The formation of interface dangling bonds (Pb centers) during the initial oxidation of a clean Si(111) surface was studied by using an ultra-high vacuum electron-spin resonance technique. Upon oxidizing one or two Si layers, the Pb center density reached 2.5 x 1012 to 3.0 x 1012/cm2. This was the same density as in the case of thick SiO2. This showed that the Pb center density did not originate from the long-range accumulation of the structural stress between two materials, but from the chemical reactions of oxidation within a few Si atomic layers.

In situ ESR Observation of Interface Dangling Bond Formation Processes During Ultrathin SiO2 Growth on Si(111). W.Futako, N.Mizuochi, S.Yamasaki: Physical Review Letters, 2004, 92[10], 105505 (3pp)