Patent ID: 7807534

Claim:
A method for manufacturing a semiconductor device including a semiconductor substrate, a hetero-semiconductor region that forms a hetero-junction to a first surface of the semiconductor substrate and is composed of a hetero-semiconductor material having a different band gap from that of a semiconductor material of the semiconductor substrate, a gate insulating film formed in contact with a hetero-junction between the semiconductor substrate and the hetero-semiconductor region, a gate electrode formed in contact with the gate insulating film, a source electrode formed in contact with the hetero-semiconductor region, and a drain electrode formed in contact with the semiconductor substrate, the method comprising: forming a first hetero-semiconductor layer on the first surface of the semiconductor substrate, the first hetero-semiconductor layer including the hetero-semiconductor material; forming an etching stopper layer at a predetermined position on a portion of a first surface of the first hetero-semiconductor layer opposite to the semiconductor substrate, the etching stopper layer including a material having a different etching rate from that of the first hetero-semiconductor material; forming a second hetero-semiconductor layer on the exposed first surface of the first hetero-semiconductor layer and the etching stopper layer, the second hetero-semiconductor layer including a hetero-semiconductor material; removing the etching stopper layer; and thermally oxidizing the first hetero-semiconductor layer exposed by the removal of the etching stopper layer.