Semiconductor device and process for manufacturing same

摘要

A process for manufacturing a semiconductor device includes the following steps applied to a semiconductor substrate having, on its main surface, a plurality of separation oxide films, formed in stripes parallel to each other, and gate oxide films formed in the regions placed between separation oxide films, wherein pieces of a polysilicon layer are formed so as to extend from areas above gate oxide films to areas above portions of separation oxide films on both sides of the gate oxide films and wherein a first resist is formed so as to cover the top surfaces of polysilicon layer: the injection step of injecting an impurity into polysilicon layer above separation oxide films; and the thermal diffusion step of carrying out a heat processing so that the injected impurity diffuses to the regions above gate oxide films within polysilicon layer.