Selective low temperature chemical vapor deposition of titanium

Abstract

The present invention concerns a completely selective and efficient method for chemical vapor deposition of titanium disilicide onto silicon regions of a silicon substrate including silicon dioxide regions. According to the method of the present invention a silicon substrate is heated to a low temperature. Silicon nucleation is induced by the introduction of a silicon precursor, such as silane. Silicon nucleates primarily on the silicon regions, with minimal nucleation on silicon dioxide regions. The silicon nuclei are then converted to titanium disilicide by the low pressure introduction of titanium tetrachloride with or without continued supply of silane. Etching, preferably using chlorine gas, is used to remove the titanium disilicide formed from conversion. The etching leaves the silicon dioxide regions completely intact, while the silicon region is slightly textured. Steady state growth is then induced on the silicon region with complete selectivity by the introduction of silane and titanium tetrachloride under low pressure and temperature conditions. During the steady state growth minimal silicon is consumed from the underlying silicon region.