A method for fabricating a semiconductor device includes forming a gate insulation layer over a substrate, forming a conductive compound containing layer over the gate insulation layer, etching the conductive compound containing layer and the gate insulation layer to form a gate structure, forming a metal layer over the resultant structure obtained after the etching, and letting the metal layer to react with silicon from the substrate to form source and drain regions comprising a metal silicide layer over the substrate exposed on both sides of the gate structure, wherein the conductive compound containing layer does not react with the metal layer.