Patent ID: 8133788

Claim:
A method of manufacturing a semiconductor device, comprising: providing a device intermediate comprising a semiconductor substrate of a first general conductivity type, a semiconductor layer of the first general conductivity type disposed on a surface of the semiconductor substrate and a first insulating film disposed on the semiconductor layer; forming on the first insulating film a gate electrode having an opening therein; implanting a first impurity for the first general conductivity type into part of the semiconductor layer through the opening of the gate electrode; implanting a second impurity for a second general conductivity type into part of the semiconductor layer that is outside the gate electrode using the gate electrode as a mask; heating the device intermediate so that the first and second impurities are diffused so as to form an impurity region and a channel region that have an junction interface perpendicular to the surface of the semiconductor substrate; wherein during the heating of the device intermediate the impurity region of the first impurity and the channel region of the second impurity are formed simultaneously; forming a source region of the first general conductivity type in the channel region; and forming a second insulating film covering the gate electrode.