Structural and electrical properties of rapidly annealed Ni/Mo Schottky barriers on n-type GaN

Thermal annealing effects on the electrical and structural properties of Ni/Mo Schottky contacts on n-typeGaNhave been investigated by current-voltage (I-V), capacitance-voltage (C-V), Secondary ion mass spectrometer (SIMS), and X-ray diffraction (XRD) techniques. The extracted Schottky barrier height (SBH) of the as-deposited contacts was found to be 0.66 eV (I-V), 0.74 eV (C-V). However, both measurements indicate that the barrier height slightly increases when the contacts are annealed at 300 and 400 °C. Experimental results indicate that high quality Schottky contact with barrier height and ideality factor of 0.75 eV (I-V), 0.96 eV (C-V), and 1.13, respectively, can be achieved under 1 min annealing at 500 ° in nitrogen atmosphere. Further, it is observed that the barrier height slightly decreases upon annealing at 600 °C. The above observations establish that the Ni/Mo contact exhibited excellent electrical characteristics even after thermal annealing at 600 °C. Based on the SIMS and XRD analysis, the formation of gallide phases at the Ni/Mo/n-GaN interface could be the reason for the improvement of SBH after annealing at 500 °C. The above results indicate that the Ni/Mo contact can be promising for metallization scheme for high-temperature device applications.