Improvements in the Annealing of Mg Ion Implanted GaN and Related Devices

The activation of ion implanted p-type dopants in GaN is notoriously difficult as the extremely high temperatures required to activate implanted Mg also damage the GaN crystal. In this paper, we present refinements to our novel annealing process (symmetric multicycle rapid thermal annealing) to reduce surface damage and contamination responsible for elevated leakage currents and non-ideal diode behavior. Furthermore, we apply the technique to Mg-implanted bulk GaN substrates to enable vertical power device structures, demonstrating rectifying p-i-n junctions. In addition, the technique was applied for edge termination in both p-i-n and Schottky barrier diodes, realizing floating guard ring and junction termination extension structures. The processes demonstrated here represents a key enabling step for future GaN-based power devices.