Patent ID: 9673294
Date: 2017-06-06
CPC Classifications: H01L

Claim:
1. A method of manufacturing a bipolar transistor structure, the method comprising: covering a collector region in a substrate with a first dielectric layer structure; forming a polysilicon layer over the first dielectric layer structure; forming a second dielectric layer structure over the polysilicon layer, the second dielectric layer structure covering the polysilicon layer; partially removing the second dielectric layer structure and the polysilicon layer to partially expose the first dielectric layer structure over the collector region and to expose a lateral side of the polysilicon layer; removing a portion of the polysilicon layer from the exposed lateral side of the polysilicon layer; removing the exposed first dielectric layer structure to at least partially expose the collector region; and growing epitaxial silicon over the collector region to form a base region, the epitaxially grown base region connecting to the polysilicon layer.