High Performance Vertical GaN-on-GaN p-n Power Diodes With Hydrogen-Plasma-Based Edge Termination

This letter reports the first implementation of a hydrogen-plasma-based edge termination technique (HPET) in vertical GaN p-n power diodes grown on bulk GaN substrates using metalorganic chemical vapor deposition. The device with a 9-mu m-thick drift layer exhibited a high breakdown voltage (V-bd) of 1.57 kV, a low ON-resistance (R-ON) of 0.45 m Omega.cm(2) (or 0.70 m Omega.cm(2) with current spreading considered) and a high Baliga's figure-of-merit (V-bd(2)/R-ON) of 5.5 GW/cm(2) (or 3.6 GW/cm(2)) without passivation or field plate, which are close to the theoretical limit of GaN. This technique enabled a significant reduction in leakage current (similar to 10(6) times at -300 V) and a huge enhancement in Vbd (from similar to 300 V to 1.57 kV). Furthermore, the device showed good forward characteristics with a turn-ON voltage of 3.5 V, an ON-current of similar to 2 kA/cm(2) (or 1.3 kA/cm(2)), an ON/OFF ratio of similar to 10(9), and an ideality factor of 1.4. This work shows the HPET can serve as an effective, low cost, and easy-to-implement edge termination technique for high voltage and high power GaN p-n power diodes.