Au catalyzed structural and electrical evolution of Ni/Au contact to GaN

Abstract

We investigated the micro-structural and electrical behavior of Ni/Au contacts on GaN(0001) during annealing in N-2 and in air. The formation of a Ni4N phase deteriorates the contact resistivity if annealed in N2. Annealing in air, however, dramatically improves it. The oxidation, by creating, them more energy favorable Ni-O bonds, seems to be the recipe to successfully suppress the formation of Ni4N which otherwise would be enhanced significantly by the presence of Au as a catalyst.