Experimental study of the instabilities observed in 650Â V enhancement mode GaN HEMT during short circuit

The paper presents the results of an experimental analysis of the short circuit behaviour of 650 V GaN power HEMT. It is shown that the DUTs exhibit two kinds of failure. A first failure mode involves large dissipated energies and can be attributed directly to the increase of the local temperature in the device. The second failure mode is less attributable to local thermal increase and it is proposed that it is associated with instabilities due to charge-field phenomena taking place in the device at high voltage. The paper shows that 650 V GaN power HEMTs are affected by high frequency oscillations which appear in the SC waveforms as it happens in the short circuit of the IGBTs.