Neste trabalho foram realizadas algumas deposições de filmes de Nitreto de Titânio sobre substrato de aço inoxidável. Foi utilizado o processo conhecido como triodo magnetron sputtering. Os parâmetros de deposição foram mantidos entre as deposições, exceto pela voltagem de bias no substrato, que foi variada de uma deposição para outra. Medições in-situ das tensões residuais no filme depositado foram realizadas. As medições foram feitas através do método da curvatura do substrato, utilizando-se um sensor capacitivo posicionado dentro da câmara de deposição. Embora o dispositivo não tenha sido capaz de quantificar os valores de tensão, foi possível identificar a natureza das mesmas, indicando se elas são de caráter trativo ou compressivo. Comprovou-se a possibilidade do uso de sistemas capacitivos para medições em sputtering. Observou-se que os filmes depositados apresentaram tensões de caráter trativo durante as deposições. / In this work, a series of depositions of titanium nitride thin films was conducted in a triode unbalanced magnetron sputtering chamber. Similar parameters were selected during each deposition, except for the substrate bias voltage, which was different for every deposition. An in-situ measurement of film residual stresses was carried out as the depositions proceeded. This measurement was based on substrate curvature, which was assessed by a home-built capacitive sensor positioned inside the sputtering chamber. Although the measurement device was not able to quantify the stress values, it was possible to identify if they were tensile or compressive. It was proved the possibility of using capacitive measurement devices in sputtering processes. It was possible to observe that the films underwent tensile stresses during the deposition.

The broad theme of the present research investigation is Ion Assisted Deposition of thin films and its effect on the properties of thin films. Though this activity has been of interest to researchers for more than a decade, the development of different types of ion sources with control over the ion flux and energy, makes it a current topic of interest. Ion assisted deposition was successful in depositing thin films of many material with desired qualities, however, there are certain class of materials whose deposition has been rather difficult. This has mainly been attributed to higher energies and low ion flux of conventional ion sources. The advent of ECR ion sources for thin film deposition has given impetus to the deposition of such materials. This is due to the low energy high-density plasma generated in this type of sources. Hitherto, these sources were widely used in PECVD techniques and only recently the importance of ECR sources in PVD techniques has been realized. This thesis is on the development of ECR plasma source for ion assisted deposition of thin films using PVD techniques. This thesis is organized into six chapters. The first chapter gives an introduction on the ion assisted growth of thin films and the importance of ECR plasma. A detailed discussion on various aspects of ECR sources has been included. The design details on the development of ECR source have been discussed in the second chapter. The performance of ECR source as analyzed by the Langmuir probe are also discussed. Variation of plasma parameters like ion density, electron temperature, plasma potential and floating potential as a function of pressure and microwave power have been studied using Langmuir probe analysis. An ion density of the order of 1011/cm3 was measured at a distance of 8 cm from the plasma source with a microwave power of 400 watts. This was comparable to the ion density reported in downstream plasma of ECR sources. The behavior of plasma parameters with variation in microwave power and pressure was explained on the basis of microwave transmission above critical ion density and the microwave power absorption. The uniformity of the plasma parameters at the substrate position (29 cm from the ECR source) was found to be ± 2% over a diameter of 12 cm, which makes the ion source suitable for ion assisted deposition. The third chapter deals with the simulation and experimental study of the ECR sputtering process. ECR sputter type sources are equipped with cylindrical targets. The sputtered flux distribution on the substrate depends on target geometry, sputtering pressure and target-substrate distance. The effect of cylindrical geometry on the distribution of sputtered flux has been simulated by Monte Carlo methods. It is found that the sputtered flux distribution at different pressures and target-substrate distances in ECR sputter type source differs from the conventional glow discharge sputtering system equipped with planar targets. The simulated results are compared with the experimental results. The simulated data agree very well with the experimental data. The deposition and characterization of the TiN thin films for diffusion