Base charge dynamics of abrupt base-emitter junction HBTs and its representation in transistor models

Abstract

Base charge dynamics in abrupt heterojunction bipolar transistors (HBTs) are determined by the thermionic/field emission boundary condition. As a result, their small and large signal models differ from those of bipolar junction transistors (BJTs), which obey the Shockley boundary condition. We compare the base charge dynamics in the abrupt HBT to the BJT case and derive the small and large signal models of the abrupt HBT. © 2007 IEEE.