SEMICONDUCTOR DEVICE AND ITS FABRICATING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device and its fabricating method in which such problems as desorption of grain, generation of defect in a gate oxide film and intrusion of impurities into a semiconductor substrate are eliminated. SOLUTION: The method for fabricating a semiconductor device comprises a step for injecting impurities into a polysilicon layer 4 above an isolation oxide film 2 for the polysilicon layer 4 formed from above a gate oxide film 3 to extend above a part of the isolation oxide film 2 on the opposite sides, and a first resist 5 covering the upper side of the polysilicon layer 4 on a semiconductor substrate 1 having a major surface on which a plurality of isolation oxide films 2 are formed linearly in parallel with each other and the gate oxide film 3 is formed in a region sandwiched by the isolation oxide films 2; and a thermal diffusion step performing heat treatment such that the injected impurities are diffused to a region above the gate oxide film 3 in the polysilicon layer 4.