A capacitance-based methodology for work function extraction of metals on high-κ

This letter presents a methodology to accurately extract the work function of metal electrodes on high-kappa dielectrics with various charge distributions. A mathematical analysis including sources of errors were used to study the effect of charge distribution in gate dielectric stacks on the flatband voltage of the device. The calculations are verified by experimental results obtained for Ru-Ta alloys on HfO2 and SiO2 gate dielectric stacks. It is shown that accounting for the appropriate charge model is imperative for accurate calculation of workfunction on high-kappa/SiO2 gate dielectric stacks.