar to those previously reported for ultrastable glasses, including higher density and anisotropy, and are all more kinetically stable than glasses prepared by cooling from the viscous state. However, the PVD glasses prepared with a H-bond donor headgroup are less stable than the others by at least an order of magnitude, suggesting that H-bonds limit the level of kinetic stability achievable by PVD. Finally, a triazine molecular glass functionalized with an azo group is used to study, from a molecular point of view, the perturbations caused by the photoisomerization of the azo. A new IR spectroscopy method was developed to observe a molecular environment gradient along the molecule during photoisomerization, making it possible to support certain hypotheses concerning the resulting macroscopic transport of the material. Triazine-based molecular glass blends are also used as an ideal platform for decoupling the influence of Tg and azo content on the azo photo-orientation, but also on the inscription kinetics and the diffraction efficiency of surface relief gratings (SRGs). This work enables the determination of an optimal Tg range for the inscription of SRGs. Altogether, these new insights will lead to a more rational design of new molecular glasses, which can extend to other amorphous molecular materials.

Currently conventional sources like coal, petroleum and natural gas meet the energy requirements of developing and undeveloped countries. Over a period of time there is high risk of these energy sources getting depleted. Hence an alternate source of energy i.e. renewable energy is the need of the hour. The advantages of renewable energy like higher sustainability, lesser maintenance, low cost of operation, and minimal impact on the environment make the role of renewable energy sources significant. Out of the various renewable energy sources like solar energy, wind energy, hydropower, biogas, tidal and geothermal, usage of solar energy is gradually increasing. Among various solar energy sources, Photovoltaics has dominated over the past two decades since it is free clean energy and availability of abundant sunlight on earth. Over the past few decades, thin film solar cells (TFSC) have gained considerable interest as an economically feasible alternative to conventional silicon (Si) photovoltaic devices. TFSCs have the potential to be as efficient as Si solar cells both in terms of conversion efficiency as well as cost. The advantages of TFSC are that they are easy to prepare, lesser thickness, requires lesser materials, light weight, low cost and opto-electronic properties can be tuned by varying the process parameters. The present study is focused on the fabrication of AgInS2/ZnS heterojunction thin film solar cell. AgInS2 absorber layer is deposited using both vacuum (sputtering/sulfurization) and non-vacuum (ultrasonic spray pyrolysis) techniques. ZnS window layer is prepared using thermal evaporation technique, detailed experimental investigation has been conducted and the results have been reported in this work. The thesis is divided into 6 chapters. Chapter 1 gives general introduction about solar cells and working principle of solar cell. It also discusses thin film solar cell technology and its advantages. Layers of thin film solar cell structure, Significance of each layers and possible materials to be used are emphasized. A detailed overview of the available literature on both AgInS2 absorber layer and ZnS window layer has been presented. Based on the literature review, objectives of the present work are defined. Chapter 2 explains the theory and experimental details of deposition techniques used for the growth of AgInS2 and ZnS films. Details of characterization techniques to study film properties are described in detail. Chapter 3 presents a systematic study of AgInS2 thin films deposited by sulfurization of sputtered Ag-In metallic precursors. Initially, AgInS2 films are deposited by varying the substrate temperature and properties of as-deposited films are characterized. Structural, morphological, electrical and optical