High-resolution O 1s and Si 2p photoelectron spectroscopy using synchrotron radiation was employed to clarify a layer-by-layer oxidation reaction mechanism on a Si(001) surface from the viewpoint of point defect generation due to an oxidation-induced strain at a SiO2/Si interface. The Si β and Siα components in Si 2p3/2 spectra, which are assigned to the first and second strained Si layers, respectively, below the transition layer composed of suboxides, Si1+, Si2+, and Si3+, significantly decrease during the step-by-step temperature increase-enhanced growth of the second oxide layer. Because of the corresponding band bending changes measured using the O 1s peak position, which are caused by defect-related band gap states, the observed decreases in Siβ and Siα components, indicating a decrease in interfacial strain, are induced not only by the structural relaxation of a SiO2 network due to a thermal annealing effect, but also due to the generation of point defects at the SiO2/Si interface. Continuous band bending changes with the growth of the third oxide layer also suggest that the point defects are generated during oxide growth, whereas the Si&beta and Siα components are maintained almost constant. On the basis of the observed interfacial strain and point defect generation changes, the layer-by-layer growth kinetics of the first, second and third oxide layers is discussed using a unified Si oxidation reaction model mediated by point defect generation at the SiO2/Si interface [S. Ogawa and Y. Takakuwa: Jpn. J. Appl. Phys. 45 (2006) 7063].
|ジャーナル||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|出版ステータス||Published - 2007 5 17|
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