The electrical properties and thermal stability of Zr B 2 Schottky contacts deposited on n -type GaN have been studied. As-deposited contacts had a barrier height of 0.80 eV, which decreased to 0.7 eV after annealing at 300 °C, and to 0.6 eV after additional annealing at 400 °C in nitrogen for 20 min. However, the barrier height remained at about 0.6 eV even when the diodes were annealed at 600 °C for 20 min. The Rutherford backscattering spectra of annealed contacts showed no reaction at the Zr B 2 GaN interface. These results make Zr B 2 GaN Schottky contacts attractive for high temperature device applications.