Influence of Metal on Schottky Barrier Inhomogeneity in Ga₂O₃ Schottky Barrier Diodes

A systematic study of Schottky barriers fabricated on Ga2O3 film is reported. The Schottky barrier heights (SBHs) and current transport mechanisms were estimated through the analysis of current-voltage (I-V), capacitance-voltage (C-V), current-voltage-temperature (I-V-T), and x-ray photoelectron spectroscopy (XPS) measurements. The estimated values of the SBH of Ni varied from 1.01 eV to 1.13 eV depending on the method of analysis. These values are close to the theoretical value derived from the Schottky-Mott relationship. In contrast, for Au, there is a lack of general agreement between SBH values determined by different methods. This appears to hint at the presence of spatial inhomogeneities affecting the estimated SBH values to varying degrees depending on the method of analysis. The dependence of the SBH and carrier transport mechanism on metals suggests that metals/Ga2O3 interfaces are not fully pinned, and this fact can affect device reliability.