Microstructure, Mechanical and Tribological Properties of Ternary Transition Metal Nitride Coatings

The evolution of transition metal nitride (TMN) coatings with excellent mechanical and tribological properties has been shown to be a successful strategy in protecting tool components. In this thesis, the microstructure, mechanical properties and tribological performances of a range of TMN-based coatings, synthesised by physical vapor deposition techniques, were explored. First, the influence of substrate bias, on the structure and properties of magnetron sputtered TiSiN coatings was investigated. Enhanced scratch resistance i.e., higher critical loads (Lc1 and Lc2) was found in the coating deposited at the lower bias voltage (-40 V), which was ascribed to higher H/Er and H3/Er 2 ratios arising from fine nanocomposite structure and the presence of a higher compressive residual stress. An approximately 21% increase in wear rate was obtained for the coating prepared at higher bias (-50 V), which was attributed to slightly higher Si concentrations (~9.4 at.%) and, in turn, lower hardness. Further, a notable increase in Lc1 (~54%) and Lc2 (~27%) values, was obtained for a thick TiSiN coating (magnetron sputtered at a different condition) in comparison to the binary TiN coating that were underlain by its superior mechanical properties and graded structure, promoting the capacity to resist crack formation and delamination. Furthermore, the influence of Ni content, regulated by cathode composition, on the structure and properties of cathodic arc evaporated TiNiN coatings was examined. A transition from a fine columnar structure, at low Ni contents (~2 at.%), to a much finer equiaxed structure at higher Ni concentrations (≥ 4 at.%) was noted. In addition, the density of macroparticles generated during arcing was shown to be inversely related to the melting temperature of the target material. Finally, the effect of Ni content, controlled by the NiCr target current (INiCr) on the structure mechanical properties and scratch and wear behaviour of magnetron sputtered CrNiN coatings was studied. Significant damage-tolerance, coupled with good hardness values (greater than ~12 GPa), was found in the CrNiN coatings deposited at INiCr ≥2 A. The presence of a metallic nickel-rich phase, together with nanoscale porosity, may contribute to stress dissipation and help maintain structural integrity

Ti-Al-N-Based Hard Coatings: Thermodynamical Background, CVD Deposition, and Properties. A Review

For several decades, the increasing productivity in many industrial domains has led to a significant and ever-increased interest to protective and hard coatings. In this context, titanium-aluminum nitrides were developed and are now widely used in a large range of applications, due to their high hardness, good thermal stability, and oxidation resistance. This chapter reviews the thermodynamical characteristics of the Ti-Al-N system by reporting the progress made in the description of the Ti-Al-N phase diagram and the main mechanical and chemical properties of Ti1−xAlxN-based coatings. As a metastable phase, the existence of the fcc-Ti1−xAlxN depends on particular process parameters, allowing stabilizing this desirable solid solution. The influence of process parameters, with a particular interest for chemical vapor deposition (CVD) methods, on morphology and crystallographic structure is then described. The structure of Ti1−xAlxN thin films depends also on the aluminum content as well as on the annealing temperature, due to the spinodal nature of the Ti-Al-N system. These changes of crystallographic structure can induce an improvement of the hardness, oxidation resistance, and wear behavior of these coatings. The main mechanical and chemical properties of physical vapor deposition (PVD) and CVD Ti1−xAlxN-based coatings are also described

Magnetron Sputtering of Transition Metal Nitride Thin Films for Environmental Remediation

The current economic and ecological situation encourages the use of steel to push the technological limits and offer more cost-effective products. The enhancement of steel properties like wear, corrosion, and oxidation resistance is achieved by the addition of small amounts of chemical elements such as Cr, Ni, Si, N, etc. The steel surface can be protected by different treatments such as heating and coating, among others. For many decades, coatings have been an effective solution to protect materials using thin hard films. Several technologies for thin film deposition have been developed. However, some of them are restricted to certain fields because of their complex operating conditions. In addition, some deposition techniques cannot be applied to a large substrate surface type. The magnetron sputtering deposition process is a good option to overcome these challenges and can be used with different substrates of varying sizes with specific growth modes and for a wide range of applications. In this review article, we present the sputtering mechanism and film growth modes and focus on the mechanical and tribological behavior of nitride thin films deposited by the magnetron sputtering technique as a function of process conditions, particularly bias voltage and nitrogen percentage. The biomedical properties of transition metal nitride coatings are also presented

