A Π-shaped p-GaN HEMT for reliable enhancement mode operation

This paper presents a TCAD based investigation of virtually fabricated Pi-shaped Gate p-GaN HEMT for reliable enhancement mode operation. A detailed comparison with the Conventional T-Gate counterpart, with a focus towards the trap related dispersive effect reveals the superiority of Pi-shaped Gates P-GaN HEMT for suppressing both the vertical substrate and gate leakage currents, thereby enhancing the breakdown characteristics of the device. A modification of the electric fields, into a stepped profile, demonstrates effective suppression of the leakage through the surface defects, and spillover into GaN buffer, thereby mitigating the trap related dispersive effects. Dispersive effect of the two devices has also been compared using current Slump Ratio (SR) which is lower for Pi-shaped Gate P-GaN HEMT. Further analysis into laterally scaled drain-access regions, demonstrates superiority of Pi-shaped Gates in achieving a reliable thermal operation, and applicability of II-shaped Gate P-GaN HEMT for future RF and High Power applications.