Reformation of an SiGe HBT structure for reducing the effect of parasitic barriers

In this paper, an n-p-n SiGe heterojunction bipolar transistor (HBT) is investigated. The emitter and collector of this transistor are made up of silicon, and germanium dopant is linearly diffused in the base region. Adding germanium dopant causes the formation of parasitic barriers in base-emitter junction of transistor. The barrier effects are reduced by this structure. In this model, choosing the proper dopant structure, the collector current density can be increased.