Patent ID: 8871615

Claim:
A method of manufacturing a semiconductor device, the method comprising: forming a first SiGe layer having a first profile of a concentration of Ge on a semiconductor substrate; forming a second SiGe layer having a second profile of a concentration of Ge on the first SiGe layer, the second profile lower than a first peak of the first profile; forming a mask layer on the second SiGe layer; etching the first SiGe layer and the second SiGe layer by anisotropic etching using the mask layer as a mask to form trenches; selectively removing the first SiGe layer exposed into the trenches to form a cavity under the second SiGe layer; and oxidizing side and lower surfaces of the second SiGe layer exposed in the trenches and the cavity to increase the concentration of Ge in the second SiGe layer.