Deposition rates of titanium nitride plates prepared by chemical vapour deposition of TiCl4+NH3 system

Abstract

Titanium nitride plates (TiNx,x = 0.74−1.0, about 2 mm thick maximum) were prepared by chemical vapour deposition (CVD) using TiCI4, NH3 and H2 as source gases. The effects of CVD conditions, i.e. gas molar ratio (m N/Ti = NH3/TiCI4) and deposition temperature (Tdep), on deposition rates and surface morphology were examined, and the deposition mechanism of the CVD-TiNx plates was discussed. The relationship between mN/Ti and deposition rates showed a maximum peak at certainm N/Ti, and this maximum peak shifted to lowerm N/Ti with increasingT dep. The activation energy for the formation of CVD-TiNx plates was about 80 kJ mol−1 in the lower temperature range. The decomposition reaction of NH3 gas could be associated with the rate-controlling step. At higher temperatures, the diffusion process may be the rate-controlling step, and a large amount of powder (mainly NH4Cl) was formed in the gas phase. The highest deposition rate obtained in the present work was 1.06×10−7 ms−1 (0.38 mmh−1) atT dep = 1773 K andm N/Ti = 0.87.