Effect of interfacial Si oxidation on interface dipoles in HfO2/Si structures

Using an in situ Kelvin probe method to investigate the development of interface dipole layers in HfO2/Si structures during interfacial Si oxidation, we found that the dipole strength is greatest when about one monolayer of Si–O bonds is formed at the HfO2/Si interfaces and that further Si–O bond formation reduces the dipole strength. We discuss the difference between the potential profiles of HfO2/one-monolayer SiO/Si and HfO2/two-monolayer SiO/Si structures by using atomistic interface models taking into account dielectric constant screening. (paper)