Morphology and preferred orientation of titanium nitride plates prepared by chemical vapour deposition

Abstract

Thick titanium nitride (TiNx; x = 0.74–1.0) plates (up to 2 mm thick) were prepared by chemical vapour deposition using TiCl4, NH3 and H2 as source gases at a total gas pressure, Ptot, of 4 kPa, deposition temperatures, Tdep, from 1373–1873 K, and NH3/TiCl4, mN/Ti, gas molar ratio from 0.17–1.74. The effects of deposition conditions on morphology, preferred orientation and composition of CVD-TiNx plates were investigated. Surface morphology changed from faceted to nodular texture with increasing mN/Ti and Tdep. The faceted and nodular deposits showed columnar and shell-like fracture cross-sections, respectively. The composition (x = N/Ti) increased with increasing mN/Ti and Tdep below mN/Ti = 1.0, and was constant above mN/Ti = 1.0. Three kinds of preferred orientations were observed: (100) orientation at low Tdep, (110) orientation at intermediate Tdep and low mN/Ti, and (111) orientation at high Tdep and high mN/Ti. This tendency is discussed thermodynamically, and explained as being due to changes in the degree of supersaturation in the gas phase.