Kinetics and microstructure of TiN coatings by CVD

Titanium nitride (TiN) coatings obtained by chemical vapor deposition with TiCl₄, H₂, and N₂ as gas sources at the atmospheric pressure have been examined in this study. The results showed that the deposition rate increased and reached a saturated value with increasing TiCl₄ partial pressure at different process parameters including deposition temperatures and partial pressures of H₂ and N₂. The reaction orders of TiCl₄, H₂, and N₂ were extracted by the least-square regression approximation of the experimental data. For TiCl₄ on N₂, their reaction order is influenced by the partial pressure of the other. A degraded growth rate at a high temperature of 1200°C was mainly related to the endothermic CVD TiN reaction and the hot-wall reactor. Microstructural examination by scanning electron microscope revealed the surface morphology changed with process parameters. Compositional analysis of the CVD TiN showed non-stoichiometric at low temperatures and 1200°C, but stoichiometric at 1000°C. The TiN stoichiometry could be affected by the partial pressures of N₂ and H₂.