Patent ID: 7089525

Claim:
A semiconductor device comprising: a silicon-on-insulator substrate including a base substrate, an insulating layer over the base substrate, and a semiconductor layer over the insulating layer; an electric circuit formed over the silicon-on-insulator substrate; a plurality of semiconductor islands used as element-forming regions in a first area of the silicon-on-insulator substrate; and a plurality of first bipolar transistors formed in the respective semiconductor islands, and each respectively having an emitter region, a base region, and a collector region formed in the semiconductor layer; wherein the plurality of semiconductor islands are isolated from each other by grooves for isolating elements, the grooves reaching the semiconductor layer which become a buried oxide layer of the silicon-on-insulator substrate; and the emitter regions, the base regions, and the collector regions of the plurality of the first bipolar transistors are electrically parallel-connected by interconnection wirings respectively to act simultaneously and act as a large transistor.