Patent ID: 9590082
Date: 2017-03-07
CPC Classifications: H01L

Claim:
1. A device structure comprising: a first base layer on a first device region of a substrate; a first emitter on the first base layer, the first emitter defining a first junction with the first base layer; a second base layer on a second device region of the substrate; and a second emitter on the second base layer, the second emitter defining a second junction with the second base layer, wherein the first base layer and the second base layer differ in thickness, composition, concentration of an electrically-active dopant, or a combination thereof, wherein the second device region is defined by a plurality of trench isolation regions in the substrate, the first base layer is formed on the second device region and on the trench isolation regions, and a portion of the second base layer is positioned inside an opening extending through the first base layer to the second device region.