Refractory metal silicide cap for protecting multi-layer polycide structure.

摘要

A process for forming a capping layer over a titanium silicide layer includes forming a layer of polysilicon (16) over a gate-oxide layer (14). A layer of titanium (18) is then formed over the poly layer (16) followed by deposition of a composite layer of tantalum silicide (20). The structure is then patterned and subjected to an annealing process to form a titanium silicide layer (22) covered by the capping layer (20) of tantalum silicide. The tantalum silicide provides a much higher oxidation resistant layer with the underlying titanium silicide providing the desirable conductive properties needed for long runs of interconnects on a semiconductor structure.