Schottky diode measurements of dry etch damage in n- and p-type GaN

n- and p-type GaN was exposed to inductively coupled plasma of N-2, H-2, Ar , or Cl-2/Ar, as a function of source power (0-1000 W) and rf chuck power ( 20-250 W). For n-GaN, there was a strong reduction in diode reverse breakdo wn voltage and an increase in forward and reverse currents, while for p-GaN the reverse breakdown voltage increased. These results are consistent with creation of point defects with shallow donor nature that increase the cond uctivity of initially n-type GaN or decrease the conductivity of p-type GaN . Annealing at 750 degrees C under N-2 produced significant recovery of the electrical properties, while wet etch removal of 500-600 Angstrom, of the surface produced a full recovery. For completed n-type mesa diodes exposed to Ar or Cl-2/Ar discharges, the low bias forward currents increased by sev eral orders of magnitude. The exposed surfaces became N-2 deficient in all cases. (C) 2000 American Vacuum Society. [S0734-2101(00)00104-4].