Structural and electrical properties of Mo/n-GaN Schottky diodes

The electrical and structural properties of molybdenum (Mo) Schottky contact to n-type GaN (4.07 × 10 ¹⁸ cm ^-3) have been investigated before and after annealing at 600 °C. Measurements show that the Schottky barrier height of the as-deposited sample was 0.81 eV (I-V) and 1.02 eV (C-V), respectively. It is shown that when the sample is annealed at 400 °C the Schottky barrier height slightly decreases to 0.74 eV (I- V) and 0.92 eV (C- V), respectively. However, the barrier height degraded to 0.56 and 0.73 eV when the sample was annealed at 600 °C for 1 min in nitrogen ambient. Based on the Auger electron microscopy and X-ray diffraction results, the formation of nitride phases at the Mo/n-GaN interface could be the reason for degradation of Schottky barrier height upon annealing at 600 °C.