Growth and interfacial properties of atomic layer deposited Al0.7Ti0.3O y high-k dielectric on Ge substrate

Growth and interfacial properties of atomic layer deposited Al0.7Ti0.3O y on Ge have been investigated as a potential high-k gate dielectric for future Ge-based metal oxide semiconductor devices. A sandwich structure of Al2O3/TiO2 stack is proposed for Al2O3/TiO2 intermixing and high-k/Ge interfacial passivation. The film thicknesses and interface microstructure are characterized by spectroscopy ellipsometry and high-resolution transmission electron microscopy. X-ray photoelectron spectrometry is used to analyze the chemical composition and bonding states, and to reveal the band alignment of high-k/Ge heterojunctions. Metal-oxide-capacitors are formed by depositing aluminum electrodes to perform capacitance–voltage measurements for electrical characteristics. All evidences show a positive prospect of employing atomic layer deposited Al0.7Ti0.3O y as high-k gate dielectric for future Ge-based devices.