Patent ID: 7923754
Filing Date: 2011-04-12
Classification: H01L

Abstract:
1. A bipolar transistor having a subcollector layer, a collector layer, a base layer and an emitter layer, characterized in that: said subcollector layer is formed with a projection and recesses; said collector layer provided above an upper part of said projection of said subcollector is constituted as an intrinsic collector layer of the bipolar transistor; said collector layer provided above an upper part of said recesses of said subcollector is constituted as an extrinsic collector layer of the bipolar transistor; an insulator layer is buried between the recesses of said subcollector layer and said extrinsic collector layer; a boundary interface between said projection of said subcollector layer and said intrinsic collector layer is sandwiched between said insulator layer; said base layer is comprising of an intrinsic base layer and an extrinsic base layer, and is formed of a single crystal layer; a base electrode is provided on said external base layer of said base layer; and said subcollector layer is provided with a collector electrode.