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 deg. C for 1 min in nitrogen ambient. The barrier height of Mo/n-GaN Schottky contacts at 400 deg. C was determined to be 0.74 and 0.92 eV, respectively. Further, an increase in annealing temperature up to 600 deg. 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 deg. C