Patent ID: 7790573

Claim:
A process for producing an SOI substrate comprising the steps of: forming an oxide film on at least the front surface of a first silicon substrate; implanting hydrogen ions through the surface of the first silicon substrate and thereby forming an ion implantation area on the inside of the first silicon substrate; laminating a second silicon substrate onto the first silicon substrate via the oxide film and thereby forming a laminated body of the first silicon substrate and the second silicon substrate bonded with each other; and heating the laminated body at a predetermined temperature and thereby separating the first silicon substrate at the ion implantation area and thereby obtaining an SOI substrate in which a thin film SOI layer is formed on the second silicon substrate via the oxide film; wherein the first silicon substrate is formed by slicing an ingot grown by a CZ method in an inorganic atmosphere including hydrogen, the ingot is made of an area [P I ] which is the area where interstitial silicon type point defects that do not get into an agglomerate exist in a perfect area [P], which is the area where there are not any agglomerate of vacancy type point defects or any agglomerate of interstitial silicon type point defects.