Patent ID: 7229882

Claim:
A method of manufacturing a field effect type semiconductor device having a stacked gate insulation film and a gate electrode on a semiconductor layer, comprising: a step of forming said stacked gate insulation film including the steps of forming a thermal oxide film on the semiconductor layer by thermal oxidation, and forming a CVD oxide film on said thermal oxide film by a CVD method, said stacked gate insulation film having nitrogen segregated at an interface region between at least one of said thermal oxide film and said semiconductor layer, and said gate electrode and said CVD oxide film, wherein a concentration of nitrogen along an entire length of the stacked gate insulation film, excluding the vicinity of both interface regions, is higher than the average concentration of nitrogen in the semiconductor layer or the gate electrode, and a ratio of a thickness of said CVD oxide film to that of an entire stacked gate insulation film is at least 20%.