Patent ID: 9646873
Date: 2017-05-09
CPC Classifications: H01L

Claim:
1. A method for producing an SOS substrate comprising the steps of: implanting ions into a surface of a silicon substrate to forming an ion-implanted region, bonding the ion-implanted surface of the silicon substrate to a surface of a sapphire substrate via an insulating film, and separating the silicon substrate at the ion-implanted region, thus leaving an SOS substrate having a silicon layer on the sapphire substrate, wherein the face orientation of the sapphire substrate is a C-face having an off-angle of up to 1 degree, and wherein the sapphire substrate is heat treated at a temperature of 700 to 1,000° C. in a reducing atmosphere for reducing the concentration of metal impurities at the surface of the sapphire substrate and reducing the number of defects on the silicon layer of the SOS substrate prior to the step of bonding the sapphire substrate to the silicon substrate.