High breakdown voltage p-n diodes on GaN on sapphire by MOCVD

In order to achieve high breakdown voltage in GaN vertical power devices, low threading dislocation density and low background carrier concentration is required. This work demonstrates a decrease in the background carrier concentration and threading dislocation density (TDD) with an increase in the thickness of un-intentionally doped (UID) GaN grown on sapphire. p-n diodes grown and fabricated on this epi, using 4.8 mu m UID GaN, showed a breakdown voltage of 730 V, breakdown field of 1.75 MV cm(-1) and an on-resistance of 5.1 m Omega cm(2). The figure of merit (FOM), V-BR(2)/R-ON, thus obtained is approximately 105 MW cm(.)(-2) This is the highest reported FOM value for p-n diodes on GaN on sapphire or Si. Lowering the carrier concentration and dislocation density is thus shown to be critical for achieving high breakdown voltages on GaN on sapphire. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim