Semiconductor device formed in a semiconductor layer provided on an insulating film

摘要

A semiconductor device includes an insulating film provided on a semiconductor substrate and a semiconductor layer provided on the insulating film. An element separating insulating film separates element area. A first gate insulating film is provided on the semiconductor layer in the element area. A gate electrode is provided on the first gate insulating film. Source/drain diffusion layers are formed in the semiconductor layer sandwiching a channel area under the gate electrode therebetween. A potential applying section inducing a leak current which controls the potential of the semiconductor layer comprises a second gate insulating film provided on the semiconductor layer in the element area and a conductive film provided on the second gate insulating film and connected to the gate electrode. The potential applying section is configured so that a leak current through the second gate insulating film is larger than a leak current through the first gate insulating film.