| 摘要 |
PROBLEM TO BE SOLVED: To provide a structure of HBT wherein the breakdown voltage of a collector layer can be raised without changing the thickness of the collector layer and the carrier density. SOLUTION: In the heterojunction bipolar transistor, a GaAS sub-collector layer 7, a GaAs collector layer 6, a GaAs base layer 5, and an AlGaAs or InGaP emitter layer 4 are stacked in this order on a semi-insulating substrate 8, and a collector electrode 13 is formed on the sub-collector layer. Further, a base electrode 12 is formed on the base layer, and an emitter electrode 11 is formed on the emitter layer. The whole or part of the collector layer 6 consists of a layer 10 formed of a material such as AlAs, AlGaAs, AlPSb or the like which has a wider band gap than that of GaAs, resulting in raising the withstand voltage of the collector layer. COPYRIGHT: (C)2005,JPO&NCIPI
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