Long-term current instability of AlGaAs/GaAs HBTs: an overview

This paper provides an overview of the long-term current instability of AlGaAs/GaAs heterojunction bipolar transistors (HBTs), which is a major concern in HBT reliability. Topics covered include: typical HBT post-burn-in characteristics; physical mechanisms contributing to the HBT long-term current gain drift; models for predicting the HBT mean time to failure (MTTF); and non-typical HBT post-burn-in behavior and its physical insight.