Method of manufacturing an insulated gate type field effect semiconductor device

Claim 1

A method of manufacturing an insulated gate type field effect semiconductor device, which includes the steps of providing a silicon nitride film on the surface of a silicon substrate, selectively removing said silicon nitride film so as to define an exposed inactive area or areas and a non-exposed active area or areas in which at least the source, gate and drain of said semiconductor device are formed, forming an oxide film on the surface of said exposed inactive area or areas, and forming the gate comprising an oxide film in contact with the surface of said substrate and an overlying polycrystalline silicon or metal film and diffused source and drain, characterized by inclusion of the step of removing the surface portion of the substrate which includes defect in said active area or areas, after said step of removing said silicon nitride film is performed and before the step of forming the oxide film for said gate is carried out.

Claim 2

A method of manufacturing an insulated gate type field effect semiconductor device, which includes the steps of providing a silicon nitride film on the surface of a silicon substrate, selectively removing said silicon nitride film so as to define an exposed inactive area or areas and a non-exposed active area or areas in which at least the source, gate and drain of said semiconductor device are formed, forming an oxide film on the surface of said exposed inactive area or areas, and forming the gate comprising an oxide film in contact with the surface of said substrate and an overlying polycrystalline silicon or metal film and diffused source and drain, characterized by inclusion of the step of removing the surface portion of the substrate which includes defect in said active area or areas, after said step of removing said silicon nitride film is performed and before the step of forming the oxide film for said gate is carried out.