Patent ID: 8409959
Filing Date: 2013-04-02
Classification: H01L,H03K

Abstract:
1. A method for forming a bipolar transistor, comprising: forming a collector on a semiconductor substrate; vertically forming a single crystal silicon pillar above the collector; forming an emitter above the pillar; forming a base to connect the emitter and collector; and forming a number of base links in the single crystal silicon pillar each having an upper surface that contacts a bottom surface of an intrinsic base region and vertically links an extrinsic base region to the intrinsic base region to form a vertical base contact by actively driving dopants horizontally from the extrinsic base region into the single crystal silicon pillar, wherein the number of base links are at least partially in an area below the emitter and at least partially in an area between a first sidewall of the emitter and a second sidewall of the emitter.