Nonlinear O pressure dependence of initial oxide growth on Si(111)77 and Si(001)21 surfaces studied by real-time photoelectron spectroscopy and first-principles calculations

Tang, J.*; 西本 究*; 小川 修一*; 吉越 章隆; 石塚 眞治*; 渡辺 大輝*; 寺岡 有殿; 高桑 雄二*

no journal, , 

The real-time photoelectron spectroscopy using He-I resonance line at Tohoku University and synchrotron radiation at BL23SU, SPring-8 have been carried out to investigate the initial oxide growth kinetics on Si(001)21 and Si(111)77 at room temperature and 873 K. The oxygen uptake curves obtained by UPS showed that the initial oxide growth rate does not increase with increasing O pressure on both Si(001) and Si(111) surfaces, implying that the oxide growth is not limited by the number of O molecules impinging on the surface but governed by the surface reaction of O molecule. Assuming the O pressure dependences is represented by a power-low function of P, n is obtained to be 0.42 for Si(111) and 0.54 for Si(001) at room temperature. Based on the XPS and UPS observations, a surface reaction model for the nonlinear O pressure dependence is proposed.