Chemical structure of the ultrathin SiO2/Si(100) interface:: An angle-resolved Si 2p photoemission study -: art. no. 205310

The ultrathin SiO2/Si(100) interface has been investigated by extensive high-resolution angle-resolved photoemission measurements of the Si 2p core levels. The polar angle dependence of the Si 2p intensities are measured in detail fur the different suboxide (Si1+, Si2+ and Si3+) components originating from transition layers at the interface. The depth distribution of the different suboxide species is quantitatively analyzed by a simple electron attenuation scheme. It is unambiguously shown that the Si3+ species is distributed over a significantly wider region from the interface, while the Si1+ and Si2+ species exist mostly within the first interfacial layer. A chemically nonabrupt interface is thus clearly supported, and a simple interface model is introduced which is composed of three transition layers.