barrier applications in copper metallization have been discussed in the fourth chapter. Titanium nitride films are prepared by ECR sputtering. The effect of high density ion bombardment on the morphology, orientation and resistivity of the films was studied. It was observed that films with atomic smoothness could be prepared by ECR sputtering. Also the high density ion bombardment has been found to be effective for the film growth in (100) orientation. The behavior of TiN films deposited by this method as a diffusion barrier in copper metallization has been investigated. The resistivity measurements and RBS depth profile studies showed that up to 700°C there is no diffusion of copper into silicon. This shows that ECR sputtered TiN can be used as an effective diffusion barrier in copper metallization. The fifth chapter contains investigations on the ECR assisted growth of silicon nitride films. The films are characterized for composition, morphology and chemical bonding using AES, RBS, AFM, XPS and FTIR. AFM studies revealed that ion bombardment results in the reduction of surface roughness, which indicates dense film growth. The effect of ion assistance on the optical and electrical properties is studied in detail. Films prepared with microwave power ranging from 100 to 200 watts are having bandgap and refractive index of 4.9 eV and 1.92 respectively. Interface state density of silicon nitride films prepared in the above mentioned range was found to be 5x10 10 eVcm2. These films exhibited a resistivity of 10 13 Ω, cm and critical field of 4 MV/cm. The electrical conductivity in these films has been explained on the basis of Poole and Frenkel conduction. The low value of interface state density, higher resistivity, and critical field show that good quality SiN4 films can be deposited with low energy high density ECR plasma. A detailed summary of this research investigation has been discussed in the last chapter. The thesis is concluded with a discussion on the need of focused ECR source to establish ECR assisted deposition as a versatile technique for the growth of thin films.

Mit zunehmender Miniaturisierung mikroelektronischer Bauelemente steigen die Anforderungen an reproduzierbare qualitätskonforme Schichten. Um die zur Herstellung notwendigen ALD/PVD/CVD-Schichtabscheideanlagen in einen zuverlässigen Zustand zu versetzen, ist eine regelmäßige Kammerreinigung notwendig. Während des Abscheideprozesses werden nicht nur das Substrat, sondern auch die umliegenden Kammerteile beschichtet. Diese Schichten wachsen mit jedem Beschichtungszyklus weiter an. Der Stress zwischen Schicht und Kammerwand steigt beständig, und es besteht das Risiko das Teile abplatzen und auf die Waferoberfläche fallen und damit die Struktur unbrauchbar machen. Um das zu verhindern, muss die Kammerwand in einen regelmäßigen Zustand versetzt werden, in dem sichergestellt ist, daß keine Schichtreste abplatzen können. In der vorliegenden Arbeit wird ein neues Verfahren zur Trockenreinigung von ALD-Titannitrid Kammern vorgestellt. Dazu wurden TiN-Stücke (hergestellt im ALD, CVD, PVD-Verfahren) auf einem temperaturgeregelten Probenhalter platziert. Eine Argon/NF3 Gasmischung wurde in einer externen Plasmaquelle (RPS) zerlegt und in die Reaktionskammer geschleust. Die Ätzung wurde mit in-situ Reflexionsmessung beobachtet. Experimente mit Chlorzugabe wurden unternommen und ein starker Einfluss auf den Ätzmechanismus beobachtet. Die Ätzraten des TiN sind exponentiell abhängig von der Temperatur und proportional abhängig von der Verfügbarkeit atomaren Fluors. Dieses wird bei der Zerlegung von NF3 frei gesetzt und steht der Reaktion zur Verfügung. Die NF3-Zerlegung in Fluor und Stickstoff wurde mit Hilfe der Massenspektrometrie (QMS) untersucht, Zerlegungsgrade größer 96% wurden erreicht. Mit Hilfe dieser Messung kann der Einfluss der Kammerreinigung auf den Treibhausgasausstoß (GWP) bestimmt werden. Mit dem Ar/NF3-Verfahren können die GWP-Emissionen um 90% im Vergleich zur RIE-Ätzung mit SF6 reduziert werden. Mit Argon/Chlor-Plasmen konnte kein Titannitrid geätzt werden, da die physikalische Sputterkomponente fehlte. Durch Hinzufügen von Chlor zu einer Ar/NF3-Gasmischung konnte die Ätzrate um bis zu 270% im Bereich niedrige Temperaturen/niedriger Druck gesteigert werden. Bei höheren Temperaturen/höherem Druck fielen die Ar/NF3/Chlor Ätzraten allerdings deutlich hinter die des Ar/NF3 zurück. Die dazu führenden Effekte werden untersucht und ausgeführt. Die Nutzung von externen Plasmaquellen bietet eine vielversprechende Alternative um Abscheideanlagen von TiN-Rückständen reinigen zu können. Bei hohen Temperaturen werden deutlich höhere Ätzraten als bei anderen Schichten (SiN, SiO2, W) erreicht. Für Anwendungen im niedrigen Temperaturbereich erlaubt die Zugabe von Chlor interessante Anwendungsmöglichkeiten. / Demands on state of the art deposition technologies for semiconductor production focus on