US Patent 7595538 Semiconductor device

A P-type MOSFET 120 includes a semiconductor substrate (N-well 102b); a gate insulating film formed on the semiconductor substrate, composed of a high-dielectric-constant film 108 which contains a silicate compound containing a first element selected from the group consisting of Hf, Zr and any of lanthanoids, together with N; a gate electrode formed on the gate insulating film, and is configured by a polysilicon film 114 containing a P-type impurity; and a blocking oxide film 110 formed between the gate insulating film and the gate electrode, blocking a reaction between the first element and the polysilicon film 114, and having a relative dielectric constant of 8 or above.