Semiconductor device and method of manufacturing the same including thicker insulating layer on lower part of electrode

摘要

A gate insulating film is provided on a channel region. A gate electrode includes a lower part and an upper part. The lower part has a lower surface and sides, and the upper part has a lower surface. The lower surface of the lower part contacts the gate insulating film. The upper part is longer than the lower part in a lengthwise direction of a gate electrode. The first insulating film is interposed between the lower surface of the upper part of the gate electrode and a semiconductor substrate. The first insulating film surrounds at least the sides of the lower part of the gate electrode, which face drain and source regions, and having parts interposed between the lower surface of the upper part of the gate electrode and the semiconductor substrate and made thicker than the other parts.