uniformity, repeatability and low defectivity. The chamber condition is a key parameter to achieve these high demands in chemical vapour deposition (CVD) processes and are even more critical to the atomic layer deposition processes (ALD). During the deposition process not only the wafer surface but other chamber parts as well are covered with a thin film. This film accumulates during the deposition cycles and is prone to fall off the walls and pollute the wafer surface. The chamber parts that are exposed to the deposition must be set back to a steady state so that no deposits fall off the walls. The chamber condition also changes uncontrolled with varying film condition on the wall. A new approach for cleaning of ALD-titanium nitride (TiN) deposition chambers was investigated. To determine etch rates TiN-samples (created by ALD, CVD and PVD) were placed on a temperature controlled sample holder. An argon/NF3 mixture was excited in an upstream remote plasma source (RPS) and then routed through the reaction chamber. No further plasma activation inside the reaction chamber was done. The etching was monitored by in-situ reflectometry and etch rates were calculated. The effect of chlorine addition was also studied and strong influence on etch rates was found. The etch rate of TiN is dependent exponentially on temperature and very low etch rates were achieved below 70◦C at a chamber pressure ranging from 20-300 Pa. It was found that this correlates very well with the vapour pressure of the reaction product TiF4. At temperatures of 300◦C etch rates up to 800 nm/min were achieved. The optimum pressure for etching was found at 100 Pa while the pressure effect was small. The etch rate was mainly dependent on the availability of activated fluorine to create TiF4 by the reaction 2 NF3 → N2 + 6 F* 2 TiN + 8 F* → 2 TiF4 + N2 The NF3 decomposition to nitrogen and fluorine was monitored by quadrupole mass spectrometry (QMS) and was found to be greater than 96%. This figure allows an estimation of the amount of Global warm potential (GWP) gas emmited by the process for environmental considerations. Using argon/NF3 or argon/fluorine mixtures in RPS devices reduces the GWP emissions by more than 90% compared to RIE plasma cleaning with SF6. No etching occurred by using argon/chlorine only mixtures as no physical etch component was involved in RPS etch. However adding chlorine to the argon/NF3 mixture accelerated the etching process. Chlorine addition to the argon/NF3 mixture increased the etch rates up to 270% in the low pressure/low temperature regime. At higher temperatures or higher pressures the etch rates dropped below the etch rates achieved solely with fluorine chemistry. It must be emphasized that there is no physical acceleration of the ionized molecules toward the etched sample in this remote plasma setup. The usage of a remote plasma offers an alternative way to remove residues from chambers running TiN deposition processes. At high temperatures the Ar/NF3 offers remarkably high etching rates for TiN compared to other films (silicon nitride, -oxide, tungsten) usually cleaned by remote plasma. For low temperature applications the chlorine enhancement offers an interesting alternative to accelerate the etch process.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-12T21:33:19Z No. of bitstreams: 1 LEOPOLDO VIANA BATISTA NETO - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2575700 bytes, checksum: a10f0685285492d2302637ed070d9631 (MD5) / Made available in DSpace on 2018-04-12T21:33:19Z (GMT). No. of bitstreams: 1 LEOPOLDO VIANA BATISTA NETO - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2575700 bytes, checksum: a10f0685285492d2302637ed070d9631 (MD5) Previous issue date: 2014-08-28 / Filmes finos de Nitreto de titânio (TiN) e Nitreto de titânio-zircônio (TiZrN) foram depositados sobre substratos de aço inoxidável 316 usando o método de Sputtering RF para deposição dos filmes. O planejamento de experimentos (DOE) tem sido reconhecido como um método poderoso para otimizar um processo complexo na indústria. Os efeitos do presente estudo foram verificar a viabilidade e confiabilidade da aplicação do método DOE em processos de Sputtering RF, otimizar os parâmetros de processamento para o processo de deposição, identificando os parâmetros sensíveis que afetam a espessura da camada depositada (E.C.D) e a resistência à corrosão (Ecorr.). Para o método de Sputtering RF, dois parâmetros, a taxa e tempo de deposição foram escolhidos para serem os parâmetros do processo. Depois da deposição, a estrutura de camada depositada foi caracterizada por Difração de Raios X (DRX) e por Microscopia Eletrônica de Varredura (MEV). Após o ensaio de polarização, a corrosão foi realizada a fim de investigar a relação entre o início da corrosão e a espessura da camada depositada. A análise de variância (ANOVA) foi realizada para avaliar os parâmetros sensíveis e prever as condições ideais. Com base