10 kV, 39 mΩ·cm²Multi-Channel AlGaN/GaN Schottky Barrier Diodes

Abstract

This work demonstrates multi-channel AlGaN/GaN Schottky barrier diodes (SBDs) with a breakdown voltage (BV) over 10 kV, the highest BV reported in GaN devices to date. The epitaxial structure consists of a p-GaN cap layer and five AlGaN/GaN channels continuously grown on a low-cost 4-inch sapphire substrate. A novel device design is proposed for electric field management, i.e., the p-GaN reduced surface field (RESURF) structure, which balances the net charges in the multi-channel at reverse biases. The SBD with a 98- $\mu \text{m}$ anode-to-cathode length ( ${L}_{{\text {AC}}}{)}$ shows a BV of 9.15 kV and a specific on-resistance ( ${R}_{ \mathrm{\scriptscriptstyle ON}}{)}$ of 29.5 $\text{m}\Omega \cdot $ cm2, rendering a Baliga's figure of merit (FOM) of 2.84 GW/cm2. The SBD with a 123- $\mu \text{m}~{L}_{{\text {AC}}}$ shows a BV over 10 kV and a ${R}_{ \mathrm{\scriptscriptstyle ON}}$ of 39 $\text{m}\Omega \cdot $ cm2, which is 2.5-fold lower than the ${R}_{ \mathrm{\scriptscriptstyle ON}}$ of the state-of-the-art 10-kV SiC junction barrier Schottky diodes. The Baliga's FOMs of our 4.6-10 kV GaN SBDs well exceed the SiC unipolar limit. These results show the great promise of GaN for medium- and high-voltage power electronics.