a metal oxide semiconductor transistor is disclosed . the mos transistor includes : a semiconductor substrate ; a gate disposed on the semiconductor substrate , wherein the gate comprises two sidewalls ; a spacer formed on the sidewalls of the gate ; a source / drain region disposed in the semiconductor substrate ; a silicide layer disposed on top of the gate and the surface of the source / drain region ; and a retarded interface layer disposed in the junction between the silicide layer and the gate and source / drain region .