In situ ESR observation of interface dangling bond formation processes during amorphous SiO2 growth on Si

We report on the first observation of the processes of formation of interface dangling bond (Pb centers) during amorphous SiO2 thin-film growth on a clean Si(1 1 1) substrate. After initial termination of the surface dangling bonds on the clean surface, rapid formation of Pb centers was observed. Even for a few monolayers of a-SiO2 film (<0.4 nm), the number of Pb centers reached the same order of magnitude as that in thick a-SiO2 films. These results suggest that the interface defect density between Si and a-SiO2 originates statistically from the short-range chemical bonding configurations and not from the long-range accumulation of the structural misfits between the two materials.