This book presents the status quo of the structure, preparation, properties and applications of tetrahedrally bonded amorphous carbon (ta-C) films and compares them with related film systems. Tetrahedrally bonded amorphous carbon films (ta-C) combine some of the outstanding properties of diamond with the versatility of amorphous materials. The book compares experimental results with the predictions of theoretical analyses, condensing them to practicable rules. It is strictly application oriented, emphasizing the exceptional potential of ta-C for tribological coatings of tools and components.

Amorphous carbon films with variable sp[sup 3] content were produced by ArF (193nm) pulsed laser deposition. An in-situ ion probe was used to measure kinetic energy of C[sup+] ions. In contrast to measurements made as a function of laser fluence, ion probe measurements of kinetic energy are a convenient as well as more accurate and fundamental method for monitoring deposition conditions, with the advantage of being readily transferable for inter-laboratory comparisons. Electron energy loss spectroscopy (EELS) and spectroscopic ellipsometry measurements reveal that tetrahedral amorphous carbon (ta-C) films with the most diamond-like properties are obtained at the C ion kinetic energy of[approximately]90 eV. Film properties are uniform within a 12-15[degree] angle from the plume centerline. Tapping-mode atomic force microscope measurements show that films deposited at near-optimum kinetic energy are extremely smooth, with rms roughness of only[approximately] 1[angstrom] over distances of several hundred nm. Field emission (FE) measurements show that ta-C does not appear to be a good electron emitter. After conditioning of ta-C films deposited on n-type Si a rather high turn-on voltage of[approximately]50 V/[micro]m was required to draw current of[approximately]1 nA to the probe. The emission was unstable and typically ceased after a few minutes of operation. The FE tests of ta-C and other materials strongly suggest that surface morphology plays a dominant role in the FE process, in agreement with conventional Fowler-Nordheim theory.

ABSTRACT: Diamond and diamond-like carbon films, with their exceptionally good mechanical, chemical, and optical properties, are the best materials as protective hard coatings for electronic devices and cutting tools. The biocompatibility of these materials makes it suitable for bone implants. The wide range applications of these films are hindered because of the high compressive stresses developed during the deposition. Use of carbide and nitride interfacial layers has emerged as one of the methods to reduce the compressive stresses. The present research focuses on the study of different materials as the interfacial layers for diamond and tetrahedral amorphous carbon films. For tetrahedral amorphous carbon AlN, Ta, TiN, TiC, TaN and W were investigated as the interlayer materials. The interlayer was deposited at different substrate temperatures to study the temperature induced changes in the residual stress. The tetrahedral amorphous carbon with TiN interlayer deposited at 300°C and 600°C exhibited a maximum reduction in the stress. TiN and TiC were deposited as interlayer for the diamond films on Ti-6Al-4V alloy. TiC has improved the adhesion of diamond with the substrate and exhibited less compressive stresses compared to TiN.

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Amorphous, hydrogenated carbon (AHC) films can be deposited on various substrates using several techniques, e.g. plasma deposition and ion beam deposition. The resulting films can be hard, wear resistant and transparent.