Cutting Edge Nanotechnology

The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters

Technologies of Coatings and Surface Hardening for Tool Industry

The innovative coating and surface hardening technologies developed in recent years allow us to obtain practically any physical–mechanical or crystal–chemical complex properties of the metalworking tool surface layer. Today, the scientific approach to improving the operational characteristics of the tool surface layers produced from traditional tools industrial materials is a highly costly and long-lasting process. Different technological techniques, such as coatings (physical and chemical methods), surface hardening and alloying (chemical-thermal treatment, implantation), a combination of the listed methods, and other solutions are used for this. This edition aims to provide a review of the current state of the research and developments in the field of coatings and surface hardening technologies for cutting and die tools that can ensure a substantial increase of the work resource and reliability of the tool, an increase in productivity of machining, accuracy, and quality of the machined products, reduction in the material capacity of the production, and other important manufacturing factors. In doing so, the main emphasis should be on the results of the engineering works that have had a prosperous approbation in a laboratory or real manufacturing conditions

Two-Dimensional Electronic Materials and Devices: Opportunities and Challenges

The unprecedented growth of the Internet of Things (IoT) and the 4th Industrial Revolution (Industry 4.0) not only demands dimensional scaling of device technologies but also new types of applications beyond today’s electronics. Two-dimensional (2D) materials, a group of layered crystals (such as graphene and MoS2) with unique properties, have emerged as promising candidates for IoT and Industry 4.0 since they can, not only extend the scaling with unprecedented performance and energy efficiency but also exhibit high potential for novel electronic devices. However, such nanomaterials suffer from significant challenges in process integration, especially in the modules that involves the formation of interfaces between 2D materials and conventional bulk materials. Thus, realizing high-performance energy-efficient 2D electronic devices has been challenging. This dissertation focuses on understanding the fundamental issues in such 2D materials (such as contacts, interfaces and doping) and in identifying applications uniquely enabled by these materials.First, a comprehensive treatment of metal contacts to 2D semiconductors, which has been a huge hurdle for 2D electronic technologies, will be presented. As a pioneering study, new interface physics originating from the unique dimensionality and surface properties have been revealed [1]. Solutions to minimize contact resistance are described though techniques of interface hybridization [2] and seamless contacts [3], [4]. These techniques transform 2D semiconductors from solely scientifically-interesting materials into high-performance field-effect transistor (FET) technologies, such as MoS2 FETs with record-low contact resistances [5], [6] and WSe2 FETs with record-high drive current and mobility [7]. Beyond metal interfaces, dielectric interface is crucial for preserving the carrier mobility in 2D channels, for which a solution enabled by buffer layers has been proposed [8]. On the other hand, the vertical van der Waals interfaces between 2D and 3D semiconductors, which retain the advantages of pristine ultra-thin 2D films as well as maximized tunneling area/field, have been studied and exploited into a novel beyond-silicon transistor technology – the first 2D channel tunnel FET (TFET) [9], which beat the fundamental limitation in the switching behavior of transistors. Recent results from the engineering of such 2D-3D semiconductor interfaces by surface reduction/passivation are described, showing a significant boost of drive current. While conventional diffusion/ion implantation methods are infeasible for 2D materials, two efficient doping techniques that are specific for 2D materials – surface doping [10], [11] and intercalation doping [12] are presented. The theoretical study of surface doping using ab-initio methods helped develop a novel doping scheme that uniquely exploits the Lewis-base like pedigree of 2D semiconductors without disturbing the structural integrity of the 2D atomic layer configuration [13], as well as a novel electrocatalyst based on MoS2 that achieved record high hydrogen evolution reaction (HER) performance [14]. On the other hand, intercalation