HIGH-PURITY OZONE OXIDATION ON HYDROGEN PASSIVATED SILICON SURFACE

High purity ozone was used to oxidize hydrogen passivated Si(111) surf ace. 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 formatio n was reduced to one tenth when the surface was completely covered wit h hydrogen. This reduction rate is very small compared to the reductio n rate for oxygen exposure which is reported to be 10(12). Ozone oxida tion still proceeds on the hydrogen passivated surface where oxygen mo lecule does not adsorb at all. Three backbonds of a Si atom are change d to Si-O-Si bridges simultaneously when ozone oxidation proceeds on t he hydrogen passivated surface.