Semiconductor devices having si and sige epitaxial layers

Abstract

Semiconductor devices include a substrate having first and second active regions; a P-channel transistor associated with the first active region and including at least one of source and drain regions; an N-channel field-effect transistor associated with the second active region and including at least one of the source and drain regions; first and second contact pad layers each including silicon (Si) and SiGe epitaxial layers on the source and drain regions the SiGe epitaxial layers being sequentially stacked on the Si epitaxial layers; an interlayer insulating film; a first metal silicide film on the SiGe epitaxial layer of the P-channel transistor and a second metal silicide film on the Si epitaxial layer of the N-channel transistor; and contact plugs on the first and second metal silicide films.