We present an investigation of the electrical characteristics of plasma exp
osed GaN. The specific contact resistance of ohmic contacts fabricated on G
aN after argon plasma bombardment for 2.5 min at. 0.03 W/cm(2) are measured
to decrease by a factor of 4 compared to the unetched surface. Gold has be
en found to be the best material for GaN Schottky diode. A study of the ele
ctrical performance of diodes fabricated on plasma exposed GaN has been und
ertaken. To compare the effect of the chemical versus physical factors, as
well as the role played by the ion mass of the etchant species during the e
tching process on diode behavior, GaN surfaces have been exposed to Ar, N-2
, as well as SF6+N-2 plasmas before diode fabrication. Our data indicate th
at a plasma with low ion mass etchant species or a dominant chemical mechan
ism of etching with a high etch rate creates less surface damage. The use o
f a SF6+N-2 plasma should be possible for GaN transistor gate recessing. (C
) 2000 American Vacuum Society. [S0734-211X(00)07306-6].