Nanoscale Characterization of Chemical and Structural Properties of the Au/(100) β-Ga<inf>2</inf>O<inf>3</inf>Interface

Au/β-Ga2O3Schottky contacts deposited at room temperature via electron-beam evaporation are characterized electrically with current density-voltage (J-V) and capacitance-voltage (C-V) measurements. The ideality factor and Schottky barrier heights measured from J-V and C-V are determined to be 1.32, 1.37 eV, and 1.98 eV, respectively. Due to the peculiarities of the electrical properties of the Au/β-Ga2O3Schottky contacts, scanning transmission electron microscopy (STEM) was performed. High-angle annular dark-field (HAADF)-STEM imaging reveals an inhomogeneous chemical reaction occurred at the metal-semiconductor interface. The reaction is signified by void formation 5-20 nm below the interface, Ga diffusion into Au at the interface, and Ga interstitial diffusion toward the interface. Energy-dispersive X-ray spectroscopy (EDS) mapping shows Ga diffusion into the Au contact region accompanied by a transitional region of 4-5 nm.