Initial Growth Process of TiN Films in Ultrahigh-Vacuum Rapid Thermal Chemical Vapor Deposition

Abstract

We have investigated an initial stage of titanium nitride (TiN) growth on SiO2 substrates by ultrahigh-vacuum chemical vapor deposition with TiCl4 and NH3 as source materials. The behaviors of nucleation and grain growth of TiN have been clarified by atomic force microscopy and transmission electron microscopy. It was found that TiN film formation at an initial stage consists of three stages, which are characteristic of the lateral and subsequent vertical growth processes of grains. Deposition time dependence of the lateral growth of TiN grains clearly indicates that a process at 550°C is limited by the surface reaction, irrespective of the TiCl4 flow rate and a pretreatment for the substrates before the deposition. The pretreatment affects in the generation of additional nucleation sites on the SiO2 surface but does not affect the mechanisms of nucleation and grain growth.