Patent ID: 7220654

Claim:
A method for manufacturing a semiconductor substrate, comprising: forming an epitaxial layer on a semiconductor substrate by epitaxial growth; and forming an insulating layer by deposition at an interface between the epitaxial layer and the semiconductor substrate by performing a heat treatment that is performed in an oxidizing atmosphere, the insulating layer is formed in a such manner that the insulating layer has a thickness of about one hundred nanometers and a stratiform region of the insulating layer at the interface between the epitaxial layer and the semiconductor substrate is provided, wherein: the heat treatment for forming the insulating layer is performed at a temperature higher than about 1100° C.; the insulating layer is formed from a distortion layer as nuclei disposed at the interface between the epitaxial layer and the semiconductor substrate; and the distortion layer is formed by a difference of impurity concentration or a lattice constant between the epitaxial layer and the semiconductor substrate.