Self-accelerating oxidation at oxide/Si(111) interfaces studied by real-time photoelectron spectroscopy

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

The self-limiting oxidation has been observed in the initial oxidation stage of a few nanometers oxide thickness. We have recently found that the oxidation rate on Si(111)77 surfaces at room temperature is accelerated with an incubation time. In this study, oxidation states, oxide thickness, and strained Si atoms were observed by real-time synchrotron X-ray photoelectron spectroscopy. Oxide thickness increased with increasing O dosage but showed an increase at the dosage of 3.110 L. An additional oxide thickness change was noticed at 4.810 L. It is clear that Si oxidation state starts to increase together with the Si and Si state. Consequently, the good coincidence between the growth of chemical states of Si and oxide thickness suggests that the self-accelerating oxidation is associated with the oxidation-induced strains.