High-temperature SiO2 decomposition at the SiO2/Si interface

The high-temperature decomposition of thin (approximately 100 A) SiO2 layers on Si(001) under ultrahigh-vacuum annealing conditions has been studied by means of ion scattering and microscopy techniques. SiO2 is removed from the Si surface by the formation and lateral growth of holes in the oxide, exposing regions of atomically clean Si, while the surrounding oxide retains its initial thickness. Surface diffusion of Si inside the holes supplies Si for reaction with SiO2 at the periphery, so that a volatile product (presumably SiO) can be formed. (Author)