Electrical characteristics of molybdenum Schottky contacts on n-type GaN

The Schottky barrier heights of molybdenum (Mo) on n-GaN were investigated as a function of annealing temperature by current-voltage (I-V) and capacitance-voltage (C-V) techniques. The Schottky barrier height of the as-deposited Mo/n-GaN was found to be 0.81 eV (I-V) and 1.02 eV (C-V), respectively. However, both measurements indicate that the barrier height slightly decreases upon annealing at 400°C for 1 min in nitrogen ambient. The barrier height of Mo/n-GaN Schottky contacts at 400°C was determined to be 0.74 and 0.92 eV, respectively. Further, an increase in annealing temperature up to 600°C, decreased the barrier height to 0.56 and 0.73 eV. The Mo Schottky contact was also shown to be fairly stable during annealing at 400°C.