Low-resistance ohmic contacts to p-type GaN

Low-resistance ohmic contacts with high transparency to p-type GaN have bee n developed by oxidizing Ni/Au thin films. Compared to the metallic Ni/Au c ontacts, the oxidized Ni/Au contacts exhibited lower specific contact resis tance and much improved transparency. The transparency was from 65% to 80% in the wavelength of 450-550 nm. A specific contact resistance below 1.0 X 10(-4) Ohm cm(2) was obtained by oxidizing Ni(10 nm)/Au(5 nm) on p-type GaN . The mechanism of low-resistance ohmic contact could be related to the for mation of NiO. (C) 1999 American Institute of Physics. [S0003-6951(99)04809 -3].