X-ray photoelectron spectroscopy study on dielectric properties at gate insulator film/Si interfaces

The authors propose a new method to estimate the local dielectric constant of an ultrathin gate insulator film formed on Si substrates by using X-ray photoelectron spectroscopy (XPS). First the authors measure the difference of core-level binding energy shifts for Si 1s and Si 2p, DeltaE_1s DeltaE_2p, for various Si compounds using high-resolution high-energy synchrotron radiation. the authors find that the DeltaE_1s - DeltaE_2p values are in very good correlation with the dielectric constant values of the Si compounds. Then, using this relation, the authors deduce the local dielectric constant for ultrathin SiO₂ film formed on Si substrates. The results are in good agreement with values predicted by a first-principles calculation