Patent ID: 7217612

Claim:
A method for manufacturing a semiconductor device, comprising the steps of: forming a body region by implanting to diffuse an impurity in a predetermined region of a semiconductor layer; after field-oxidizing a surface region of said semiconductor layer by way of the LOCOS method to form an insulating film, forming a first gate insulating film by patterning said insulating film while a resist film formed on a predetermined region of said insulating film is employed as a mask; forming a second gate insulating film on said semiconductor layer other than said first gate insulating film, and then forming a gate electrode so that said gate electrode is bridged over said first gate insulating film and said second gate insulating film; and forming a source region and drain region by implanting an impurity of an opposite conductive type to said body region into both a source forming region formed within said body region and a drain forming region formed within said semiconductor layer while a resist film having an opening is employed as a mask, wherein said first gate insulating film is not formed at a position lower than at least a surface position of said semiconductor layer in the step of forming said first gate insulating film.