Patent ID: 8383489

Claim:
A method for forming an SOI wafer, comprising: preparing a monocrystalline silicon wafer on which a mask layer is formed; etching the mask layer and the monocrystalline silicon wafer to form several trenches; forming a first insulating layer on the sidewalls and the bottoms of the trenches; etching and removing the first insulating layer on the bottoms of the trenches; etching along the trenches the monocrystalline silicon wafer beneath the trenches to form cavities; processing the inner walls of the cavities to form a second insulating layer, the second insulating layers in adjacent cavities connecting with each other to split the monocrystalline silicon wafer into an upper sector of a top layer silicon and a lower sector of a silicon substrate; and filling up the trenches and the cavities with an insulating material layer.