properties of AgInS2 films are explained. From these studies, samples with better properties at particular substrate temperature are optimized. By fixing the substrate temperature, deposition time of silver is varied by keeping other deposition conditions same and the properties of films are discussed. It was observed that deposition time of silver doesn’t have much impact on structural properties of AgInS2 films. However, opto-electric properties of AgInS2 films are enhanced. Based on characterization studies, deposition time of silver is optimized. Deposition time of indium is varied by keeping substrate temperature and silver deposition to optimized value. The properties of as-deposited films are discussed. Based on the above studies, the optimized p type films have a band gap of 1.64 eV, carrier concentration of 1013 ions/cm3 and Resistivity of order 103 Ω-cm. Chapter 4 presents a systematic study of AgInS2 thin films deposited by ultrasonic spray pyrolysis. AgInS2 films are deposited by varying the substrate temperature and properties of as deposited films are characterized. Structural, morphological, electrical and optical properties of AgInS2 films are explained. From these studies, samples with better properties at particular substrate temperature are optimized. By fixing the substrate temperature, concentration of silver molarity in the precursor solution is varied by keeping other deposition conditions same and the properties of films are discussed. Structural, optical and electrical properties of AgInS2 films are enhanced with the increase in silver concentration. Based on characterization studies, concentration of silver is optimized. Similarly concentration of indium molarity in the precursor solution is varied and the properties of as-deposited films are discussed. Finally, sulfur molarity in the precursor solution is varied and properties of films are discussed. It was observed that increasing sulfur after certain limit does not have any effect on the properties of the films. Based on the above studies, this method resulted in the films with resistivity of 103 Ω-cm and band gap of 1.64 eV. These films showed a carrier concentration of 1013 ions/cm3. Chapter 5 describes the growth of ZnS films using thermal evaporation technique. Influence of thickness on the properties of ZnS films is explained. Samples with good crystallinity, high transmission, and wider gap are selected for device fabrication. This p type layer showed a band gap of 3.52 eV. Solar cells have been fabricated using the AgInS2 films developed by both sputtering and ultrasonic spray pyrolysis techniques. A maximum cell efficiency of 0.92 percent has been achieved for the cell with 0.950 µm thick sputtered AgInS2 layer and thermally evaporated 42 nm thick ZnS layer. In comparison, the ultrasonic spray pyrolysis deposited films gave an efficiency of 0.54 percent. These values are comparable to those mentioned in a couple of reports earlier. Chapter 6 summarizes the conclusions drawn from the present investigations and scope of future work is suggested.

Mit der vorliegenden Arbeit wird das Wachstum von polykristallinem Silicium auf Glas bei niedrigen Temperaturen aus metallischen Lösungen in einem Zweistufenprozess untersucht. Im ersten Prozessschritt werden nanokristalline Siliziumschichten (nc-Si) hergestellt, entweder durch die direkte Abscheidung auf geheizten Substraten oder durch als ''Amorphous-Liquid-Crystalline''(ALC)-Umwandlung bezeichnete metall-induzierte Kristallisation. Im zweiten Prozessschritt dienen die Saatschichten als Vorlage für das Wachstum von deutlich größeren Kristalliten durch stationäre Lösungszüchtung. Die ALC-Prozessdauer konnte durch umfassende Parameterstudien signifikant reduziert werden. Die Charakterisierung der durch direkte Abscheidung auf geheizten Substraten entstehenden nc-Si Saatschichten offenbarte, dass es sich dabei um individuelle Saatkörner handelt, die in eine quasi-amorphe Matrix eingebettet sind. Die Oxidation der Saatschichten vor dem zweiten Prozessschritt wurde als ein wesentliches Hindernis für das