Physical properties of SIO2 thin films obtained by anodic oxidation

The article presents a spectroscopic study using the techniques of ellipsom etry and infrared (IR) absorption spectroscopy of the chemical bonding in s ilicon oxide thin films grown by the anodic oxidation of Si at room tempera ture. 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, w hile the frequency of the dominant IR active bond-stretching vibration at a bout 1075 cm(-1) follow an inverse trend having a maximum in the case of ox ide films processed for 7 min. Interpretation of variation of the anodic Si O2 optical parameters was performed on the basis of force constant models f or 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]. T ransitions in density and internal structure of anodic silicon oxide thin l ayers obtained at different anodization times were confirmed using Atomic F orce Microscopy technique. (C) 1999 Elsevier Science B.V. All rights reserv ed.