Patent ID: 8278731

Claim:
A semiconductor device comprising: a SOI substrate including a support layer, a first insulation film and a SOI layer; a first circuit; a second circuit; and a trench separation element, wherein the SOI substrate further includes a first region and a second region, wherein the first region has the support layer, the first insulation film and the SOI layer, which are stacked in this order, and the second region has only the support layer, wherein the trench separation element penetrates through the support layer, the first insulation film and the SOI layer, wherein the trench separation element separates the first region and the second region, wherein the first circuit is disposed in the SOI layer of the first region, wherein the second circuit is disposed in the support layer of the second region, wherein the SOI substrate further includes a step between the first region and the second region, wherein a height of the step corresponds to a total thickness of the SOI layer and the first insulation film, wherein the first circuit includes a signal processing circuit, wherein the second circuit includes a plurality of electric elements, wherein the electric elements include a high power circuit, which handles electric power higher than electric power of the signal processing circuit, wherein the high power circuit includes an electrode, which is disposed on a backside of the second region, wherein the trench separation element includes a plurality of separation members, which is disposed in the second region, wherein each separation member penetrates the support layer, wherein the second region is divided into a plurality of second portions by the plurality of separation members, wherein each electric element is disposed in a corresponding second portion, and wherein the SOI substrate is a partial SOI substrate having the SOI layer partially.