10 kV, 39 mΩ·cm2 Multi-Channel AlGaN/GaN Schottky Barrier Diodes

Abstract

This work demonstrates multi-channel AlGaN/GaN Schottky barrier diodes (SBDs) with a breakdown voltage (<italic>BV</italic>) over 10 kV, the highest <italic>BV</italic> 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-<inline-formula> <tex-math notation= LaTeX >$\\mu \\text{m}$ </tex-math></inline-formula> anode-to-cathode length (<inline-formula> <tex-math notation= LaTeX >${L}_{{\\text {AC}}}{)}$ </tex-math></inline-formula> shows a <italic>BV</italic> of 9.15 kV and a specific on-resistance (<inline-formula> <tex-math notation= LaTeX >${R}_{ \\mathrm{\\scriptscriptstyle ON}}{)}$ </tex-math></inline-formula> of 29.5 <inline-formula> <tex-math notation= LaTeX >$\\text{m}\\Omega \\cdot $ </tex-math></inline-formula>cm², rendering a Baliga’s figure of merit (FOM) of 2.84 GW/cm². The SBD with a 123-<inline-formula> <tex-math notation= LaTeX >$\\mu \\text{m}~{L}_{{\\text {AC}}}$ </tex-math></inline-formula> shows a <italic>BV</italic> over 10 kV and a <inline-formula> <tex-math notation= LaTeX >${R}_{ \\mathrm{\\scriptscriptstyle ON}}$ </tex-math></inline-formula> of 39 <inline-formula> <tex-math notation= LaTeX >$\\text{m}\\Omega \\cdot $ </tex-math></inline-formula>cm², which is 2.5-fold lower than the <inline-formula> <tex-math notation= LaTeX >${R}_{ \\mathrm{\\scriptscriptstyle ON}}$ </tex-math></inline-formula> 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.