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Considerations of the intermediate oxides via XPS elemental quantitative analysis for the thickness measurements of ultrathin SiO 2 on Si
Author(s) -
Liu Fen,
Zhao Zhijuan,
Zhao Liangzhong,
Wang Hai
Publication year - 2011
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.3671
Subject(s) - overlayer , x ray photoelectron spectroscopy , monolayer , oxide , silicon , work (physics) , analytical chemistry (journal) , materials science , chemistry , nanotechnology , thermodynamics , optoelectronics , metallurgy , physics , nuclear magnetic resonance , chromatography
The thicknesses of intermediate oxides at the interface between ultrathin SiO 2 and Si substrates have been measured via XPS elemental quantitative analysis for some SiO 2 /Si(100) and SiO 2 /Si(111) samples with the silicon oxide thickness less than 2 nm. The measurements involve XPS determination of the Si relative atomic ratio, calculation of Si atomic densities for the intermediate oxide, etc. and then the intermediate oxide thicknesses and the number of monolayers are obtained by referencing the thickness data from two international comparisons for these samples. The results show that the thickness of the intermediate oxides is in the range 0.14–0.16 nm with an average value of 0.15 nm. The number of monolayers for the intermediate oxides at the interface is less than one monolayer with an average value of 0.60. In the present work, there are a series of approximations. By making these approximations many parameters, including L and R 0 , used in the conventional calculation method are removed to give a simpler equation, which is valid when the thicknesses of SiO 2 overlayer and the intermediate oxides are very small. This, therefore, appears to be a simple and quick method to obtain approximate oxide thicknesses of modest accuracy. The present work does not in any way replace or improve on Eqns (2–6) cited in the text. Copyright © 2010 John Wiley & Sons, Ltd.