A method of forming a semiconductor device includes forming a silicide contact region of a field effect transistor (FET); forming a shallow impurity region in a top surface of the silicide contact region; and forming a stressed liner over the FET such that the shallow impurity region is located at an interface between the silicide contact region and the stressed liner, wherein the shallow impurity region comprises one or more impurities, and is configured to hinder diffusion of silicon within the silicide contact region and prevent morphological degradation of the silicide contact region.