Vertical GaN junction barrier schottky diodes by Mg implantation and activation annealing

Abstract

Vertical GaN Junction barrier Schottky (JBS) diodes are fabricated on hydride vapor phase epitaxy (HVPE) GaN substrates. The p-type JBS gridded regions were formed by selective area doping by Mg ion implantation followed by an activation anneal. Implantation was performed into a 10 μm thick unintentionally doped GaN layer grown by metal organic chemical vapor deposition (MOCVD). Evaporating Pd/Au formed the anode contacts and the cathode was formed of Ti/Al/Ni/Au. Activation of the Mg-implanted GaN was achieved by implementing a three part process, which includes: 1) capping the GaN surface with sputtered AlN, 2) annealing in a 350 PSI nitrogen overpressure environment, and 3) performing a multicycle rapid thermal anneal (MRTA) with a peak temperature of 1350 °C. In addition to the JBS structures, Schottky barrier diodes (SBDs) and PiN diodes were also fabricated.