SPATIAL INHOMOGENEITY AND VOID-GROWTH KINETICS IN THE DECOMPOSITION OF ULTRATHIN OXIDE OVERLAYERS ON SI(100)

Oxide layers whose thickness is 4-10 monolayers decompose inhomogeneously through void formation in which the clean surface is exposed. No changes take place in the oxide region during thermal desorption until it is engulfed by the growing voids. The kinetics of void formation has been measured with isothermal and temperature-programmed methods. A strong similarity to kinetic parameters determined for high-temperature reactive scattering of atomic oxygen from Si(100) is found. This suggests that the rate-limiting step in void growth is oxide decomposition at the void perimeter to produce SiO(g).