Low Injection Base Current Model for SiGe HBT in E-B Depletion Region

Abstract

Low injection profile of base current is of great importance while considering power-efficient system design. The base current in SiGe HBT at low VBEis higher than Si-BJT base current. This shows the adverse side of using the otherwise superior heterojunction SiGe-HBT over Si-BJT. This paper presents a physical model of low-injection base current and discusses the way this model can be used to estimate defect density in SiGe device.