Low resistance nonalloyed Ni/Au Ohmic contacts to p-GaN irradiated by KrF excimer laser

摘要

A specific contact resistance of 8.9 x 10~(-5) Ω cm~2 was obtained for a Ni/Au Ohmic layer on the KrF laser-irradiated p-GaN. It was found that laser irradiation increases the hole concentration from 4.1 x 10~(17) to 9.7 x 10~(17) cm~(-3) by removing hydrogen atoms from p-GaN layer. The native oxide was also removed as evidenced by the Ga 2p peak shift and the decrease in the intensity of O 1s peak in the x-ray photoelectron spectra. The formation of a low resistance is attributed to the increase in the hole concentration and the removal of native oxide from p-GaN by laser irradiation.