A method for fabricating a semiconductor device includes the steps of first forming a gate structure on a substrate, forming a first spacer adjacent to the gate structure, forming a second spacer adjacent to the first spacer, forming an epitaxial layer adjacent to the second spacer, forming a second cap layer on the epitaxial layer, and then forming a first cap layer on the second cap layer. Preferably, a top surface of the first cap layer includes a V-shape and the first cap layer and the second cap layer are made of different materials.