Method of forming a complementary metal oxide semiconductor structure with n-type and p-type field effect transistors having symmetric source/drain junctions and optional dual silicides

Abstract

In a method of forming a semiconductor structure, different sections of a dielectric layer are etched at different stages during processing to form a first gate sidewall spacer for a first FET (e.g., a NFET) and a second gate sidewall spacer for a second FET (e.g., a PFET) such that the first and second gate sidewall spacers are symmetric. Raised source/drain regions for the first FET are formed immediately following first gate sidewall spacer formation and raised source/drain regions for the second FET are formed immediately following second gate sidewall spacer formation. Since the gate sidewall spacers of the two FETs are symmetric, the source/drain junctions of the two FETs will also be symmetric. Additionally, due to an etch stop layer formed on the raised source/drain regions of the first FET, but not the second FET, different metal silicides on the raised source/drain regions of the different FETs.