Observation of Dynamic V TH of p-GaN Gate HEMTs by Fast Sweeping Characterization

This is the authors' abstract. We don't add key points for this paper.

In this work, fast sweeping characterization with an extremely short relaxation time was used to probe the VTHinstability of p-GaN gate HEMTs. As the ID-VG sweeping time deceases from 5 ms to 5 μs, the VTHdramatically degenerates from 3.13 V to 1.76 V, meanwhile the hysteresis deteriorates from 22.6 mV to 1.37 V. Positive bias temperature instability (PBTI) measurement by fast sweeping shows the VTHfeatures a very fast shifting process but a slower recovering process. D-mode HEMTs counterpart without Mg contamination demonstrates a negligible VTHshift and hysteresis, proving the VTHinstability is probably due to the ionization of acceptor-like traps in the p-GaN depletion region. Finally, the VTHinstability is verified by a GaN circuit under switching stress. The VTHinstability under different sweeping speed uncovers the fact that the high VTHby conventionally slow DC measurements is probably artificial. The DC VTHshould be high enough to avoid HEMT faulty turn-on.