Wachstum identifiziert. Als erfolgreichste Lösung zur Überwindung dieses Problems hat sich ein anfänglicher Rücklöseschritt erwiesen. Da diese Methode jedoch schwierig zu kontrollieren ist, wurde ein UV-Laser-System entwickelt und installiert. Erste Resultate zeigen epitaktisches Wachstum an den Stellen, an denen das Oxid entfernt wurde. Bei der Lösungszüchtung auf ALC-Schichten beginnt das Wachstum an einigen größeren Saatkristallen, von wo aus umliegende Gebiete lateral überwachsen werden. Obwohl Kristallitgrößen bis zu 50 Mikrometern erreicht wurden, war es noch nicht möglich, geschlossene Schichten zu erzielen. Durch Lösungszüchtung auf nc-Si Saatschichten hingegen konnte dieses Ziel erreicht werden. Geschlossene, polykristalline Si-Schichten wurden erzeugt, auf denen alle Si-Kristallite miteinander verbunden sind. Neben den Wachstumsexperimenten wurden 3D-Simulationen durchgeführt, in denen u.a. unterschiedliche Heizerkonfigurationen simuliert wurden. / The subject of this thesis is the investigation of the growth of polycrystalline silicon on glass at low temperatures from metallic solutions in a two-step growth process. In the first process step, nanocrystalline Si (nc-Si) films are formed either by direct deposition on heated substrates, or by a metal-induced crystallization process, referred to as amorphous-liquid-crystalline (ALC) transition. In the second process step, these seed layers serve as templates for the growth of significantly larger Si crystallites by means of steady-state solution growth. Extensive parameter studies for the ALC process helped to bring down the process duration significantly. Characterization of the nc-Si seed layers, formed by direct deposition on heated substrates, showed that the layer is composed of individual seeds, embedded in a quasi-amorphous matrix. The oxidation of the seed layers prior to the second process step was found to be a major obstacle. The most successful solution has been an initial melt-back step. As the process is hard to control, though, a UV laser system has been developed and installed. First promising results show unobstructed epitaxial growth where the oxide has been removed. Steady-state solution growth on ALC seed layers was found to start from a few larger seed crystals, and then cover the surrounding areas by lateral overgrowth. Although crystallites with sizes of up to 50 micrometers were obtained, it was not yet possible to achieve full surface coverage with a continuous layer. By solution growth on nc-Si seed layers, however, it was eventually possible to achieve this goal. Continuous, polycrystalline Si layers were grown, on which all Si crystallites are interlocked. The growth experiments were accompanied by 3D simulations, in which e.g. different heater configurations have been simulated.

Gasphasenabscheidungen werden zur Produktion dünner Schichten in der Mikro- und Nanoelektronik benutzt, um eine präzise Kontrolle der Schichtdicke im Sub-Nanometer-Bereich zu erreichen. Elektronische Eigenschaften der Schichten werden dabei von strukturellen Eigenschaften determiniert, deren Bestimmung mit hohem experimentellem Aufwand verbunden ist. Die vorliegende Arbeit erweitert ein hochparalleles Modell zur atomistischen Simulation des Wachstums und der Struktur von Dünnschichten, welches Molekulardynamik (MD) und Kinetic Monte Carlo-Methoden (KMC) kombiniert, um die Beschreibung beliebiger Gasphasenabscheidungen. KMC-Methoden erlauben dabei die effiziente Betrachtung der Größenordnung ganzer Nano-Bauelemente, während MD für atomistische Genauigkeit sorgt. Erste Ergebnisse zeigen, dass das Parsivald genannte Modell Abscheidungen in Simulationsräumen mit einer Breite von 0.1 µm x 0.1 µm effizient berechnet, aber auch bis zu 1 µm x 1 µm große Räume mit 1 Milliarden Atomen beschreiben kann. Somit lassen sich innerhalb weniger Tage Schichtabscheidungen mit einer Dicke von 100 Å simulieren. Die kristallinen und amorphen Schichten zeigen glatte Oberflächen, wobei auch mehrlagige Systeme auf die jeweilige Lagenrauheit untersucht werden. Die Struktur der Schicht wird hauptsächlich