Low ON-State Resistance Normally-OFF AlGaN/GaN MIS-HEMTs With Partially Recessed Gate and ZrO ₓ Charge Trapping Layer

Novel normally-OFF AlGaN/GaN MIS-high electron mobility transistors (HEMTs) with a ZrO x charge trapping layer are proposed. The deposition of the ZrO x charge trapping layer on the partially recessed AlGaN in conjunction with the Al2O3 gate dielectric has been accomplished. The developed MIS-HEMTs exhibit a threshold voltage of 1.55 ± 0.4 V and a maximum drain current of 730 ± 6 mA/mm, while associated low ON-resistance of $7.1~\pm ~0.2~\Omega \cdot $ mm, for a gate to drain separation of 3 $\mu \text{m}$ . The TCAD simulation results are presented to explore the charge trapping and de-trapping behaviors. Moreover, the devices exhibit a high breakdown voltage. The results indicate the merits of employing ZrO x charge trapping layer to realize the normally-OFF GaN devices with low ON-state resistance.