na análise estatística, os parâmetros mais sensíveis no processo de Sputtering RF foram tanto a taxa como o tempo de deposição do filme fino. As melhores condições de deposição foram a taxa de deposição máxima e tempo máximo. / Titanium nitride (TiN) and titanium-zirconium nitride (TiZrN) thin films were deposited on ASTM F 138 stainless steel substrates using de Sputtering RF methods. Design of experiment (DOE) has long been recognized as a powerful method to optimize a complex process in industry. The purposes of present study were to verify the feasibility and reliability of the application of DOE method on de Sputtering RF processes and optimize the processing parameters for the deposition process, in which the sensitive parameters that affected the film properties were also identified. For de Sputtering RF method, two parameters, deposition rate and time were chosen to be the operating parameters. After deposition, the thin film structure was characterized by X-ray diffraction (XRD), and high-resolution scanning electron microscopy (SEM). After the polarization test, the corrosion analysis was carried out in order to investigate the relationship between the corrosion initiation and the thickness of the deposited layer. The analysis of variance (ANOVA) was conducted to assess the sensitive parameters and predict the optimum conditions. Based on the statistical analysis, the most sensitive parameters in de Sputtering RF process were both the deposition rate and time. The optimum deposition conditions in each system were maximum deposition rate and time.

Depuis 10 ans, les détecteurs à inductance cinétique (Kinetic Inductance Detector KID) ont connu un essor considérable dans le domaine de la radioastronomie millimétrique pour atteindre des limites de sensibilités de l'ordre du bruit de photon. Le détecteur à inductance cinétique est un résonateur, équivalent à un circuit RLC dont la fréquence de résonance est f_0, lithographié dans un métal supraconducteur. Des photons incidents, possédant une énergie plus grande que le gap supraconducteur, sont absorbés dans le matériau et modifient son impédance de surface résultant en un décalage Df_0 de la fréquence de résonance du résonateur. Plusieurs centaines de résonateurs, de fréquence de résonance distincte, sont organisés en matrice. Nous étudions la réalisation de matrices de détecteurs en aluminium contenant jusqu'à 1932 pixels sur des substrats de diamètre 100 mm sur lesquels les propriétés physiques du matériau supraconducteur sont très homogènes. Différentes approches permettant l'optimisation électrique et optique de ces matrices sont proposées. Ces optimisations ont permis de sélectionner des matrices de détecteurs répondant aux caractéristiques requises par l'IRAM et qui sont à présent installées dans l'instrument NIKA-2 (New Instrument of KID Array) au télescope de 30 m sur le Pico Veleta en Espagne. Nous analysons également la déposition par pulvérisation réactive de films fin de nitrure de titane et nous présentons une méthode rapide et non destructive de caractérisation de la teneur en azote dans ces films par ellipsométrie. Nous décrivons des détails sur l'amélioration du bâti de déposition pour produire des films de TiN plus homogènes en teneur d'azote. Des matrices de détecteurs en nitrure de titane sont fabriquées et caractérisées à partir de ces films. Les performances de cette première matrice sont prometteuses et nous encouragent à poursuivre leur développement. / For 10 years, kinetic inductance detectors are developed for millimeter radioastronomy and they now reach photon-noise sensitivities. A kinetic inductance detector (KID) is a resonator, equivalent to an RLC circuit whose resonant frequency is f_0, structured in a superconducting metal. Incoming photons, with energy greater than the superconducting gap, are absorbed in the metal and change its surface impedance leading to a shift Df_0 of the resonant frequency of the resonator. KID arrays are made with hundred of resonators with different resonant frequencies. We study the fabrication of aluminum-KID arrays of 1932 pixels on 4 inch substrate with homogeneous superconducting properties over this area. Various ways to electrically and optically optimize these arrays are proposed. These optimization allow us to choose arrays that have the required performances. These arrays are now installed in the NIKA-2 (New Instrument of KID Array) instrument in IRAM's 30 m telescope located on the Pico Veleta in Spain. We also analyze reactive sputtered titanium nitride thin films and we present a rapid and non-destructive measurement to characterize the nitrogen content in these films. We describe upgrades of the deposition chamber that allow more uniform thin films to be deposited. TiN KID arrays are fabricated and characterized from these optimized thin films. The performances of these TiN prototype arrays are surprisingly good and encourage future work.

