Formation of high quality ohmic contacts to p-GaN using metal/transparent conducting oxides

We report on promising Ni/transparent conducting oxides for producing high quality ohmic contacts to p-GaN. It is shown that the contacts annealed at 450-600/spl deg/C for 2 min in air ambient result low specific contact resistances of 10/sup -5/-10/sup -6/ /spl Omega/cm/sup 2/. Based on the X-ray photoemission spectroscopy and Auger electron spectroscopy results, ohmic formation mechanisms are described.