High-transparency Ni/Au Ohmic contact to p-type GaN

Tu this study, a very thin Ni / Au bi-layer metal film was prepared by electron beam evaporation and thermal alloying to form Ohmic contact on p-type GaN film. After thermal alloying, the current-voltage (I - V) characteristic of Ni / Au contact on p-type GaN film exhibited Ohmic behavior. The Ni / Au contacts showed a specific contact resistance of 1.7x10(-2) Omega-cm(2) at an alloying temperature of 450 degrees C. In addition, the light transmittance of the Ni / Au (2 nm/ 6 nm) bi-layer on p-type GaN was measured to be around 85% at 470 nm light wavelength. These results suggest that a suitable metallization technology for the fabrication of light emitting devices can be achieved.