Effective work function of NiSi/HfO2 gate stacks measured with X-ray photoelectron spectroscopy

A method to measure an effective work function, WFeff, of a metal electrode in contact with particular dielectric in a metal–oxide–semiconductor stack is proposed by in situ monitoring core level binding energy shifts of dielectric constituents upon deposition of an ultrathin metallic layer on top. The proposed method is utilized to measure relative changes in WFeff between Ni and NiSi electrodes in contact with HfO2, as well as to investigate the role of Sb and Ti δ-layers at NiSi/HfO2 interface.