durch die verwendeten molekulardynamischen Kraftfelder bestimmt, wie Untersuchungen der physikalischen Gasphasenabscheidung von Gold, Kupfer, Silizium und einem Kupfer-Nickel-Multilagensystem zeigen. Stark strukturierte Substrate führen hingegen zu Artefakten in Form von Nanoporen und Hohlräumen aufgrund der verwendeten KMC-Methode. Zur Simulation von chemischen Gasphasenabscheidungen werden die Precursor-Reaktionen von Silan mit Sauerstoff sowie die Hydroxylierung von alpha-Al2O3 mit Wasser mit reaktiven Kraftfeldern (ReaxFF) berechnet, allerdings ist weitere Arbeit notwendig, um komplette Abscheidungen auf diese Weise zu simulieren. Mit Parsivald wird somit die Erweiterung einer Software präsentiert, die Gasphasenabscheidungen auf großen Substraten effizient simulieren kann, dabei aber auf passende molekulardynamische Kraftfelder angewiesen ist.:Inhaltsverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Abkürzungsverzeichnis Symbolverzeichnis 1 Einleitung 2 Grundlagen 2.1 Gasphasenabscheidungen 2.1.1 Physikalische Gasphasenabscheidung 2.1.2 Chemische Gasphasenabscheidung 2.1.3 Atomlagenabscheidung 2.1.4 Methoden zur Simulation von Gasphasenabscheidungen 2.2 Molekulardynamik 2.2.1 Formulierung der Molekulardynamik 2.2.2 Auswahl verfügbarer Molekulardynamik-Software 2.2.3 Molekulardynamische Kraftfelder 2.3 Kinetic Monte Carlo-Methoden 2.4 Datenstrukturen 2.4.1 Numerische Voraussetzungen an Gasphasenabscheidungen 2.4.2 Vergleich der Laufzeiten für verschiedene Datenstrukturen 2.4.3 Effiziente Datenstrukturen 2.4.4 Alpha-Form 3 Methoden und Modelle 3.1 Stand der Forschung 3.1.1 Anwendungen von KMC-Simulationen für die Gasphasenabscheidung 3.1.2 Anwendung von MD-Simulationen für die Gasphasenabscheidung 3.2 Parsivald-Modell 3.2.1 Zielsetzung für Parsivald 3.2.2 Beschreibung des Parsivald-Modells 3.2.3 Annahmen und Einschränkungen 3.2.4 Erweiterungen im Rahmen der Masterarbeit 3.2.5 Behandlung von fehlerhaften Ereignissen 3.3 Laufzeitanalyse von Parsivald-Simulationen 3.3.1 Ereignis-Laufzeit TE 3.3.2 Ereignis-Durchsatz RE 3.3.3 MD-Laufzeit TMD 3.3.4 Worker-Laufzeit Tworker 3.3.5 Serielle Laufzeit T1 3.3.6 Anzahl der parallelen Prozesse p 3.3.7 Workerdichte rhoworker 3.3.8 Parallele Laufzeit Tp 3.3.9 Speedup Sp 3.3.10 Parallele Effizienz Ep 3.3.11 Auswertung der Laufzeitparameter 3.3.12 Fazit 3.4 MD-Simulationen: Methoden und Auswertungen 3.4.1 Zeitskalen in MD-Simulationen 3.4.2 Relaxierungen 3.4.3 Strukturanalysen 3.4.4 Bestimmung der Dichte und Temperatur 3.4.5 Radiale Verteilungsfunktionen, Bindungslänge und Koordinationszahl 3.4.6 Oberfläche, Schichtdicke, Rauheit und Porösität 3.4.7 Reaktionen und Stabilität von Molekülen 4 Simulationen von Gasphasenabscheidungen 4.1 Gold-PVD 4.1.1 Voruntersuchungen 4.1.2 Thermodynamische Eigenschaften 4.1.3 Simulation von Gold-PVD 4.1.4 Skalierbarkeit mit der Simulationsgröße 4.1.5 Fazit 4.2 Kupfer-PVD 4.2.1 Voruntersuchungen 4.2.2 Thermodynamische Eigenschaften 4.2.3 Simulation von Kupfer-PVD 4.2.4 Untersuchung der maximalen Workerdichte 4.2.5 Fazit 4.3 Multilagen-PVD 4.3.1 Multilagen-Simulationen mit Parsivald 4.3.2 Vergleich mit Ergebnissen reiner MD-Simulationen 4.3.3 Vergleich der Parallelisierbarkeit 4.3.4 Fazit 4.4 Silizium-PVD 4.4.1 Voruntersuchungen 4.4.2 Simulationen von Silizium-PVD 4.4.3 Fazit 4.5 Aluminiumoxid-ALD 4.5.1 ReaxFF-Parametersätze 4.5.2 Voruntersuchungen 4.5.3 Fazit 5 Zusammenfassung und Ausblick 5.1 Zusammenfassung 5.2 Ausblick A Physikalische Konstanten und Stoffeigenschaften B Datenstrukturen B.1 Übersicht über KMC-Operationen B.2 Beschreibung grundlegender Datenstrukturen B.3 Delaunay-Triangulationen B.3.1 Ausgewählte Eigenschaften einer Delaunay-Triangulation B.3.2 Algorithmen zur Konstruktion einer Delaunay-Triangulation C Ergänzungen zur Laufzeitanalyse von Parsivald C.1 Einfluss der Ereignis-Laufzeit auf die effiziente Raumgröße weff C.2 Zusätzliche Einflüsse auf das Maximum der Prozesse pmax C.3 Abschätzung der maximalen Workerdichte per Random Sequential Adsorption D Ergänzungen zur Simulation von Gold-PVD E Multilagen-PVD E.1 Porenbildung bei Unterrelaxation E.2 Simulationen mit Lagendicken von jeweils 5 nm F Simulation der CVD-Precursormoleküle Silan und Sauerstoff F.1 Stabilität der Precursormoleküle F.2 Reaktion der Precursormoleküle Literaturverzeichnis

