Application of group electronegativity concepts to the effective work functions of metal gate electrodes on high-κ gate oxides

The empirical relationship between electronegativity and effective work function is applied to a diverse set of multi-element electrode materials on hafnium dioxide (HfO2) gate dielectrics. To accommodate the multi-element nature of metal gate electrodes the group electronegativity of the metal was calculated from the geometric mean of electronegativity with respect to the volume stoichiometry of the constituent elements. Results show a reasonable linear fit that provides guidance for the selection of metal gate electrodes on HfO2. The group electronegativity concept is also extended to work function engineering via dielectric capping materials. The electronegativity trends provide insight into the relative charge neutrality levels of candidate dielectric capping materials and their subsequent impact on the metal effective work function.