Optimum Ge profile for the high cut-off frequency of SiGe HBT

Abstract

This paper analyzes the effects of Ge profiles shape of SiGe heterojunction bipolar transistors (HBT's). Device simulations using ATLAS/BLAZE for the SiGe HBT with trapezoidal or triangular Ge profile are carried out to optimize the device performance. A HBT with a 15% triangular Ge profile shows a higher cut-off frequency and DC current gain than that with a 19% trapezoidal Ge profile. The cut-off frequency and DC gain are increased from 42 GHz to 84 GHz and from 200 to 600, respectively.