Patent ID: 7687348

Claim:
A method of producing a semiconductor device, comprising the steps of: preparing a semiconductor substrate having an insulation layer and a semiconductor layer formed on the insulation layer; forming a second separation area having a depth reaching the insulation layer in the semiconductor layer to define and surround an element area; forming a first separation area having a depth not reaching the insulation layer in the semiconductor layer with a shallow trench isolation method; forming an intermediate high-concentration body area between the first separation area and the second separation area; introducing a first conductive impurity into at least a surface layer of the intermediate high-concentration body area to convert the intermediate high-concentration body area to a high concentration body area; forming a gate electrode in the element area at a side of the first separation area opposite to the high-concentration body area; introducing a second conductive impurity having polarity opposite to that of the first conductive impurity into a first area and a second area at both sides of the gate electrode to form a source area having a depth not reaching the insulation layer and a drain area having a depth reaching the insulation layer so that a channel area is formed below the gate electrode between the source area and the drain area; and forming a body contact on the high-concentration body area.