Ni, Pd, and Au Ohmic contacts to p-Al 0.45Ga 0.55N have been examined. We have observed that annealing the contacts in excess of 800°C is required to minimize the contact resistivity. However, the Pd and Au contacts annealed in excess of 700°C, which showed much better transport properties than Ni contacts annealed at the same temperatures, suffered from a rapid photoinduced degradation of both the current-voltage characteristics of the contacts and of the sheet resistance of the p-Al 0.45Ga 0.55N itself. This degradation was greatly reduced by passivating the p-Al 0.45Ga 0.55N surface with a SiN x film. A hypothesis is presented to describe the observed degradation.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)