Sélectionner des traitements de surface pour l’industrie nécessite de prendre en compte : les propriétés à conférer au substrat, la nature et la géométrie de celui-ci et les caractéristiques du milieu extérieur. Certaines combinaisons de ces paramètres rendent difficile la sélection d’un traitement unique, d’où le recours à des multitraitements de surface. Dès lors, se posent les questions suivantes : - Utiliser des multitraitements de surface peut se faire en scindant les différentes requêtes en sous-ensembles, de manière à ce que chaque traitement réponde à l’un d’eux. Dans quel ordre ces requêtes doivent-elles être introduites par rapport au substrat ? - Comment sélectionner les traitements de surface répondant à chaque requête individuelle ? - Comment classer des multitraitements en termes d’adéquation au problème posé ? Dans ce travail, les première et troisième questions sont abordées, en explorant les requêtes concernant habituellement les dispositifs de moulage de l’aluminium : - Résistance aux contraintes d’origine thermique. - Résistance à la corrosion par les métaux fondus. - Résistance au frottement. L’analyse de la bibliographie relative aux traitements de surface utilisés dans ces systèmes a été analysée et des « architectures »-types ont été identifiées (chapitre 3). On prévoit, par exemple, un traitement conférant la résistance à la fatigue superficielle, ainsi qu’un revêtement étanche et résistant à l’aluminium fondu. Une barrière thermique est parfois préconisée. Pour chacune des architectures, des traitements de surface individuels peuvent être sélectionnés. Un « facteur de performance » permettant de classer les solutions par rapport au problème de la fatigue thermique a été construit (chapitre 4) et discuté dans deux situations : - Lorsqu’un revêtement est présent, et que les contraintes d’origine thermique (différence de dilatation thermique couche-substrat) menacent de le rompre lors de l’immersion dans un milieu corrosif à haute température. Des essais de corrosion dans de l’aluminium fondu ont été réalisés sur un acier revêtu par du nitrure de chrome dopé à l’aluminium, synthétisé par déposition physique en phase vapeur (chapitre 5 – collaboration : Inasmet). - Lorsque des variations thermiques rapides menacent de rompre le substrat et la (les) couches. Des essais de fatigue thermique ont été réalisés sur de l’acier à outils pour travail à chaud non traité, boruré ou recouvert d’un multitraitements (zircone yttriée / NiCrAlY / boruration / acier). Le revêtement en zircone yttriée a été obtenu par projection par plasma. L’essai de fatigue thermique a été modélisé et le facteur de performance, discuté (chapitre 6). Au chapitre 7, les architectures-types ont été introduites dans une méthodologie de sélection des multi-traitements de surface, qui a été appliquée dans deux cas : - Celui des moules de fonderie, devant résister à la fatigue thermique et à la corrosion par l’aluminium fondu. Le facteur de performance a été extrapolé à d’autres situations qu’aux chapitres 5 et 6. Les solutions habituellement proposées pour résoudre ce problème sont retrouvées. - Celui de deux pièces en acier frottant l’une contre l’autre en présence d’aluminium fondu. To select surface treatments, one must account for the required functional properties, the substrate features and the solicitations the substrate must endure. Certain combinations of these parameters make it difficult to select a single surface treatment, a reason why several successive treatments are preferred. To select them, one needs to determine: - How to divide the several requests into groups and how to stack up these groups from the substrate to the outer surface, so that each treatment deals with one specific group of requests/properties. - How to select individual layers for each group of properties. - How to rank the multi-treatments in terms of relevance