Failure mechanism and SPICE modeling of AlGaAs/GaAs HBT long-term current instability

The long-term current instability of AlGaAs/GaAs heterojunction bipolar transistor (HBT) is studied, and the physical mechanism contributing to such a behavior is investigated. Based on this, a model capable of predicting the HBT long-term current drift and mean time to failure (MTTF) is developed. In addition, such a model is implemented into SPICE circuit simulator, thus allowing the simulation of HBT circuits subjected to an electrical and thermal stress condition.