doping has been employed to demonstrate graphene based transparent electrodes with the best combination of transmittance and sheet resistance [12], and also the first graphene interconnects with excellent performance, reliability and energy-efficiency [15], [16]. Moreover, by uniquely exploiting the high kinetic inductance and conductivity of intercalation doped graphene, a fundamentally different on-chip inductor has been demonstrated [17], [18], with both small form-factors and high inductance values, that were once thought unachievable in tandem. This 2D technique provides an attractive solution to the longstanding scaling problem of analog/radio-frequency electronics and opens up an unconventional pathway for the development of future ultra-compact wireless communication systems. Finally, a novel dissipative quantum transport methodology based on Büttiker probes with band-to-band tunneling capability is developed for 2D FETs [19]. Subsequently, gate-induced-drain-leakage (GIDL), one of the main leakage mechanisms in FETs especially access transistors, is evaluated for the first time for 2D FETs. The results establish the advantages of certain 2D semiconductors in greatly reducing GIDL and thereby support use of such materials in future memory technologies.The dissertation concludes with a vision for how a smart life can be realized in the future by harnessing the capabilities of various 2D technologies in the era of IoT and Industry 4.0.[1] J. Kang, D. Sarkar, W. Liu, D. Jena, and K. Banerjee, “A computational study of metal-contacts to beyond-graphene 2D semiconductor materials,” in IEEE International Electron Devices Meeting, 2012, pp. 407–410.[2] J. Kang, W. Liu, D. Sarkar, D. Jena, and K. Banerjee, “Computational Study of Metal Contacts to Monolayer Transition-Metal Dichalcogenide Semiconductors,” Phys. Rev. X, vol. 4, no. 3, p. 31005, Jul. 2014.[3] J. Kang, D. Sarkar, Y. Khatami, and K. Banerjee, “Proposal for all-graphene monolithic logic circuits,” Appl. Phys. Lett., vol. 103, no. 8, p. 83113, 2013.[4] A. Allain, J. Kang, K. Banerjee, and A. Kis, “Electrical contacts to two-dimensional semiconductors,” Nat. Mater., vol. 14, no. 12, pp. 1195–1205, 2015.[5] W. Liu et al., “High-performance few-layer-MoS2 field-effect-transistor with record low contact-resistance,” in IEEE International Electron Devices Meeting, 2013, pp. 499–502.[6] J. Kang, W. Liu, and K. Banerjee, “High-performance MoS2 transistors with low-resistance molybdenum contacts,” Appl. Phys. Lett., vol. 104, no. 9, p. 93106, Mar. 2014.[7] W. Liu, J. Kang, D. Sarkar, Y. Khatami, D. Jena, and K. Banerjee, “Role of metal contacts in designing high-performance monolayer n-type WSe2 field effect transistors.,” Nano Lett., vol. 13, no. 5, pp. 1983–90, May 2013.[8] J. Kang, W. Liu, and K. Banerjee, “Computational Study of Interfaces between 2D MoS2 and Surroundings,” in 45th IEEE Semiconductor Interface Specialists Conference, 2014.[9] D. Sarkar et al., “A subthermionic tunnel field-effect transistor with an atomically thin channel,” Nature, vol. 526, no. 7571, pp. 91–95, Sep. 2015.[10] Y. Khatami, W. Liu, J. Kang, and K. Banerjee, “Prospects of graphene electrodes in photovoltaics,” in Proceedings of SPIE, 2013, vol. 8824, p. 88240T–88240T–6.[11] D. Sarkar et al., “Functionalization of Transition Metal Dichalcogenides with Metallic Nanoparticles: Implications for Doping and Gas-Sensing,” Nano Lett., vol. 15, no. 5, pp. 2852–2862, May 2015.[12] W. Liu, J. Kang, and K. Banerjee, “Characterization of FeCl3 intercalation doped CVD few-layer graphene,” IEEE Electron Device Lett., vol. 37, no. 9, pp. 1246–1249, Sep. 2016.[13] S. Lei et al., “Surface functionalization of two-dimensional metal chalcogenides by Lewis acid–base chemistry,” Nat. Nanotechnol., vol. 11, no. 5, pp. 465–471, Feb. 2016.[14] J. Li, J. Kang, Q. Cai, W. Hong, C. Jian, and W. Liu, “Boosting Hydrogen Evolution Performance of MoS2 by Band Structure Engineering,” Adv. Mater. Interfaces, vol. 1700303, 2017.[15] J. Jiang et al., “Intercalation doped multilayer-graphene-nanoribbons for next-generation interconnects,” Nano Lett., vol. 17, no. 3, pp. 1482–1488, Mar. 2017.[16] J. Jiang, J. Kang, and K. Banerjee, “Characterization of Self - Heating and Current - Carrying Capacity of Intercalation Doped Graphene - Nanoribbon Interconnects,” in IEEE International Reliability Physics Symposium, 2017, p. 6B.1.1-6B.1.6.[17] X. Li et al., “Graphene inductors for high-frequency applications - design, fabrication, characterization, and study of skin effect,” in IEEE International Electron Devices Meeting, 2014, p. 5.4.1-5.4.4.[18] J. Kang et al., under review.[19] J. Kang et al., under review

