Thermally stable rhenium Schottky contacts to n-GaN

The barrier heights of Re Schottky contacts to n-GaN were investigated by current-voltage (I-V) and capacitance-voltage (C-V) measurements. Both techniques indicate that the barrier height increases upon annealing at 500°C for 10 min. After this anneal, a barrier height of 0.82 eV and ideality factor of 1.1 are obtained by I-V measurements performed at 150°C. The C-V measurements performed at room temperature reveal a barrier height of 1.06 eV. These barrier heights are stable upon further short term annealing at temperatures as high as 700°C. The Re Schottky contacts were also stable upon prolonged annealing for 24 h at 300°C. The Re/n-GaN Schottky diode was chosen for study because of its anticipated thermodynamic stability against metallurgical reactions.