Characterization of dielectric properties of ultrathin SiO2 film formed on Si substrate

The dielectric constant of ultrathin (0.55–7.96 nm) SiO2 films formed on Si(0 0 1) substrates was characterized in terms of the modified Auger parameter, α′. The α′ values for Si atoms were found to shift by about 0.7 eV for ultrathin SiO2 films compared with thick SiO2 films. This shift is apparently caused only by a change in the electrostatic screening energy originating from the dielectric discontinuity between the bulk dielectric constants of SiO2 and Si at the SiO2/Si interface. This indicates that the bulk dielectric constant also holds for ultrathin SiO2 films.