Self-aligned cobalt silicide layers of different thicknesses, e.g. for MOS transistors, are formed by locally thinning a titanium cover layer prior to reacting an underlying cobalt layer with silicon surfaces

摘要

Formation of self-aligned cobalt silicide layers of different thicknesses involves locally thinning a titanium cover layer (120) prior to reacting an underlying cobalt layer (118) with silicon surfaces. Self-aligned cobalt silicide layers of different thicknesses are formed during semiconductor device production by: (a) applying a cobalt layer (118) and then a titanium cover layer (120) onto the bare surfaces of a silicon substrate (102) and of a silicon layer structure on the substrate; (b) selectively reducing the titanium cover layer thickness above the layer structure surface; (c) reacting the cobalt layer (118) with the silicon substrate and silicon layer structure surfaces to form self-aligned cobalt silicide layers, a thicker cobalt silicide layer being formed on the bare silicon layer structure surface; and (d) removing the titanium cover layer (120) and the unreacted cobalt.