Patent ID: 6989316

Claim:
A method for manufacturing a semiconductor device comprising: forming an insulating film on a semiconductor substrate; forming openings in the insulating film to partly expose a surface of the semiconductor substrate; forming a semiconductor layer which fills the openings and extends upward above the insulating film, by using the exposed portion as a seed to epitaxially grow; removing portions of the semiconductor layer outside the openings; making a top surface of the semiconductor layer within the openings lower than an opening surface of each of the openings; flattening the top surface of the semiconductor layer by heating the semiconductor layer in a first inert gas atmosphere, the inert gas including hydrogen; and reducing an interface level density between the semiconductor layer and the insulating film by heating the semiconductor layer in a second inert gas atmosphere, the inert gas including hydrogen, the interface level density after the heating in the second inert gas atmosphere being smaller than the interface level density before the heating in the second inert gas atmosphere and after the heating in the first inert gas atmosphere.