Electrical degradation mechanisms of RF power GaAs PHEMTs

In this research, we have carried out a systematic investigation of the electrical degradation of RF power PHEMTs. By examining devices with different geometries as well as a variety of test structures, our research confirms previous observations of degradation under the gate of the device. We have also identified for the first time a mechanism that affects the source. Additionally, we convincingly show that impact ionization (II) is not directly responsible for drain degradation. Instead, we find that a hot-electron (HE)-induced chemical reaction at the surface of the drain, coupled with contact degradation appear to be the mechanisms responsible for the drain damage.