Electrical effects of plasma damage in p-GaN

The reverse breakdown voltage of p-GaN Schottky diodes was used to measure the electrical effects of high density Ar or H-2 plasma exposure. The near surface of the p-GaN became more compensated through introduction of shallow donor states whose concentration depended on ion flux, ion energy, and ion mass. At high fluxes or energies, the donor concentration exceeded 10(19) cm(-3) and produced p-to-n surface conversion. The damage depth was established as similar to 400 Angstrom based on electrical and wet etch rate measurements. Rapid thermal annealing at 900 degrees C under a N-2 ambient restored the initial electrical properties of the p-GaN. (C) 1999 American Institute of Physics. [S0003-6951(99)00343-5].