Neste trabalho foram realizadas algumas deposições de filmes de Nitreto de Titânio sobre substrato de aço inoxidável. Foi utilizado o processo conhecido como triodo magnetron sputtering. Os parâmetros de deposição foram mantidos entre as deposições, exceto pela voltagem de bias no substrato, que foi variada de uma deposição para outra. Medições in-situ das tensões residuais no filme depositado foram realizadas. As medições foram feitas através do método da curvatura do substrato, utilizando-se um sensor capacitivo posicionado dentro da câmara de deposição. Embora o dispositivo não tenha sido capaz de quantificar os valores de tensão, foi possível identificar a natureza das mesmas, indicando se elas são de caráter trativo ou compressivo. Comprovou-se a possibilidade do uso de sistemas capacitivos para medições em sputtering. Observou-se que os filmes depositados apresentaram tensões de caráter trativo durante as deposições. / In this work, a series of depositions of titanium nitride thin films was conducted in a triode unbalanced magnetron sputtering chamber. Similar parameters were selected during each deposition, except for the substrate bias voltage, which was different for every deposition. An in-situ measurement of film residual stresses was carried out as the depositions proceeded. This measurement was based on substrate curvature, which was assessed by a home-built capacitive sensor positioned inside the sputtering chamber. Although the measurement device was not able to quantify the stress values, it was possible to identify if they were tensile or compressive. It was proved the possibility of using capacitive measurement devices in sputtering processes. It was possible to observe that the films underwent tensile stresses during the deposition.

<p> Optical metamaterials have triggered extensive studies driven by their fascinating electromagnetic properties that are not observed in natural materials. Aside from the extraordinary progress, challenges remain in scalable processing and material performance which limit the adoption of metamaterial towards practical applications. The goal of this dissertation is to design and fabricate nanocomposite thin films by combining nitrides with a tunable secondary phase to realize controllable multi-functionalities towards potential device applications. Transition metal nitrides are selected for this study due to the inherit material durability and low-loss plasmonic properties that offer stable two-phase hybridization for potential high temperature optical applications. Using a pulsed laser deposition technique, the nitride-metal nanocomposites are self-assembled into various geometries including pillar-in-matrix, embedded nanoinclusions or complex multilayers, that possess large surface coverage, high epitaxial quality, and sharp phase boundary. The nanostructures can be further engineered upon precise control of growth parameters. </p><p> This dissertation is composed of a general review of related background and experimental approaches, followed by four chapters of detailed research chapters. The first two research chapters involve hybrid metal (Au, Ag) - titanium nitride (TiN) nanocomposite thin films where the metal phase is self-assembled into sub-20 nm nanopillars and further tailored in terms of packing density and tilting angles. The tuning of plasmonic resonance and dielectric constant have been achieved by changing the concentration of Au nanopillars, or the tuning of optical anisotropy and angular selectivity by changing the tilting angle of Ag nanopillars. Towards applications, the protruded Au nanopillars are demonstrated to be highly functional for chemical bonding detection or surface enhanced sensing, whereas the embedded Ag nanopillars exhibit enhanced thermal and mechanical stabilities that are promising for high temperature plasmonic applications. In the last two chapters, dissimilar materials candidates beyond plasmonics have been incorporated to extend the electromagnetic properties, include coupling metal nanoinclusions into a wide bandgap semiconducting aluminum nitride matrix, as well as inserting a dielectric spacer between the hybrid plasmonic claddings for geometrical tuning and electric field enhancement. As a summary, these studies present approaches in addressing material and fabrication challenges in the field of plasmonic metamaterials from fundamental materials perspective. As demonstrated in the following chapters, these hybrid plasmonic nanocomposites provide multiple advantages towards tunable optical or biomedical sensing, high temperature plasmonics, controllable metadevices or nanophotonic chips.</p><div><br></div>

