Beneficial effect of La on band offsets in Ge/high-κ insulator structures with GeO2 and La2O3 interlayers

Abstract

Listen

Translate article

The electron energy band alignment between (100)Ge and high-κ oxide insulators (ZrO2,Gd2O3,La2Hf2O7) grown by the atomic beam deposition method is analyzed using photoemission of electrons from the Ge valence band. Formation of a thin GeO2 passivation layer before the high-κ deposition is found to significantly reduce the barrier for electrons. However, when La2O3 is deposited as an interlayer, it strongly reacts with the Ge substrate to form a La–Ge–O germanate at the interface, which is found to retain a high barrier for the carriers in Ge.