Chemical Bonds at and Near the SiO₂/Si Interface

Abstract

The concept of local electronegativity defined by Lucovsky1) was modified and applied to the study of the chemical bonds at and near the SiO2/Si interface. Even for a flat interface and no Si-Si bond in the oxide film, chemical bonds different from those in the bulk are found to exist not only at the interface, but also near the interface. The local electronegativities of silicon and oxygen atoms change their magnitudes within 1 nm of the interface.

Si(001) Surface Layer-by-Layer Oxidation Studied by Real-Time Photoelectron Spectroscopy using Synchrotron Radiation

“…Therefore, the HBC and LBC components are mainly ascribed to O atoms in the SiO 2 network and at the SiO 2 /Si interface, respectively, which have Si-O-Si bond configurations at any site. 35,49,50) The O atoms present at the SiO 2 /Si interface have Si atoms as the second nearest-neighbor atoms (O 3 Si-O-Si O 3Àx Si xþ1 : x ¼ 0, 1, and 2) and therefore can obtain a larger charge transfer than the O atoms in the SiO 2 network (O 3 Si-O-SiO 3 ), resulting in a chemical shift of O 1s to a lower binding energy side, in agreement with the abovementioned assignment of the HBC and LBC components.…”

Metastable ultrathin crystal in thermally grown SiO2 film on Si substrate

“…This indicates that the crystalline transition layer is epitaxially grown and that its vertical period is twice that of the silicon crystal, which is consistent with the X-ray diffraction results. On the basis of this experimental result, we assume a pseudocristobalite structure model, 24 as shown in Fig. 2.…”

Excess Si atoms near the pyrolytic-gas-passivated ultrathin silicon oxide/Si(100) interface

“…6, N Si(excess) was larger than the ideal number density of Si atoms in the stoichiometric SiO 2 compound in all cases and decreased with decreasing humidity. Such positive N Si(excess) values indicate the existence of a stratified transition-oxide area containing the excess Si atoms near the interface (here, it is also called the transition layer), which originates from the heterogeneity of the microscopic structures of the oxide films because of atomic level distortion, interface roughness, suboxide domain (Si-O x Si 4-x (x ϭ 1-3)) formation, [54][55][56][57] and so on. Although the microscopic structure of this transition layer still cannot be clearly identified, the presence of the excess Si atoms raises the possibility that Si dangling bonds are probably induced near the interface.…”