Processing, microstructure and properties of chemical vapour deposited TiN/AIN films

TiN/AlN films were deposited by means of thermal Chemical Vapour Deposition (CVD). Composition of the films was able to be estimated from the ratios of the growth rates of single nitride phases, under the mass transfer rate limiting deposition conditions. The as-deposited films at 973K consisted of TiN and A1N phases, corresponding to different grains, which had scales of several tens of nanometers. Their grain growth rate was much lower than that of the single TiN films. Ternary nitride phase was formed by the post-annealing at 1273K. The film had highest hardness at the atomic ration of about Ti/Al=2, and the hardness was not altered very much after the post-annealing. When the composite films were oxidized in air, aluminum oxide layer was formed preferentially on the film surface.