A comparative study of GaN diodes grown by MBE on sapphire and HVPE-GaN/sapphire substrates.

In this paper we report on the fabrication and characterization of GaN diod es (Schottky and p-n junctions) grown by plasma assisted MBE. We observed t hat Schottky diodes improve both in reverse as well as forward bias when de posited on 5 mum thick HVPE n(+)-GaN/sapphire instead of bare sapphire subs trates. These improvements are attributed to the reduction of disloctions i n the MBE homoepitaxially grown GaN. Similar benefits are observed in the r everse bias of the p-n junctions which according to EBIC measurements are a ttributed to the reduction of etch pits in the MBE grown p-GaN.