The dielectric constant ε of ultrathin (0.55-7.96 nm) SiO2 films formed on a Si(001) substrate was characterized in terms of the modified Auger parameter of Si atoms, α′Si. The α′Si was found to be as much as 0.7 eV higher for an ultrathin (0.68 nm) SiO2 film than for thick SiO2 films. From the observed oxide thickness dependence of α′Si, the ε of ultrathin SiO2 films was estimated by calculating the change in the polarization energy and the change in the electrostatic screening energy originating from dielectric discontinuity at the SiO2/Si interface. The ε of ultrathin (0.68-2.13 nm) SiO2 films was identical to that of bulk SiO2 within ±1%.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2003 5|
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