Patent ID: 7524744

Claim:
A method of producing an SOI wafer, comprising: forming an oxygen ion-implanted layer by implanting oxygen ions into a silicon wafer from one main surface of the silicon wafer; subjecting the silicon wafer to oxide film-forming heat treatment to convert the oxygen ion-implanted layer into a buried oxide film; subjecting the silicon wafer to internal thermal oxidation treatment of the buried oxide film, thereby producing an SOI wafer having an SOI layer on the buried oxide film, the subjecting the silicon wafer to internal thermal oxidation treatment of the buried oxide film being performed such that the buried oxide film is formed with a thickness greater than a thickness of the buried oxide film of the SOI wafer ultimately produced; and subsequently subjecting the silicon wafer in which the thicker buried oxide film is formed to a heat treatment to reduce the thickness of the buried oxide film, so as to form the buried oxide film to have a film thickness of 100 nm or less; wherein after the heat treatment to reduce the thickness of the buried oxide film is performed, a sacrificial oxidation treatment is further performed in order to adjust the film thickness of the SOI layer.