Spectroscopic ellipsometry of TiO2 layers prepared by ion-assisted electron-beam evaporation

Single layer TiO2 films deposited on BK7 glass substrates by the ion-assist ed electron-beam evaporation technique have been characterized by phase mod ulated spectroscopic ellipsometry. The ellipsometry spectra were recorded i n the wavelength range of 300-1000 nm. The measured spectra were then fitte d with theoretically simulated curves generated assuming different model sa mple structures. Analyses were carried out separately in three different wa velength regimes, the transparent regime with no dispersion of refractive i ndex (650- 1000 nm), the transparent regime with dispersion of refractive i ndex (400-650 nm) and the absorbing regime (300-450 nm). Modeling has been attempted with both homogeneous and inhomogeneous sample structures. For th e inhomogeneous structure, both linear and non-linear variation of refracti ve index along the depth of the sample were used. Refractive indices of the samples were determined separately from the best-fit ellipsometric data in the above three wavelength regimes. Finally, variation of refractive index with the variation in ion beam currents has been studied. (C) 2000 Elsevie r Science S.A. All rights reserved.