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

In this study, a very thin Ni/Au bilayer metal film was prepared by electro n 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 contac ts showed a specific contact resistance of 1.7 x 10-(2) Ohm cm(2) at an all oying temperature of 450 degrees C. In addition, the light transmittance of the Ni/Au (2 nm/6 nm) bilayer on p-type GaN was measured to be around 85% at 470 nm. These results suggest that a suitable metallization technology f or the fabrication of light emitting devices can be achieved. (C) 1999 Amer ican Institute of Physics. [S0003-6951(99)00816-5].