Semiconductor device

Patent Granted A semiconductor device is provided with a semiconductor layer (SOI layer) arranged on an SOI substrate, and a gate electrode arranged on the SOI layer. The semiconductor device is also provided with at least a MOS transistor of one type which is normally off by setting the thickness of the SOI layer to have the thickness of a depletion layer due to work function difference between the gate electrode and the SOI layer larger than the thickness of the SOI layer.