Nitriding of bulk titanium and thin titanium films in a NH3 low pressure plasma

Abstract

Abstract Nitriding of bulk titanium and titanium thin films deposited on silicon was investigated under low pressure NH 3 plasma conditions. Kinetic studies of bulk titanium nitriding allowed the mechanisms of titanium nitride formation to be elucidated. The evolution of the thin surface oxide layer during the treatment was examined by means of photoelectrochemistry experiments. The mechanisms of transport of nitrogen (migration and/or diffusion) are studied for different plasma parameters and sample temperatures, using the general laws of protective layer growth. Nitriding study of thin films of titanium (1000 A) deposited on silicon substrates pointed out that two competitive processes can occur. At the Ti-plasma interface, titanium was nitrided; at the TiSi interface, titanium silicide was formed by a solid state reaction. The use of a barrier layer, SiO 2 (1 μm), enhanced nitriding of the titanium film by preventing Ti and Si interdiffusion.