<p>One of the longstanding goals of photonics research has been to obtain strong optical nonlinearities. A promising method to achieve this goal is to operate in the so-called epsilon near zero (ENZ) spectral regime, where the real part of the dielectric permittivity changes sign. If accompanied by low losses, this region enables a platform to achieve extraordinarily high nonlinear response, along with many other interesting optical phenomena. In this work, some of the common all-optical switching structures employing homogeneous ENZ materials are investigated under varying conditions of frequency, incidence angle, and polarization. The optimum switching conditions have been highlighted to pave the way forward to the best experimental configurations in future studies. Moreover, the properties of some of the emerging novel plasmonic materials such as aluminum-doped zinc oxide (AZO) and titanium nitride (TiN) are investigated, specifically for ENZ applications. Their thickness-dependent crystalline structure and carrier densities are employed as a method to control their optical properties. A near-perfect absorption scheme is demonstrated utilizing the Ferrell-Berreman mode occurring at the ENZ region of ultrathin AZO and TiN film. The ENZ frequency and the associated absorption peak of AZO are engineered through thickness-dependence to cover most of the telecom range. This work covers the theoretical background for ENZ nonlinearities and looks into the materials aspect for better control of nonlinearities in experimental realizations.</p>

Mit zunehmender Miniaturisierung mikroelektronischer Bauelemente steigen die Anforderungen an reproduzierbare qualitätskonforme Schichten. Um die zur Herstellung notwendigen ALD/PVD/CVD-Schichtabscheideanlagen in einen zuverlässigen Zustand zu versetzen, ist eine regelmäßige Kammerreinigung notwendig. Während des Abscheideprozesses werden nicht nur das Substrat, sondern auch die umliegenden Kammerteile beschichtet. Diese Schichten wachsen mit jedem Beschichtungszyklus weiter an. Der Stress zwischen Schicht und Kammerwand steigt beständig, und es besteht das Risiko das Teile abplatzen und auf die Waferoberfläche fallen und damit die Struktur unbrauchbar machen. Um das zu verhindern, muss die Kammerwand in einen regelmäßigen Zustand versetzt werden, in dem sichergestellt ist, daß keine Schichtreste abplatzen können. In der vorliegenden Arbeit wird ein neues Verfahren zur Trockenreinigung von ALD-Titannitrid Kammern vorgestellt. Dazu wurden TiN-Stücke (hergestellt im ALD, CVD, PVD-Verfahren) auf einem temperaturgeregelten Probenhalter platziert. Eine Argon/NF3 Gasmischung wurde in einer externen Plasmaquelle (RPS) zerlegt und in die Reaktionskammer geschleust. Die Ätzung wurde mit in-situ Reflexionsmessung beobachtet. Experimente mit Chlorzugabe wurden unternommen und ein starker Einfluss auf den Ätzmechanismus beobachtet. Die Ätzraten des TiN sind exponentiell abhängig von der Temperatur und proportional abhängig von der Verfügbarkeit atomaren Fluors. Dieses wird bei der Zerlegung von NF3 frei gesetzt und steht der Reaktion zur Verfügung. Die NF3-Zerlegung in Fluor und Stickstoff wurde mit Hilfe der Massenspektrometrie (QMS) untersucht, Zerlegungsgrade größer 96% wurden erreicht. Mit Hilfe dieser Messung kann der Einfluss der Kammerreinigung auf den Treibhausgasausstoß (GWP) bestimmt werden. Mit dem Ar/NF3-Verfahren können die GWP-Emissionen um 90% im Vergleich zur RIE-Ätzung mit SF6 reduziert werden. Mit Argon/Chlor-Plasmen konnte kein Titannitrid