Failure mechanisms of enhancement mode GaN power HEMTs operated in short circuit

Power Electronics Reliability: State of the Art and Outlook

“…Short-circuit failure mechanisms are studied in [46][47][48][49]. The drain-to-source voltage distinguishes two failure modes of GaN devices.…”

“…The short-circuit withstand time is in the range of few µs or more when the testing voltage is below 350 V. This reduces to a few hundreds of ns when the voltage is above 350 V. The first failure mode is due to the temperature increase of the entire device (i.e. more than 1,000 K), causing damage to the surface metal [48,49]. The second failure mode is related to local thermal destruction in a relatively small region of the device [46], [48,49].…”

“…more than 1,000 K), causing damage to the surface metal [48,49]. The second failure mode is related to local thermal destruction in a relatively small region of the device [46], [48,49]. Specifically, it is observed that the righthand side of the gate field plate is the most sensitive part of the testing samples [49].…”

“…The second failure mode is related to local thermal destruction in a relatively small region of the device [46], [48,49]. Specifically, it is observed that the righthand side of the gate field plate is the most sensitive part of the testing samples [49]. From an application perspective, it can be noted that destructive short-circuits could happen within sub-µs under moderate voltage stresses.…”

Degradation of 600V GaN HEMTs under Repetitive Short Circuit Conditions

“…Although GaN HEMTs exhibit good performance in standard operating conditions, their behaviour and reliability under extreme stress needs to be thoroughly analysed. Short-circuit (SC) behaviour of emode GaN HEMTs has been already adressed by researchers, mostly focused on destructive tests without analysis of impacts of repetitive non-destructive SC stress [1,2]. Degradation after repetitive SC test was addressed e.g.…”