Engineering chemically abrupt high-k metal oxide/silicon interfaces using an oxygen-gettering metal overlayer

An approach for engineering the thickness of the SiO ₂-based interfacial layer (IL) between metal oxide films and silicon after deposition of the metal oxide layer was described. The removal of the low-k interface layer was also investigated using electron microscopy and spectroscopic techniques. It was observed that a Ti overlayer, that exhibited a high oxygen solubility, gettered oxygen from the interface layer through an interposed metal oxide high-k layer and thus decomposing SiO ₂ and reducing the interface layer thickness. An enhancement of the gate capacitance density, while retaining low leakage current densities, was observed from the interface-engineered high-k gate stacks.