geätzt werden, da die physikalische Sputterkomponente fehlte. Durch Hinzufügen von Chlor zu einer Ar/NF3-Gasmischung konnte die Ätzrate um bis zu 270% im Bereich niedrige Temperaturen/niedriger Druck gesteigert werden. Bei höheren Temperaturen/höherem Druck fielen die Ar/NF3/Chlor Ätzraten allerdings deutlich hinter die des Ar/NF3 zurück. Die dazu führenden Effekte werden untersucht und ausgeführt. Die Nutzung von externen Plasmaquellen bietet eine vielversprechende Alternative um Abscheideanlagen von TiN-Rückständen reinigen zu können. Bei hohen Temperaturen werden deutlich höhere Ätzraten als bei anderen Schichten (SiN, SiO2, W) erreicht. Für Anwendungen im niedrigen Temperaturbereich erlaubt die Zugabe von Chlor interessante Anwendungsmöglichkeiten. / Demands on state of the art deposition technologies for semiconductor production focus on uniformity, repeatability and low defectivity. The chamber condition is a key parameter to achieve these high demands in chemical vapour deposition (CVD) processes and are even more critical to the atomic layer deposition processes (ALD). During the deposition process not only the wafer surface but other chamber parts as well are covered with a thin film. This film accumulates during the deposition cycles and is prone to fall off the walls and pollute the wafer surface. The chamber parts that are exposed to the deposition must be set back to a steady state so that no deposits fall off the walls. The chamber condition also changes uncontrolled with varying film condition on the wall. A new approach for cleaning of ALD-titanium nitride (TiN) deposition chambers was investigated. To determine etch rates TiN-samples (created by ALD, CVD and PVD) were placed on a temperature controlled sample holder. An argon/NF3 mixture was excited in an upstream remote plasma source (RPS) and then routed through the reaction chamber. No further plasma activation inside the reaction chamber was done. The etching was monitored by in-situ reflectometry and etch rates were calculated. The effect of chlorine addition was also studied and strong influence on etch rates was found. The etch rate of TiN is dependent exponentially on temperature and very low etch rates were achieved below 70◦C at a chamber pressure ranging from 20-300 Pa. It was found that this correlates very well with the vapour pressure of the reaction product TiF4. At temperatures of 300◦C etch rates up to 800 nm/min were achieved. The optimum pressure for etching was found at 100 Pa while the pressure effect was small. The etch rate was mainly dependent on the availability of activated fluorine to create TiF4 by the reaction 2 NF3 → N2 + 6 F* 2 TiN + 8 F* → 2 TiF4 + N2 The NF3 decomposition to nitrogen and fluorine was monitored by quadrupole mass spectrometry (QMS) and was found to be greater than 96%. This figure allows an estimation of the amount of Global warm potential (GWP) gas emmited by the process for environmental considerations. Using argon/NF3 or argon/fluorine mixtures in RPS devices reduces the GWP emissions by more than 90% compared to RIE plasma cleaning with SF6. No etching occurred by using argon/chlorine only mixtures as no physical etch component was involved in RPS etch. However adding chlorine to the argon/NF3 mixture accelerated the etching process. Chlorine addition to the argon/NF3 mixture increased the etch rates up to 270% in the low pressure/low temperature regime. At higher temperatures or higher pressures the etch rates dropped below the etch rates achieved solely with fluorine chemistry. It must be emphasized that there is no physical acceleration of the ionized molecules toward the etched sample in this remote plasma setup. The usage of a remote plasma offers an alternative way to remove residues from chambers running TiN deposition processes. At high temperatures the Ar/NF3 offers remarkably high etching rates for TiN compared to other films (silicon nitride, -oxide, tungsten) usually cleaned by remote plasma. For low temperature applications the chlorine enhancement offers an interesting alternative to accelerate the etch process.

