Role of molecularly-adsorbed O on oxidation at SiO/Si(001) interface

Tsuda, Yasutaka   ; Yoshigoe, Akitaka ; Ogawa, Shuichi*; Sakamoto, Tetsuya*; Takakuwa, Yuji

In Si dry oxidation, the SiO growth proceeds at the SiO/Si interface after the O molecule adsorbs the SiO surface and diffuses through the SiO layer. A unified Si oxidation reaction model mediated by point defect generation, where carrier trapping at the vacancy site plays a crucial role in promoting O dissociative adsorption at the SiO/Si interface, was proposed for the Si dry oxidation. The model suggested two reaction paths of Loop A (single step, fast) and Loop B (double step, slow), but it was unclear how the branching of the two loops occurs. In this study, we investigated the oxidation reaction kinetics on n-Si(001) by X-ray photoemission spectroscopy (XPS) and a supersonic O molecular beam (SOMB) in order to clarify the origin of the branching of the two reaction loops.