Patent ID: 8030198

Claim:
A method of manufacturing a semiconductor device including a gate electrode formed on a silicon substrate via a high-dielectric-constant material film having a higher dielectric constant than that of silicon oxide, and a source/drain region formed on a surface of the silicon substrate around the gate electrode, the method comprising: forming a silicon oxide film on the silicon substrate; nitrogenizing the silicon oxide film to form a silicon oxide-nitride film so that nitrogen having concentration equal to or higher than a predetermined concentration is introduced into the silicon oxide film within a range of a thickness from 0.2 nanometer to 1 nanometer from an interface with the silicon substrate, so that a peak of a depth-direction distribution of nitrogen concentration in the silicon oxide film is within 0.5 nanometer from the interface with the silicon substrate, and nitrogen concentration in the silicon oxide film is lowered from the interface with the silicon substrate toward the high-dielectric-constant material film, within the range of thickness; etching the silicon oxide-nitride film to a thickness to which the nitrogen in the predetermined concentration or more is introduced thereby forming an interface layer including a silicon oxide-nitride film introduced with nitrogen in the predetermined concentration or higher; and forming the high-dielectric-constant material film on the interface layer.