Patent ID: 7655993

Claim:
A semiconductor device comprising: a semiconductor substrate; and a first MISFET and a second MISFET formed over the substrate, the first MISFET having a first gate insulating film and a first gate electrode formed over the first gate insulating film, the second MISFET having a second gate insulating film and a second gate electrode formed over the second gate insulating film, wherein a thickness of the second gate insulating film is greater than a thickness of the first gate insulating film, wherein the second gate insulating film includes a first insulating film formed over the semiconductor substrate and a second insulating film formed between the first insulating film and the second gate electrode, wherein the second insulating film includes hafnium and oxygen and has a dielectric constant larger than that of the first insulating film, wherein the first insulating film includes a silicon oxide film subjected to a nitriding treatment, wherein the first gate insulating film includes the second insulating film formed between the semiconductor substrate and the first gate electrode, and wherein each of the first gate electrode and the second gate electrode includes a refractory metal film.