  We report a dramatic current reduction, or a resistance increase, by a few
orders of magnitude of two common-anode Au/Ti/pGaN Schottky junctions annealed
within a certain annealing condition window (600 - 700 oC, 1 - 4 min). Results
from similar common-anode Schottky junctions made of Au/p-GaN, Al/Ti/p-GaN and
Au/Ti/graphene/p-GaN junctions demonstrated that all the three layers (Au, Ti
and p-GaN) are essential for the increased resistance. Raman characterization
of the p-GaN showed a decrease of the Mg-N bonding, i.e., the deactivation of
Mg, which is consistent with the Hall measurement results. Moreover, this
high-resistance junction structure was employed in p-GaN gate AlGaN/GaN HEMTs.
It was shown to be an effective gate technology that was capable to boost the
gate breakdown voltage from 9.9 V to 13.8 V with a negligible effect on the
threshold voltage or the sub-threshold slope.
