Depth and thermal stability of dry etch damage in GaN Schottky diodes

GaN Schottky diodes were exposed to N-2 or H-2 inductively coupled plasmas prior to deposition of the rectifying contact. Subsequent annealing, wet photochemical etching, or (NH4)(2)S surface passivation treatments were examined for their effect on diode current-voltage (I-V) characteristics. We found that either annealing at 750 degrees C under N-2, or removal of similar to 500-600 Angstrom of the surface essentially restored the initial I-V characteristics. There was no measurable improvement in the plasma-exposed diode behavior with (NH4)(2)S treatments. (C) 1999 American Institute of Physics. [S0003-6951(99)04528-3].