| 摘要 |
PURPOSE: To obtain a method for fabricating a semiplanar heterojunction bipolar transistor without exposing the base layer during fabrication. CONSTITUTION: Collector plugs 18 are implanted selectively in order to connect a subcollector layer 12 with the surface of a heterojunction bipolar transistor 10. A base layer 22, an emitter layer 24 and an emitter cap layer 26 are then formed on a collector layer 16 and the collector plugs 18 by second epitaxial growth. According to the method, the base layer 22 is not exposed to subsequently detrimental fabrication steps. Subsequently, the base layer 22 is connected with the surface of the heterojunction bipolar transistor 10 by implanting a base plug region 28 selectively. Finally, a base contact 32 and an emitter contact 30 are formed selectively in the heterojunction region on the base plug region 28 and the emitter cap layer 26.
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