Method for forming pFET device with silicon germanium channel

The invention provides a method for forming a pFET device with a silicon germanium channel, and the method comprises the steps: providing a semiconductor substrate, forming a pad oxide layer on the surface of the semiconductor substrate, and enabling the semiconductor substrate to comprise a sparse region and a dense region; forming a first groove in the semiconductor substrate and the pad oxide layer in the sparse region; forming a second groove in the semiconductor substrate and the pad oxide layer in the dense region, wherein the density of the first groove in the sparse region is smaller than that of the second groove in the dense region; performing epitaxial growth in the first groove and the second groove to form an epitaxial layer of which the surface is higher than the surface of the pad oxide layer; forming a sacrificial layer on the surfaces of the epitaxial layer and the pad oxide layer; and removing the sacrificial layer, the epitaxial layer and the pad oxide layer until all areas are completely e