Patent ID: 7879657

Claim:
A method for manufacturing a semiconductor device wherein a MOSFET is formed in a monocrystal silicon layer of an SOS substrate in which the monocrystal silicon layer is laminated on a sapphire substrate, comprising: selectively forming an insulating film layer in a region for forming a channel of the MOSFET on the sapphire substrate; forming an epitaxial layer on the sapphire substrate in a region other than the insulating film layer, and forming a silicon layer on the insulating film layer; amorphizing the silicon layer and part of the epitaxial layer adjacent to the silicon layer by ion implantation to form an amorphous region within the epitaxial layer, the amorphous region having a top surface, a bottom surface opposite the top surface, and sidewalls extending between the bottom and top surfaces, the sidewalls adjoining with the epitaxial layer and the bottom surface is in direct contact with the sapphire substrate; and monocrystallizing the amorphous region by solid phase epitaxial growth from the epitaxial layer adjoining the sidewalls of the amorphous region, to form a silicon crystal layer under tensile stress from the epitaxial layer adjoining the sidewalls.