摘要 |
A base layer made of SiGe mixed crystal includes a spacer layer formed in contact with a collector layer with no base impurities diffused therein and an intrinsic base layer formed in contact with an emitter layer with base impurities diffused therein. The spacer layer contains C at a low concentration. The intrinsic base layer has a first region containing C at a low concentration on the collector side and a second region containing C at a high concentration on the emitter side.
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