Demonstration of 1200-V E-Mode GaN-on-Sapphire Power Transistor With Low Dynamic ON-Resistance Based on Active Passivation Technique

This letter demonstrates a 1200-V E-mode GaN-on-sapphire power transistor based on active passivation technique. The active passivation concept utilizes a thin p-GaN layer extending from the p-GaN gate towards near the drain to screen the surface traps. The fabricated active-passivation HEMT (AP-HEMT) with ${L}_{\text {GD}}$ of $27 ~\mu \text{m}$ exhibits a low ${R}_{\text {ON}}$ of $16.9 \Omega \cdot $ mm, corresponding to a specific ${R}_{\text {ON}}$ $({R}_{\text {ON, SP}})$ of 6.42 $\text{m}\Omega \cdot $ cm2. A breakdown voltage (BV) over 2000 V is obtained for the AP-HEMT. Besides, the AP-HEMT showcased excellent dynamic performance due to the surface shielding effect provided by the active passivation. Dynamic ON-resistance was characterized $120 ~\mu \text{s}$ after a 10-ms VDS-OFF stress. At VDS-OFF = 1200 V, the ratio of dynamic ${R}_{\text {ON}}$ to static ${R}_{\text {ON}}$ is 1.09. The results highlight the superior capabilities of active passivation technique for 1200-V GaN power transistors.