High-Performance Ultrathin-Barrier AlGaN/GaN Hybrid Anode Diode With Al₂O₃ Gate Dielectric and In Situ Si₃N₄-Cap Passivation

Abstract

In this article, an ultrathin-barrier (UTB) AlGaN/GaN diode featuring metal–insulator–semiconductor (MIS)-gated hybrid anode (MG-HAD) and in situ Si3N4 cap passivation is demonstrated. The intrinsic turn-on voltage ( ${V}_{\mathrm{ON}}$ ) as low as 0.31 V determined by the as-grown AlGaN-barrier thickness (4.9 nm) is obtained and the ${V}_{\mathrm{ON}}$ exhibits excellent uniformity. More importantly, benefit from the MIS-gated hybrid anode structure, the UTB MG-HAD features good thermal stability in reverse blocking capability. The device delivers a substantially low leakage less than $1~\mu \text{A}$ /mm at −300 V at high temperature (HT) up to 200 °C, which is more than $100\times $ lower than that in the reference device w/o gate dielectric. Besides, the device exhibits respectably improved dynamic characteristics due to the incorporation of in situ Si3N4-cap passivation layer and remote plasma pretreatment (RPP) prior to Al2O3 gate dielectric deposition. The UTB MG-HAD featuring precisely ${V}_{\mathrm{ON}}$ modulation and low reverse leakage is of great interest for power electronic applications.