| 摘要 |
PROBLEM TO BE SOLVED: To reduce dispersion of the current gain (hfe) of a hetero-junction bipolar transistor. SOLUTION: The hetero-junction bipolar transistor has an emitter region and a collector region consisting of first conductive semiconductors, and a base region consisting of a second conductive semiconductor and has a region with a narrow band gap in the base region. A region whose thickness is larger than prescribed one, whose band gap is small and whose recombination current is large, for example, is given to the emitter region near the connection part of the base region and the emitter region. Since a neutral region with the narrow band gap is formed in the emitter region with such structure, recombination current increases and base current increases. Consequently, dispersion of base current by an interface oxide film, which is usually seen in a case when polycrystalline silicon is used in the emitter region, does not become conspicuous by base current increased by recombination, and dispersion of the current gain is reduced. COPYRIGHT: (C)2006,JPO&NCIPI
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