Analysis of temperature dependence of Si-Ge HBT

In this paper the dependence of characteristics of SiGe heterojunction bipolar transistors on Ge mole-fraction and also variation of gain with temperature are presented. The simulation is carried out using a two dimensional device simulator, BISOF, based on finite element method. It is observed that the current gain of graded HBT improves when the temperature falls from 300 K to 200 K which matches well with the available experimental results.