Energy band line-up of atomic layer deposited Al2O3 on β-Ga2O3

Electrical properties of atomic layer deposited Al2O3/β-Ga2O3 interface were investigated. We determined the conduction band offset and interface charge density of Al2O3/β-Ga2O3 interface by analyzing the capacitance-voltage characteristics. The conduction band offset at the Al2O3/β-Ga2O3 interface was found to be 1.7 eV. A large positive sheet charge density of 3.6 × 1012 cm−2 is induced at the Al2O3/β-Ga2O3 interface, which caused a non-zero field of 0.7 MV/cm in the Al2O3 under flat-band conditions in the β-Ga2O3. The forward current-voltage characteristics were found to be related to trap-assisted tunneling.