Patent ID: 7435655

Claim:
A method for manufacturing a semiconductor device comprising: forming a gate insulating film containing oxide of Ti, Zr, Hf or Ta on a silicon substrate; forming a gate electrode on the gate insulating film; forming first diffused layers on a surface of the silicon substrate which sandwich the gate electrode; forming first gate side walls on the gate insulating film which sandwich the gate electrode in a gate length direction; converting a part of the gate insulating film which is not covered with the gate electrode and the first gate side wall into a low resistance precursor layer by supplying nitrogen, boron or carbon; converting the low resistance precursor layer into a low resistance layer by forming a mixture of nitride, boride or carbide of Ti, Zr, Hf or Ta and oxide of Ti, Zr, Hf or Ta by heat treatment; forming second gate side walls which sandwich the gate electrode and the first gate side wall; and forming second diffused layers in the silicon substrate which sandwich the gate electrode, the first gate side wall and the second gate side wall.