Physical properties of SIO2 thin films obtained by anodic oxidation

The article presents a spectroscopic study using the techniques of ellipsometry and infrared (IR) absorption spectroscopy of the chemical bonding in silicon oxide thin films grown by the anodic oxidation of Si at room temperature. In the anodization time range of 1-30 min, the variation in the index of refraction n presents a minimum in the case of films growth at 7 min, while the frequency of the dominant IR active bond-stretching vibration at about 1075 cm(-1) follow an inverse trend having a maximum in the case of oxide films processed for 7 min. Interpretation of variation of the anodic SiO2 optical parameters was performed on the basis of force constant models for the vibrational properties [G. Lucovsky, M.J. Manitini, J.K. Srivastava, E.A. Irene, J. Vac. Sci. Technol., B5(2) (1987) 530; P.N. Sen, M.F. Thorpe, Phys. Rev., B15(1977) 4030; G. Lucovsky, Philos. Mag., B39 (1979) 513]. Transitions in density and internal structure of anodic silicon oxide thin layers obtained at different anodization times were confirmed using Atomic Force Microscopy technique. (C) 1999 Elsevier Science B.V. All rights reserved.