Structure and electronic states of ultrathin SiO2 thermally grown on Si(100) and Si(111) surfaces

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autor(en): Ley L, Ristein J
Zeitschrift: Applied Surface Science
Verlag: Elsevier
Jahr der Veröffentlichung: 1997
Band: 117/118
Seitenbereich: 32
ISSN: 0169-4332


Abstract

The chemical and electronic structures of ultrathin SiO2 thermally grown on Si(100) and Si(111) have been investigated by using Fourier-transform infrared attenuated total reflection (FT-IR-ATR) and X-ray or ultraviolet excited photoelectron spectroscopy (XPS/UPS), respectively. A red-shift of the p-polarized LO phonon peak observed for oxides thinner than 2 nm indicates that compressively strained Si-O-Si bonds exist near the SiO2/Si interface. The extent of the structural strain induced in the interface region is found to be smaller for SiO2 grown at 1000°C on Si(100) than 1000°C SiO2 on Si(111) or 800°C SiO2 on Si(100). It is also found that, from the onset of the energy loss signal for Ols photoelectrons, the bandgap of the oxides thicker than ∼ 2.3 nm is 8.95 ± 0.05 eV irrespective of the oxide thickness. For oxides thinner than ∼ 2.3 nm, a remarkable increase in the 5-9 eV energy loss signal for O1s photoelectrons is observed. This could be attributed to not only the contribution of suboxides at the interface but also the built-in stress in the interface region which causes the band edge tailing.


FAU-Autoren / FAU-Herausgeber

Ley, Lothar Prof. Dr.
Naturwissenschaftliche Fakultät
Ristein, Jürgen apl. Prof. Dr.
Lehrstuhl für Laserphysik

Zuletzt aktualisiert 2018-07-08 um 15:23