Patent ID: 7659169

Claim:
Method of manufacturing a semiconductor device with a dual gate field effect transistor, in which method a semiconductor body of a semiconductor material is provided at a surface thereof with a source region and a drain region of a first conductivity type and with a channel region of a second conductivity type opposite to the first conductivity type between the source region and the drain region and with a first gate region separated from the surface of the semiconductor body by a first gate dielectric above the channel region and with a second gate region situated opposite to the first gate region and formed within a recess in an opposite surface of the semiconductor body so as to be separated from the channel region by a second gate dielectric, wherein the recess is formed by means of a local change of the doping of the channel region and by performing an etching step starting from the opposite surface of the semiconductor body, characterized in that the local change of the doping of the channel region is provided close to the surface of the semiconductor body and in that the semiconductor body in the channel region is etched with an etching agent for the material of the semiconductor body and the local change of the doping of the channel region is used as an etch stop region.