We report the design and development of vertical 1.5 kV GaN p-n diodes that consists of an 8 mu m drift layer and a thin p-GaN/p(+)-GaN layer grown by metal-organic chemical vapor deposition (MOCVD) on a hydride vapor phase epitaxy (HVPE) synthesized GaN substrate. The drift layer has a low doping concentration of similar to 9 x 10(15) cm(-3) and electron mobility similar to 1200 cm(2) Ns at room temperature. The fabricated devices with an optimized guard ring design as edge termination exhibit a breakdown voltage of > 1.5 kV with specific on-resistance of similar to 1.5 m Omega cm(2). The breakdown efficiency of these diodes is over 72 when compared to ideal analytical calculations and over 90 with respect to numerical simulations. Temperature-dependent measurements show that the devices have a positive temperature coefficient suggesting the avalanche breakdown mechanism. These results suggest that these MOCVD grown vertical GaN-on-GaN (HVPE) p-n diodes are promising for low-mid range voltage power switching applications.
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