Robust Avalanche (1.5 kV, 2 kA/cm2) in Vertical GaN Diodes on Patterned Sapphire Substrate

Abstract

<p>The lack of avalanche capability is a keylimitation of current lateral GaN devices. Despite the reportof avalanche in vertical GaN-on-GaN devices, the high wafercost hinders device commercialization. Here we demon-strate a circuit-level avalanche in vertical GaN diodeson low-cost patterned sapphire substrate (PSS), with theavalanche voltage (1.57 kV) and avalanche current den-sity (>2 kA/cm²) both being the highest reported in GaNdevices on foreign substrates. The PSS enables a lowerdislocation density than conventional sapphire substrateand is employed in high-voltage GaN devices for the firsttime. The avalanche voltage in the circuit test reaches 98%of the parallel-plane limit, further affirming that near-idealavalanche breakdown can be realized on GaN devices onforeign substrates. These results show the promise of theGaN-on-PSS platform for low-cost, robust power devices.</p>