Real time observation of photoelectron spectra for phase transition of Si(111) surface oxidation at high temperature

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

The dynamics of oxidation on Si(001) surfaces has been elucidated by DOS model, in which the SiO desorbed from the surface just as 2D island growth started and no desorption was reported during the Langmuir type adsorption, and a thermal activation of SiO desorption was found during the phase transition. However, the mechanism of SiO desorption during the phase transition on Si(111)-77 surfaces is still far from understanding. In this study, SiO desorption process depends on the temperature and oxygen pressure and the relation between oxygen adsorption and SiO desorption during the phase transition have been investigated by real-time photoelectron spectroscopy. It is suggested that SiO desorption occurs during the high temperature Langmuir-type adsorption. It is proposed to be affected by the substable oxygen adsorption states on the surface in the initial oxidation, which is strongly depends on the temperature and oxygen pressure.