Two technologies, namely Laser Technology and Surface Modification Technology, have made rapid strides in the last few decades. The lasers have evolved from a simple laboratory curiosity to a matured industrial tool and its applications are limited only by imagination. Intense, coherent and monochromatic laser sources with power outputs ranging over several orders of magnitude have found innumerable applications in the realm of materials engineering. Reactive Pulsed Laser Deposition (PLD) is a powerful technique that utilises the power of a nanosecond pulsed laser for materials synthesis. Unlike conventional PLD, which require high density targets that are difficult to synthesize at a reasonable cost, the RPLD circumvents the need for one such ceramic target. This thesis presents a detailed and judicious use of this technique for synthesis of hard ceramic multilayer coatings using elemental metal targets. Transition metal nitrides having rock salt structure are known to exhibit superior properties such as hardness and wear resistance and hence formed the basis for the development of first generation coatings. Further improvements through alloying of these binary compounds with metal or metalloid components lead to the development of second generation coatings. As the demand for functional materials increased, surface modification technology alias surface engineering, grew in leaps and bounds. As the large number of coating requirements for optimal performance could not be fulfilled by a single homogeneous material, third generation coatings, comprising multilayer coatings, were developed. It is this aspect of combining the advantages of RPLD process to synthesize ceramic multilayer coatings, provides the main motivation for the present research work. In this thesis, a systematic study presented for synthesis of nanocrystalline and stoichiometric TiN and NbN thin films using RPLD through ablation of high purity titanium and niobium targets, in the presence of low pressure nitrogen gas. A novel Secondary Ion Mass Spectrometry (SIMS) based analysis was developed to effectively deduce the important process parameters in minimum trials to arrive at desired composition. The validity of this SIMS based method, for optimization of process parameters to get stoichiometric nitride films, was proved beyond any speculation by corroborative Proton Elastic Backscattering Spectrometric (PEBS) analysis. SIMS was also used to characterize the [NbN/TiN] multilayers. The feasibility of growing nanocrystalline multilayers with varying thicknesses has been demonstrated. Nanomechanical properties including hardness and adhesion strength of monolithic TiN and NbN films and multilayers were evaluated. The thesis is organised into six chapters. The first chapter gives a brief account on the history and development of ‘surface engineering’. The second chapter provides a comprehensive description of the experimental facility developed in-house to pursue research on PLD grown ceramic thin films and multilayers. Thin film synthesis procedure for ex-situ SIMS and TEM analyses is described. Brief introduction is also presented on the characterization techniques used in this study to investigate the surface, interface and microstructural aspects of PLD grown films with underlying basic principles. The third and fourth chapter describes the synthesis and characterization of titanium nitride and niobium nitride thin films using RPLD technique, respectively. SIMS was used in depth profiling mode, for optimization of three important process parameters, viz., nitrogen gas pressure, substrate temperature and laser pulse energy, to get stoichiometric nitride films. Further, films were characterized using GIXRD, TEM, XPS and PEBS for their structure and composition. AFM measurements were made to elucidate the surface morphological features. PEBS was effectively used to estimate the nitrogen concentration in a quantitative manner and the results corroborate well with the SIMS measurements. Having succeeded in synthesizing stoichiometric TiN and NbN films, further studies on the nanomechanical properties of monolithic TiN and NbN films and their multilayers were carried out and these results form the contents of the fifth chapter. The findings of the work reported in this thesis are concluded in Chapter 6 and few possible suggestions were presented as future directions. Both the monolithic TiN and NbN coatings showed a deposition pressure dependent hardness variation. The hardness of these monolithic films was found to be around 30 GPa, higher than the hardness values obtained by other conventional techniques. Keeping total thickness of the multilayers constant at 1 μm, [NbN/TiN] multilayers having bilayer periods ranging from 50 nm to 1000 nm, were synthesized. A systematic enhancement in hardness upto ~ 40 GPa was observed for [NbN/TiN]10 with the modulus of the multilayer remaining almost constant. The pileup observed around the indentation edge is indicative of toughening in multilayers. The tribological properties of multilayer films showed a better performance in terms of low coefficient of friction and regeneration of coating surfaces as revealed from the nanotribological studies. Overall, the multilayer coatings exhibited better performance in terms of hardness, toughness and adhesion with the substrate material.