Patent ID: 8124465

Claim:
A method for manufacturing a semiconductor device, comprising: depositing a mask material on a first semiconductor layer formed of silicon on a semiconductor substrate via a buried insulating film, and patterning the mask material and the first semiconductor layer, to form the first semiconductor layer having a convex shape; forming gate insulating films on a pair of facing sides of the first semiconductor layer; depositing a gate electrode material on the buried insulating film, the gate insulating films, and the mask material, and pattering the gate electrode material, to form a gate electrode on the pair of facing sides and the upper surface of the first semiconductor layer via the gate insulating films and the mask material; forming gate electrode sidewalls on the sides of the gate electrode, and removing the mask material formed on the first semiconductor layer and not coated by the gate electrode and the gate electrode sidewalls; forming a source region and a drain region by the ion implantation of a predetermined impurity into the first semiconductor layer using the gate electrode and the gate electrode sidewalls as masks; forming an insulating film on the buried insulating film, the first semiconductor layer, the gate electrode, and the gate electrode sidewalls; planarizing the insulating film, and selectively removing the gate electrode sidewalls by wet etching to expose a part of the first semiconductor layer; removing the masks, and etching off the exposed first semiconductor layer; forming a second semiconductor layer composed of silicon germanium or silicon carbide on the removed region; and forming a source extension region and a drain extension region by the ion implantation of a predetermined impurity into the second semiconductor layer using the gate electrode and the insulating film as the masks.