for a given application. In this work, one tries to answer the first and the third questions, by studying the case of aluminium foundry, in which the industrial devices frequently face the following solicitations: - Thermal stress (thermal fatigue, thermal expansion mismatch). - Presence of corrosive molten metal. - Sliding wear. In the literature, several “standard” architectures are proposed (chapter 3), like a diffusion layer reducing superficial fatigue plus a corrosion barrier layer. A thermal barrier coating is also sometimes proposed. For each of these architectures, one can select individual treatments. To rank them, one devised a “performance index” for thermal stress (chap.4), which is discussed for two cases: - For large differences between layer and substrate thermal expansion coefficients, when both are put into contact with a high temperature corrosive medium, the layer may be damaged. One discusses this case by examining the corrosion caused by molten aluminium for a steel substrate coated by anticorrosive chromium nitride doped with aluminium. The layer is produced by physical vapour deposition (chap. 5 – cooperation: Inasmet). - Repeated fast surface temperature transients can also damage the substrate and/or the layer by thermal fatigue. One conducted thermal fatigue tests with samples of hot work tool steel, respectively untreated, simply borided and protected by a multilayer. In the last case, top coat is yttria stabilised zirconia, followed by a nickel superalloy and then a borided layer (undercoat). One synthesized the zirconia coating by plasma spray and one modelled the thermal fatigue (chap. 6). In chap. 7, architectures from chap. 2 are introduced in a multi-treatment selection routine, which is applied in two cases: - Foundry moulds for molten aluminium, withstanding both thermal fatigue and corrosion. The devised performance index is extrapolated beyond the tests of chap. 5 and 6 to treatments for this industrial application, thereby quantifying their respective merits. - A foundry device exposed to molten metal and sliding wear.

Sélectionner des traitements de surface pour l’industrie nécessite de prendre en compte :les propriétés à conférer au substrat, la nature et la géométrie de celui-ci et les caractéristiques du milieu extérieur. Certaines combinaisons de ces paramètres rendent difficile la sélection d’un traitement unique, d’où le recours à des multitraitements de surface. Dès lors, se posent les questions suivantes :<p>- Utiliser des multitraitements de surface peut se faire en scindant les différentes requêtes en sous-ensembles, de manière à ce que chaque traitement réponde à l’un d’eux. Dans quel ordre ces requêtes doivent-elles être introduites par rapport au substrat ?<p>- Comment sélectionner les traitements de surface répondant à chaque requête individuelle ?<p>- Comment classer des multitraitements en termes d’adéquation au problème posé ?<p>Dans ce travail, les première et troisième questions sont abordées, en explorant les requêtes concernant habituellement les dispositifs de moulage de l’aluminium :<p>- Résistance aux contraintes d’origine thermique.<p>- Résistance à la corrosion par les métaux fondus.<p>- Résistance au frottement.<p>L’analyse de la bibliographie relative aux traitements de surface utilisés dans ces systèmes a été analysée et des « architectures »-types ont été identifiées (chapitre 3). On prévoit, par exemple, un traitement conférant la résistance à la fatigue superficielle, ainsi qu’un revêtement étanche et résistant à l’aluminium fondu. Une barrière thermique est parfois préconisée.<p>Pour chacune des architectures, des traitements de surface individuels peuvent être sélectionnés. Un « facteur de performance » permettant de classer les solutions par rapport au problème de la fatigue thermique a été construit (chapitre 4) et discuté dans deux situations :<p>- Lorsqu’un revêtement est présent, et que les contraintes d’origine thermique (différence de dilatation thermique couche-substrat) menacent de le rompre lors de l’immersion dans un milieu corrosif à haute température. Des essais de corrosion dans de l’aluminium fondu ont été réalisés sur un acier revêtu par du nitrure de chrome dopé à l’aluminium, synthétisé par déposition physique en phase vapeur (chapitre 5 – collaboration :Inasmet).