Patent ID: 8026554

Claim:
A semiconductor device, comprising: a silicon substrate; and a field effect transistor comprising a gate insulating film over the silicon substrate, a gate electrode on the gate insulating film, and source and drain regions, wherein said gate electrode comprises, at least in part in contact with said gate insulating film, a first silicide region having an NiSi2 phase and containing a p-type impurity element and a second silicide region having an NiSi phase disposed above the first silicide region; the silicide making up said crystallized Ni silicide region is of a composition represented by Ni x Si 1-x (0.2≦x<0.4); and said gate insulating film comprises a silicon oxide film, a silicon oxynitride film or a silicon nitride film, the silicon oxide film, the silicon oxynitride film or the silicon nitride film being in contact with said crystallized Ni silicide region of the gate electrode.