Title : Research on degradation and failure mechanisms of un-clamped-inductive-switching characteristics of p-GaN HEMT device
Abstract:
Single UIS and repetitive UIS experiment are performed in this article to expound physical failure mechanisms in P-GaN HEMT devices. Vpeak and Ipeak are used as the metrics to evaluate the degradation of electrical parameters. In the single UIS tests, different load inductors, off-gate voltage and ambient temperature are chosen as var-iables to observe the failure phenomena in the device under test(DUT), while in the repeated UIS tests, the threshold voltage, on-state resistance, blocking characteristics and gate leakage current degradation and recovery are concluded and analyzed that Vth presents a negative shift, Ron and BV are restored to their initial value, and gate leakage shows a significant reduction at first and then ,after a duration of lagging, gradually recovers to some extent, but is unable to achieve its initial value. Combining failure point analysis via decapping with TCAD simulation and validation, it is found that hole trapping/detrapping in the p-GaN region dominate Vth and Igss degradation, while electron traps in the buffer dominate Ron and BV degradation.
