Vertical GaN Junction Barrier Schottky Diodes

Abstract

Vertical GaN junction barrier Schottky (JBS) diodes are demonstrated. The JBS p-type grid was formed by Mg-implantation into a 10 μm thick unintentionally doped GaN homoepitaxial drift layer, grown by metal organic chemical vapor deposition (MOCVD). Then, symmetrical multi-cycle rapid thermal annealing (SMRTA) repaired implantation damage and activated the Mg ions. This process includes deposition of an AlN capping layer, annealing in a nitrogen overpressure, and rapid heating and cooling pulsed annealing. In addition, PiN diodes and Schottky barrier diodes (SBDs) were fabricated on the same substrate for comparison. The JBS diode demonstrates forward conduction characteristics dominated by the Schottky barrier (turn-on voltage ∼0.5 V), and reverse breakdown voltage comparable to the PiN diode (−610 V).