Self-accelerating oxidation on Si(111)77 surfaces studied by real-time photoelectron spectroscopy

Tang, J.*; Nishimoto, Kiwamu*; Ogawa, Shuichi*; Yoshigoe, Akitaka ; Ishizuka, Shinji*; Watanabe, Daiki*; Teraoka, Yuden; Takakuwa, Yuji*

Long-time oxidation on Si(111)77 surfaces at room temperature has been investigated by real-time photoelectron spectroscopy to clarify the mechanism of the interface oxidation. It is found that the oxidation mode gradually transformed from oxygen adsorption on the Si(111)77 surface in the initial stage to SiO amorphous-like oxidation on the Si(001)21 surface in the interface oxidation. The self-accelerating oxidation with a significant increase of oxidation rate occurred during the interface oxidation on the Si(111)77 surface, where the strained Si atoms were obviously generated at the SiO/Si interface. The strains generated at interface layers induce the emission of Si atoms from the interface when strain is over a critical value, which contributes to the interface oxidation due to the reaction activities of both the vacancy sites and emitted Si atoms.