Abstract In this work, the temperature-dependent parameters of Ni/ β -Ga 2 O 3 Schottky barrier diode (SBD) were analyzed and modeled. The simulation is to elucidate the physical phenomenon behind this temperature dependence. At room temperature, the deviation of SBD parameters from the ideal case is due to the Schottky barrier height ( ϕ B ) inhomogeneity. A model is developed for this inhomogeneity in which an interfacial defected layer (IDL) is formed. Defects (extrinsic states) are related to plasma and Ar atom bombardment used in the confined magnetic field-based sputtering to realize the Ni Schottky contact diffusion in β -Ga 2 O 3 . Ni diffuses, upon annealing, to compensate defects in this IDL. It was found that the Schottky barrier height ( ϕ B ) and threshold voltage V Th decrease with increasing temperature. This decrease is related to intrinsic and extrinsic states (plasma and Ar bombardment). However, the ideality factor ( η ) increases which is related to the series resistance ( R S ) increase. The increase is related to the interfacial layer and nickel resistance increase with increasing temperature.