A phenomenological model for the reliability of GaAs based heterojunction bipolar transistors

Abstract

We present a phenomenological model for the lifetime prediction of GaAs based heterojunction bipolar transistors (HBTs). Both thermal activation process and recombination enhanced defect generation process were considered phenomenologically. At high stress temperatures, the lifetime of the transistor is determined by the thermal activation process and is independent of the stress current. But at low stress temperatures, the device’s lifetime is controlled by the recombination enhanced defect generation process and is dependent on the stress current. The model has been used to fit experimental data, and very reasonable agreement was obtained. The model is valid for all stress temperatures and stress currents. It provides a good guideline for projecting HBTs lifetimes using accelerated stress test.