Characterization of High Power Impulse Magnetron Sputtering Discharges

La tendance actuelle dans le domaine du dépôt physique en phase vapeur porte en partie sur le développement de processus permettant une ionisation élevée du matériau pulvérisé. Cette forte ionisation permet d'obtenir des conditions favorables à la fabrication de couches minces très denses. C'est le cas de la pulvérisation magnétron pulsée de grande puissance (HiPIMS), une technique de dépôt récemment introduite dans les milieux académiques et industriels. Ainsi, une forte dissipation de puissance au niveau de la cible durant chaque impulsion HiPIMS mène à la génération d'un plasma de haute densité et à une ionisation considérable du matériau pulvérisé. Pour cette raison principale, la concetration en ions métalliques d'un plasma HiPIMS peut être élevée, ce qui peut mener à une auto-pulvérisation de la cible. Malgré les importants progrès tant dans la compréhension que dans l'application de cette nouvelle technique de dépôt, une multitude de questions reliées à la dynamique complexe des décharges HiPIMS restent ouvertes. Ces questions concernent nottement les décharges opérées dans des mélanges gazeux réactifs employés dans la préparation de revêtements protecteurs et optiques. Ainsi, à titre d'exemple, il existe très peu d'information concernant la propagation entre la cible et le substrat d'un plasma riche en métal lors de chaque impulsion HiPIMS. Ceci est pourtant un critère important facilitant l'optimisation des conditions de dépôt. Ajoutons qu'il existe plusieurs types de sources de puissance offrant des formes d'impulsion en courant et en tension très différentes, mais qu'aucune analyse rigoureuse de leur décharge respective menant à l'identiffication des avantages et des inconvénients sur le processus de dépôt n'est disponible en ce moment. Le but de la présente thèse consiste ainsi à répondre aux problématiques et aux besoins déffinis plus-haut. En premier lieu nous menons une étude approfondie des processus en phase gazeuse durant des impulsions HiPIMS opérées avec une cible de Cr dans des milieux de Ar, de O2/Ar, de N2 et un mélange de N2 et Ar (N2/Ar) en utilisant primordialement l'émission optique émanant des différentes espèces excitées par le plasma. Nous nous concentrons ensuite sur l'évaluation critique des deux types de décharges pulsées à grande puissance générées par----------abstract Recent development in the field of physical vapor deposition has shown a great interest in processes that provide high level ionization of the sputtered material, enabling thus the fabrication of dense coatings exhibiting superior material and functional characteristics. This is particularly the case of high power pulsed magnetron sputtering (HiPIMS), recently introduced to both academia and industry, that combines magnetron sputtering and pulsed power technology. The high power dissipated on the target during each HiPIMS pulse leads to the generation of high-density plasma and to a significant ionization of the sputtered target material. Hence, the HiPIMS plasma can be rich in metal ions which, in turn, contribute to target self-sputtering. Despite great advances in the understanding as well as in the application of this novel deposition technique, there remain numerous open questions related to the complex dynamics of the pulsed HiPIMS discharges, particularly if operated in the reactive gas mixtures employed in the preparation of functional protective and optical lms. For instance, there is still little information available about the propagation of the metal-rich plasma in between the target and the substrate during individual HiPIMS pulses, an important criterion for facilitating the optimization of the deposition conditions. Furthermore, there exists a variety of commercial HiPIMS power supplies exhibiting very dierent pulse shape-, voltage- and current characteristics. However, a rigorous analysis of the respective discharges { that could identify their particular benets and drawbacks with respect to the deposition process { is missing. This work addresses the issues and needs dened above. First, we perform an in-depth investigation of the gas-phase processes during the HiPIMS pulses operated above a Cr target in Ar, O2, N2 and in N2/Ar mixtures, mostly using optical emission emanating from different plasma-excited species. Afterwards, we focus on the critical assessment of the two principal types of high power pulsed discharges generated by the commercially available power supplies

Circuits Techniques for Wireless Sensing Systems in High-Temperature Environments