<p>- Lorsque des variations thermiques rapides menacent de rompre le substrat et la (les) couches. Des essais de fatigue thermique ont été réalisés sur de l’acier à outils pour travail à chaud non traité, boruré ou recouvert d’un multitraitements (zircone yttriée / NiCrAlY / boruration / acier). Le revêtement en zircone yttriée a été obtenu par projection par plasma. L’essai de fatigue thermique a été modélisé et le facteur de performance, discuté (chapitre 6).<p>Au chapitre 7, les architectures-types ont été introduites dans une méthodologie de sélection des multi-traitements de surface, qui a été appliquée dans deux cas :<p>- Celui des moules de fonderie, devant résister à la fatigue thermique et à la corrosion par l’aluminium fondu. Le facteur de performance a été extrapolé à d’autres situations qu’aux chapitres 5 et 6. Les solutions habituellement proposées pour résoudre ce problème sont retrouvées.<p>- Celui de deux pièces en acier frottant l’une contre l’autre en présence d’aluminium fondu.<p><p>To select surface treatments, one must account for the required functional properties, the substrate features and the solicitations the substrate must endure. Certain combinations of these parameters make it difficult to select a single surface treatment, a reason why several successive treatments are preferred. To select them, one needs to determine:<p>- How to divide the several requests into groups and how to stack up these groups from the substrate to the outer surface, so that each treatment deals with one specific group of requests/properties.<p>- How to select individual layers for each group of properties.<p>- How to rank the multi-treatments in terms of relevance for a given application.<p>In this work, one tries to answer the first and the third questions, by studying the case of aluminium foundry, in which the industrial devices frequently face the following solicitations:<p>- Thermal stress (thermal fatigue, thermal expansion mismatch).<p>- Presence of corrosive molten metal.<p>- Sliding wear.<p>In the literature, several “standard” architectures are proposed (chapter 3), like a diffusion layer reducing superficial fatigue plus a corrosion barrier layer. A thermal barrier coating is also sometimes proposed.<p>For each of these architectures, one can select individual treatments. To rank them, one devised a “performance index” for thermal stress (chap.4), which is discussed for two cases:<p>- For large differences between layer and substrate thermal expansion coefficients, when both are put into contact with a high temperature corrosive medium, the layer may be damaged. One discusses this case by examining the corrosion caused by molten aluminium for a steel substrate coated by anticorrosive chromium nitride doped with aluminium. The layer is produced by physical vapour deposition (chap. 5 – cooperation: Inasmet).<p>- Repeated fast surface temperature transients can also damage the substrate and/or the layer by thermal fatigue. One conducted thermal fatigue tests with samples of hot work tool steel, respectively untreated, simply borided and protected by a multilayer. In the last case, top coat is yttria stabilised zirconia, followed by a nickel superalloy and then a borided layer (undercoat). One synthesized the zirconia coating by plasma spray and one modelled the thermal fatigue (chap. 6).<p>In chap. 7, architectures from chap. 2 are introduced in a multi-treatment selection routine, which is applied in two cases:<p>- Foundry moulds for molten aluminium, withstanding both thermal fatigue and corrosion. The devised performance index is extrapolated beyond the tests of chap. 5 and 6 to treatments for this industrial application, thereby quantifying their respective merits.<p>- A foundry device exposed to molten metal and sliding wear.<p><p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished