Structural, Band And Electrical Characterization Of Beta-(Al0.19ga0.81)(2)O-3 Films Grown By Molecular Beam Epitaxy On Sn Doped Beta-Ga2o3 Substrate

We characterized unintentionally doped beta-(Al0.19Ga0.81)(2)O-3 for its structural, band, and electrical properties by using a variety of material and electrical characterization methods such as atom probe tomography (APT), transmission electron microscope, X-ray photoelectron spectroscopy (XPS), capacitance-voltage measurement, and a temperature dependent forward current-voltage measurement. A 115nm thick beta-(Al0.19Ga0.81)(2)O-3 film was grown by molecular beam epitaxy on Sn doped Ga2O3 substrates. Reciprocal space mapping shows a lattice matched (Al0.19Ga0.81)(2)O-3 layer. Both APT and TEM results confirm a sharp beta-(Al0.19Ga0.81)(2)O-3/beta-Ga2O3 interface. XPS measurements show conduction band offsets of 2.78 +/- 0.25eV and 0.79 +/- 0.25eV between the SiO2/beta-(Al0.19Ga0.81)(2)O-3 and beta-(Al0.19Ga0.81)(2)O-3/beta-Ga2O3 interfaces, respectively. Extracted room temperature Schottky Barrier Heights (SBHs) after zero field correction for Pt, Ni, and Ti were 2.98 +/- 0.25 eV, 2.81 +/- 0.25eV, and 1.81 +/- 0.25eV, respectively. The variation of SBHs with metals clearly indicates the dependence on work function.