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

Abstract

AbstractThermal annealing effects on the electrical and structural properties of Ni/Mo Schottky contacts on n‐type GaN have 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 °C 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.