Patent ID: 7084046

Claim:
A method of fabricating an SOI wafer comprising: a bonding step that comprises: providing a first substrate, providing a second substrate that comprises a silicon single crystal wafer, forming an insulating film on a first main surface of at least one of the first substrate and the second substrate, and bonding the first substrate to the second substrate with the insulating film between the first substrate and the second substrate; a first thinning step that comprises reducing a thickness of the second substrate to a first thickness to obtain an SOI layer bonded to the first substrate; a high-temperature annealing step that comprises annealing the SOI layer bonded to the first substrate at a temperature in a range of 1,000 to 1,3000° C.; an etch-stoppable, ion-implanted-layer forming step that is conducted after said high-temperature annealing step and that comprises: performing ion implantation from a surface of the SOI layer to form an etch-stoppable, ion-implanted layer by ion implantation having a concentration peak at a predetermined depth from the surface of the SOI layer; optionally forming an etch-stop layer from the etch-stoppable, ion-implanted layer; and a second thinning step that comprises selectively etching the SOI layer bonded to the first substrate to obtain an SOI wafer having an SOI layer with a second thickness; wherein the second thickness is smaller than the first thickness.