4-kV and 2.8- -cm2 Vertical GaN p-n Diodes With Low Leakage Currents

There is great interest in bulk GaN-based power electronics devices for applications requiring breakdown voltages greater than 3.3 kV. In this letter, the vertical GaN p-n diodes fabricated on improved bulk GaN substrates demonstrating low leakage currents (<;10 nA) and avalanche breakdown are discussed. The device layers are grown by metal-organic chemical vapor deposition on low defect density (10⁴ cm^-2) bulk GaN substrates with improved quality and specifications that are uniquely suitable for power electronic device applications. The measured devices show breakdown voltages larger than 4 kV with an area differential specific ON-resistance (R_sp) of less than 3 mΩ-cm². Applications that would require such breakdown voltages, include ship propulsion, rail, wind, uninterruptable power supplies, and the power grid.