Patent ID: 8026146
Filing Date: 2011-09-27
Classification: H01L

Abstract:
1. A method of manufacturing a bipolar transistor on a semiconductor substrate, the method comprising: providing on the semiconductor substrate a collector region of a first semiconductor material, which is of a first conductivity type and which adjoins an isolation region; forming a first base layer of a second semiconductor material, which is of a second conductivity type opposite to the first conductivity type, on the collector region and on the isolation region; forming a base window in the first base layer having a bottom surface, that exposes a top surface of the collector region and a portion of the isolation region, and having a sidewall that exposes a sidewall of the first base layer; forming a trench, which adjoins the collector region and a remaining portion of the isolation region, by removing the portion of the isolation region that is exposed by the base window; forming an isolation layer on the surface of the trench; forming a second base layer of a third semiconductor material of the second conductivity type on the sidewall of the first base layer, on the isolation layer and on the top surface of the collector region, thereby forming a field plate in the trench and a base region extending over the collector region, wherein the first base layer has an electrical connection to the field plate and the base region; and forming an emitter region of the first conductivity type in a top part of the base region in the base window.