Impacts of the Oxygen Precursor on the Interfacial Properties of LaxAlyO Films Grown by Atomic Layer Deposition on Ge

Amorphous LaxAlyO films were grown on n-type Ge substrate by atomic layer deposition using O₃ and H₂O as oxidant, respectively. A comparison of the XPS results indicated that a thicker interfacial layer with the component of LaGeOx and GeOx was formed at O₃-based LaxAlyO/Ge interface, causing lower band gap value as well as the conduction band offset (CBO) value relative to Ge substrate for O₃-based LaxAlyO film, with a concomitant degeneration in the interfacial properties. In contrast, for the H₂O-based film, the leakage current of more than one order of magnitude less than that of O₃-based LaxAlyO film was obtained. All the results indicated that H₂O is a more appropriate oxidant for improving the interfacial properties in the atomic-layer-deposited LaxAlyO dielectric on Ge.