Patent ID: 7768076

Claim:
A semiconductor device comprising: an n-channel MISFET comprising first diffusion layers formed in a first region of a surface portion of a semiconductor substrate so as to sandwich a first channel region therebetween, a first gate insulating film formed on the first channel region, and a first gate electrode including a first metal film formed on the first gate insulating film, a first metal carbide film formed above the first metal film, and a first n-type polysilicon film formed on the first metal carbide film; and a p-channel MISFET comprising second diffusion layers containing boron as a dopant and formed in a second region of the surface portion of the semiconductor substrate so as to sandwich a second channel region therebetween, a second gate insulating film formed on the second channel region, and a second gate electrode including a second metal film formed on the second gate insulating film, a second metal carbide film formed above the second metal film, and a second n-type polysilicon film which is formed on the second metal carbide film and has a boron concentration of not more than 5×10 19 cm −3 in a portion adjacent to an interface with the second metal carbide film; and the semiconductor device further comprising a third metal film between the second metal film and the second metal carbide film, wherein the first metal film and the third metal film contain the same metallic element.