High purity ozone oxidation on hydrogen passivated silicon surface

High purity ozone was used to oxidize hydrogen passivated Si(111) surface. Initial oxide formation was investigated with X-ray photoelectron spectroscopy. The ozone oxidation was disturbed when the surface was gradually covered with hydrogen and finally the rate of oxide formation was reduced to one tenth when the surface was completely covered with hydrogen. This reduction rate is very small compared to the reduction rate for oxygen exposure which is reported to be 1012. Ozone oxidation still proceeds on the hydrogen passivated surface where oxygen molecule does not adsorb at all. Three backbonds of a Si atom are changed to Si-O-Si bridges simultaneously when ozone oxidation proceeds on the hydrogen passivated surface.