SEMICONDUCTOR DEVICE AND MANUFACTURE THEREOF

PROBLEM TO BE SOLVED: To suppress deterioration of the electrical characteristics of a gate electrode and a gate insulating film to a minimum in a semiconductor device which is provided with the gate electrode consisting of a two-layer structure comprising a metal layer or an intermetallic compound layer. SOLUTION: When a gate electrode structure 10 is formed, first an intermetallic compound layer 6 is selectively removed until a polycrystalline silicon film 5 is exposed. After that, the film 5 at an exposed site is thermooxidized to remove the film 5, whereby the film 5 is made to remain under the lower layer of the compound layer 5 to form a polyside gate. Since etching of the layer 6 can be stopped at the time when the film 5 is exposed, damages to a gate oxide film 4 can be restrained to a minimum. Also because a charge which is stored in the patterned and isolated compound layer 6 can be allowed to escape via the film 5, it becomes possible to prevent the electrostatic breakdown of a gate electrode.