Patent ID: 8653627

Claim:
A bipolar semiconductor device comprising: a collector region comprising a low-resistance layer of a first conductive type formed on one surface of a semiconductor crystal; a high-resistance layer of the first conductive type disposed on the collector region; a base region of a second conductive type disposed on the high-resistance layer of the first conductive type; low-resistance emitter regions of the first conductive type formed on an opposite surface of the semiconductor crystal; and a low-resistance base contact region of the second conductive type joined to the base region and disposed on both sides of the high-resistance layer of the first conductive type at the periphery of the emitter regions; and further having: a recombination-inhibiting semiconductor layer of the first conductive type or of the second conductive type formed on the surface of the semiconductor crystal between the base contact region and the emitter regions; wherein the recombination-inhibiting semiconductor layer is not joined to the base region, and the recombination-inhibiting semiconductor layer has an impurity concentration lower than an impurity concentration of the base region.