Temperature-dependent orientation of diamond films on titanium and structural evolution of interfacial layers

X-ray diffraction analytical techniques have been used to investigate the influence of the deposition temperature (650-850 degrees C) on the composition and microstructure of the transition layers formed at the interface between titanium substrates and diamond thin films. The diamond coatings were produced by hot-filament chemical vapor deposition using a 1% methane/hydrogen mixture. X-ray diffraction analysis, performed both through theta-2 theta scans and at grazing incidence, allowed investigation of the crystallographic properties and of the structural evolution of the various phases (TiC, TiH2, alpha-Ti) generated inside the intermediate reaction layers. The temperature-dependent orientation of diamond crystallites is discussed with reference to the complex structure of these interfacial layers. (C) 1996 American Institute of Physics.