Patent ID: 7199024

Claim:
A method of manufacturing a semiconductor device, said method comprising the steps of: forming a silicon oxide film on a first single crystal silicon substrate; adding hydrogen to the first single crystal silicon substrate through the silicon oxide film to form a hydrogen added layer in the first single crystal silicon substrate bonding the first single crystal silicon substrate to a second substrate through the silicon oxide film with a bonded interface therebetween, said second substrate being as a support; separating the first single crystal silicon substrate by a first heat treatment; carrying out a second heat treatment to a single crystal silicon film which remains on the second substrate in the separating step so that the bonded interface becomes stable wherein trap levels and defects are generated due to the second heat treatment; flattening a surface of the single crystal silicon film; forming a silicon island by patterning the single crystal silicon film after carrying out the second heat treatment; and thermally oxidizing the silicon island to reduce the trap levels and defects from the silicon island.