Patent ID: 7667295

Claim:
A semiconductor device including a bipolar transistor, comprising: a semiconductor layer; a first-conductive-type deep well formed on a surface of the semiconductor layer; a second-conductive-type first base region formed on the surface of the semiconductor layer and formed in the deep well; a first-conductive-type collector extraction region provided apart from the first base region on the surface of the semiconductor; a second-conductive-type second base region formed in the deep well and provided between the first base region and the collector extraction region on the surface of the semiconductor layer; and an element separation insulating layer formed between the collector extraction region and the first base region, and formed on the second base region, wherein the second base region is connected to the first base region, and having an impurity concentration lower than an impurity concentration in the first base region, and wherein the second base region is shallower than the first base region.