Correlation between process parameters, microstructure and hardness of titanium nitride films by chemical vapor deposition

Titanium nitride (TiN) films were grown on graphite and cemented carbide substrates by conventional chemical vapor deposition. The growth characteristics, microstructure and hardness of TiN films were evaluated. It was found that the preferred orientations and morphology of the TiN films are related to the deposition temperature and gas concentration. Lower deposition temperature favors the formation of twinned crystals and results in (2 1 1) textured film whereas higher deposition temperature favors twin-free crystals and results in (1 0 0) textured film. The hardness of TiN films depends on the film morphology and microstructure. The films with lower porosity, smaller grain size, and composed of a mixture of different types of crystals possess higher hardness. The hardness is over 2000 Hv 0.1 for films with a mixture of very fine lenticular-like crystals and pyramid crystals.