Relationship between optical dielectric constant and XPS relative chemical shift of 1s and 2p levels for dielectric compounds

We find a new relationship between the optical dielectric constant of Al dielectric films and their chemical shifts measured by X- ray photoelectron spectroscopy (XPS). We measure the difference between core-level binding energy shift for Al 1s and core-level binding energy shift for Al 2p, Delta E-1s - Delta E-2p, for AlN using high- resolution high- energy synchrotron radiation. We find that Delta E-1s - Delta E-2p correlates well with the optical dielectric constants of Al, AlN, and Al2O3. This is consistent with the case of our previously reported Si compounds. First-principles calculations are performed to determine the mechanism behind the observed correlation.