Temperature-dependent Schottky barrier parameters of Ni/Au on n-type (001) β-Ga₂O₃ Schottky barrier diode

This study examined the temperature-dependent current-voltage (I–V) characteristics of the Ni/Au Schottky contact to β-Ga₂O₃. The Au/Ni/β-Ga₂O₃ Schottky diode showed a good rectifying behavior. The on-resistance and rectification ratio decreased with increasing temperature, which could be ascribed to the increase in the number of thermally activated electrons. The Au/Ni/β-Ga₂O₃ Schottky diode exhibited the strong temperature-dependence of Schottky barrier parameters, indicating the presence of inhomogeneous Schottky barrier prevailing in the interface between Ni and β-Ga₂O₃. The inhomogeneities were analyzed using thermionic emission with assuming a Gaussian distribution of barrier heights. The results revealed the existence of a double Gaussian distribution of barrier heights in the diode with a transition occurring at 225 K. The modified Richardson plot was evaluated using a Gaussian distribution approach and yielded a Richardson constant closely matching with the theoretical value of β-Ga₂O₃. The density of interface states, extracted using I–V characteristics, increased with decreasing temperature, which could be associated with the thermally-driven restructuring and reordering of the Ni/β-Ga₂O₃ interface state.