Structural and electrical properties of Au and Ti/Au contacts to n-type GaN

Au and Ti/Au layers were deposited on n-GaN. The samples were annealed at 400, 700 and 900 °C for 10 min in vacuum. The contacts were rectifying up to 700 °C and the highest Schottky barrier height of 1.07 eV was obtained for an Au single layer by current–voltage measurements. A binary phase of Au2Ga was identified at the interface of the n-GaN/Ti/Au contact after annealing at 900 °C. The formation of Ti2N and TiN (twin) phases epitaxially grown on GaN was also observed in the same contact as well as some gold diffusion into the topmost region of the GaN epilayer.