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‐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.