| 摘要 |
PROBLEM TO BE SOLVED: To provide a device structure which maintains highly reliable operation and has high frequency characteristics in a heterojunction bipolar transistor, and its manufacturing method. SOLUTION: In the heterojunction bipolar transistor, an n-type collector layer 12 formed of a III-V compound semiconductor, a p-type base layer 13, and an n-type emitter layer 14 whose forbidden band width is larger than that of a base layer form a lamination structure on a semiconductor board 10 in due order. In a structure in which a part of an n-type collector layer is exposed as an outside collector region, a part of a p-type base layer is exposed as an outside base region and an emitter electrode 18, a base electrode 17 and a collector electrode 16 are formed respectively, a part of an emitter layer covers an entire of an outside base region, a high concentration p-type semiconductor layer 19, which is doped with p-type impurities at least 1×10<18> m<-3> or more, is laminated on an emitter layer which is in an outside base region through selective growth, and a base electrode is formed on the high concentration p-type semiconductor layer.
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