RÉSUMÉ Dans ce projet, nous proposons de nouvelles techniques d’intégration basées sur la technologie de nitrure de gallium (GaN). Ces techniques permettent de mettre en œuvre un système de transmission de données sans fil entièrement intégré dédié aux capteurs de surveillance pour des applications d'environnement hostile. Le travail nécessite de trouver une technologie capable de résister à l'environnement sévère, principalement à haute température, et de permettre un niveau d'intégration élevé. Le système réalisé serait le premier dispositif de transmission de données basé sur la technologie GaN. En plus de supporter les conditions de haute température (HT) dépassant 600 oC, le système de transmission sans fil attendu devrait fonctionner à travers une barrière métallique séparant le module émetteur du récepteur. Une revue de la littérature sur les applications en environnements hostiles ainsi que sur l'électronique correspondante a été réalisée pour sélectionner la technologie AlGaN/GaN HEMT (transistor à haute mobilité d'électrons) comme une technologie appropriée. Le kit de conception GaN500, fourni par le Conseil national de recherches du Canada (CNRC), a été adopté pour concevoir et mettre en œuvre le système proposé. Cette technologie a été initialement introduite pour desservir les applications radiofréquences (RF) et micro-ondes. Par conséquent, elle n'avait pas été validée pour concevoir et fabriquer des circuits intégrés analogiques et numériques complexes et son utilisation à des températures extrêmes n’était pas validée. Nous avons donc caractérisé à haute température des dispositifs fabriqués en GaN500 et des éléments passifs intégrés correspondants ont été réalisés. Ces composants ont été testés sur la plage de température comprise entre 25 et 600 oC dans cette thèse. Les résultats de caractérisation ont été utilisés pour extraire les modèles HT des HEMT intégrés et des éléments passifs à utiliser dans les simulations. En outre, plusieurs composants intégrés basés sur la technologie GaN500, notamment des NOT, NOR, NAND, XOR, XNOR, registres, éléments de délais et oscillateurs ont été mis en œuvre et testés en HT. Des circuits analogiques à base de GaN500, comprenant un amplificateur de tension, un comparateur, un redresseur simple alternance, un redresseur double alternance, une pompe de charge et une référence de tension ont également été mis en œuvre et testés en HT. Le système de transmission de données mis en œuvre se compose d'un module de modulation situé dans la partie émettrice et d'un module de démodulation situé dans la partie réceptrice.----------ABSTRACT In this project, we propose new integrated-circuit design techniques based on the Gallium Nitride (GaN) technology to implement a fully-integrated data transmission system dedicated to wireless sensing in harsh environment applications. The goal in this thesis is to find a proper technology able to withstand harsh-environments (HEs), mainly characterized by high temperatures, and to allow a high-integration level. The reported design is the first data transmission system based on GaN technology. In addition to high temperature (HT) environment exceeding 600 oC, the expected wireless transmission systems may need to operate through metallic barriers separating the transmitting from the receiving modules. A wide literature review on the HE applications and corresponding electronics has been done to select the AlGaN/GaN HEMT (high-electron-mobility transistor) technology. The GaN500 design kit, provided by National Research Council of Canada (NRC), was adopted to design and implement the proposed system. This technology was initially provided to serve radio frequency (RF) and microwave circuits and applications. Consequently, it was not validated to implement complex integrated systems and to withstand extreme temperatures. Therefore, the high-temperature characterization of fabricated GaN500 devices and corresponding integrated passive elements was performed over the temperature range 25-600 oC in this thesis. The characterization results were used to extract HT models of the integrated HEMTs and passive elements to be used in simulations. Also, several GaN500-based digital circuits including NOT, NOR, NAND, XOR, XNOR, register, Delay and Ring oscillator were implemented and tested at HT. GaN500-based Analog circuits including front-end amplifier, comparator, half-bridge rectifier, full-bridge rectifier, charge pump and voltage reference were implemented and tested at HT as well. The implemented data transmission system consists of a modulation module located in the transmitting part and a demodulation block located in the receiving part. The proposed modulation system is based on the delta-sigma modulation technique and composed of a front-end amplifier, a comparator, a register, a charge pump and a ring oscillator. The output stage of the transmitter is intended to perform the load-shift-keying (LSK) modulation required to accomplish the data transmission through the dedicated inductive link. At the receiver level, three demodulation topologies were proposed to acquire the delivered LSK-modulated signals

Gas Discharge Plasmas and Their Applications (GDP 2019): 14th International Conference, September 15–21, 2019, Tomsk, Russia: abstracts

The book contains abstarcts of oral and poster reports presented at the 14th International Conference "Gas Discharge Plasmas and Their Applications" (GDP 2019). This event is a continuation of conferences on gas discharge physics held in Russia since 1984, as well as seminars and conferences on the technological application of low-temperature plasma. The conference is held every 2 years in different cities of the Russian Federation. This year, the wonderful Siberian city of Tomsk, known for its intellectual environment, was chosen as the venue. The program of the Conference covers a wide range of technical areas and modern aspects of the physical processes occurring in generators of lowtemperature plasma, low and high-pressure discharges, pulsed plasma sources, surface modification, and other gas-discharge technologies