Patent ID: 8435892

Claim:
A method of manufacturing a semiconductor device, comprising: forming a first insulating film over a semiconductor film; forming a gate electrode over the first insulating film; forming a second insulating film over the first insulating film and the gate electrode; doping the semiconductor film with a first impurity element through the first insulating film; etching a part of the first insulating film so as to expose a part of the semiconductor film; doping the semiconductor film with a second impurity element, so as to dope a first portion of the semiconductor film and so as not to dope a second portion of the semiconductor film, wherein the first portion is adjacent to the second portion; forming an interlayer insulating film over the gate electrode; forming a contact hole reaching the second portion of the semiconductor film in the interlayer insulating film by etching a part of the interlayer insulating film; and doping the second portion of the semiconductor film with the second impurity element through the contact hole, so that a concentration of the second impurity element in the second portion approaches to a concentration of the second impurity element in the first portion, wherein a part of the second insulating film is etched together with the part of the first insulating film on etching the part of the first insulating film, so as to form a side wall in contact with the gate electrode.