title: Oxidation at the Si/SiO2 interface: influence of the spin degree of freedom.
abstract: We show, using first-principles spin-polarized total-energy calculations, that depending on the spin configuration of the system, the reaction of an O2 molecule with a Si-Si bond in a suboxidized region might result either in a peroxy linkage defect (for a singlet spin state) or in a perfect Si-O-Si bond plus an interstitial O atom (for a triplet spin state). Even though the singlet has a lower energy than the triplet configuration, we find a rather small probability for triplet to singlet conversion. Therefore, as the O2 in an SiO2 interstitial site has a triplet configuration, this reaction spin dependence may have a strong influence on the high quality of the Si/SiO2 interface.
authors.affiliation: Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970, São Paulo, SP, Brazil.
authors.forename: W
authors.initials: W
authors.lastname: Orellana
authors.forename: Antônio J R
authors.initials: AJ
authors.lastname: da Silva
authors.forename: A
authors.initials: A
authors.lastname: Fazzio