Process for forming refractory metal silicide layers of different

Abstract

A method for forming reactive metal silicide layers at two spaced locations on a silicon substrate, which layers can be of different thicknesses and/or of different reactive metals is provided. A sililcon substrate has a silicon dioxide layer formed thereon followed by the formation of a polysilicon layer on the silicon dioxide layer, followed by forming a layer of refractory metal, e.g. titanium on the polysilicon. A non-reflecting material, e.g. titanium nitride is formed on the refractory metal. Conventional photoresist techniques are used to pattern the titanium nitride, the titanium and polysilicon, and the titanium is reacted with the contacted polysilicon to form a titanium silicide. The portion of silicon dioxide overlying the silicon substrate is then removed and the exposed substrate is ion implanted to form source/drain regions. A second layer of refractory metal, either titanium or some other refractory metal, is deposited over the source/drain region, and either over the titanium nitride, or over the first formed silicide by first removing the titanium nitride. The second layer of refractory metal is reacted with the substrate at the source/drain region to form a refractory metal silicide, after which the unreacted refractory metal is removed.