The influence of emitter material on silicon nitride passivation-induced degradation in InP-based HBTs

The influence of emitter material on silicon-nitride (SiN) passivation-induced degradation in InP-based heterojunction bipolar transistors (HBTs) has been studied. It has been found that, compared to InP, InAlAs has a much higher resistance to NH₃-related plasma-induced damage. InP-based HBTs using InAlAs as the emitter can effectively suppress the degradation of device performance caused by dielectric passivation giving least deterioration on the device characteristics compared to the previously reported results concerning the passivation quality using different passivation schemes. Short-term high temperature and high current electrical stress tests indicates that the SiN-passivated devices using InAlAs as the emitter may have better stability than those with InP emitter. Our results suggest that engineering of emitter layer structures could be an alternative approach to suppress passivation-induced degradation in InP-based HBTs.