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 _GD of 27 μm exhibits a low R _ON of 16.9 Ω∙mm, corresponding to a specific R _ON ( R _ON,SP ) of 6.42 mΩ·cm ² . 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 μs after a 10-ms V _DS -OFF stress. At V _DS-OFF = 1200 V, the ratio of dynamic R _ON to static R _ON is 1.09. The results highlight the superior capabilities of active passivation technique for 1200-V GaN power transistors.