Analysis of temperature dependent forward characteristics of Ni/((2)over-bar01) β-Ga2O3 Schottky diodes

In this paper, the temperature dependence of the turn-on characteristics of Schottky barrier diodes fabricated on ((2) over bar 01) oriented n-type beta-Ga2O3 is reported. The barrier height (q Phi(bn)) and ideality factor (n) for Ni-beta-Ga2O3 was found to be 1.08 +/- 0.05 eV and 1.19 respectively at room temperature. The effective Richardson constant (A**) is determined to be 42.96 A cm(-2) K-2, in close agreement with the theoretical value. At low temperatures (85-273 K), the current-voltage characteristics reveal a strong temperature dependence of Schottky barrier heights and ideality factors and a corresponding deviation from the barrier height extracted from capacitance-voltage measurements. A detailed analysis is presented, which suggest that these effects can be attributed to a large barrier inhomogeneity at metal/beta-Ga2O3 interfaces, possibly resulting from interfacial defects, which can be modeled using a potential fluctuation model.