Patent ID: 8501558

Claim:
A manufacturing method of a semiconductor device having a first MISFET of an n channel type and a second MISFET of a p channel type, comprising the steps of: (a) preparing a semiconductor substrate; (b) forming a first insulating film on said semiconductor substrate for forming a gate insulating film of each of said first and second MISFETs; (c) depositing metal elements on said first insulating film; (d) after said step (c), forming a silicon film on said first insulating film for forming a gate electrode of each of said first and second MISFETs; and (e) forming the gate electrode of each of said first and second MISFETs by patterning said silicon film, wherein, in said step (c), said metal elements are deposited on said first insulating film so that a surface density of said metal elements is within a range of 1×10 13 to 5×10 14 atoms/cm 2 , and wherein said first insulating film is composed of a silicon oxide film, and said method further comprises, after said step (c) and before said step (d), a step (c 1 ) of introducing nitrogen to said first insulating film to change said first insulating film into a silicon oxynitride film.