Base current instability of AlGaAs/GaAs HBTs operated at low voltages

This paper provides an analysis of the physical mechanisms underlying the long-term base current instability the AlGaAs/GaAs heterojunction bipolar transistor (HBT). Which a current instability gives rise to the HBT long-term current gain drift and thus is a major concern for the HBT liability. Two different types of base current instability commonly found in the AlGaAs/GaAs HBT are reviewed, and a detailed analysis for one of the base current stabilities taking place in the low-voltage region is presented and discussed.