Patent attributes
A permeation preventing film of a silicon nitride film 16 is inserted between a silicon substrate 10 and a High-k gate insulation film 18 to thereby prevent the High-k gate insulation film 18 from being deprived of oxygen, while oxygen anneal is performed after a gate electrode layer 20 has been formed to thereby supplement oxygen. The silicon nitride film 16, which is the permeation preventing film, becomes a silicon oxide nitride film 17 without changing the film thickness, whereby characteristics deterioration of the High-k gate insulation film 18 due to the oxygen loss can be prevented without lowering the performance of the transistor. The semiconductor device having the gate insulation film formed of even a high dielectric constant material can be free from the shift of the threshold voltage.
