White-light spectral interferometric technique to measure a nonlinear phase function of a thin-film structure

[摘要] We present a new two-step white light spectral interferometric technique to measure a nonlinear phase function of a thin-film structure The technique is based on recording of channeled spectra at the output of a Michelson interferometer and their processing by using a windowed Fourier transform to retrieve the phase functions First the phase function including the effect of a thin-film structure is retrieved Second the structure is replaced by a reference sample of known phase change on reflection and the corresponding phase function is retrieved From the two functions the nonlinear phase function of the thin-film structure is obtained The feasibility of this simple method is confirmed in processing the experimental data for a SiO2 thin film on a Si wafer of known optical constants Four samples of the thin film are used and their thicknesses are determined The thicknesses obtained are compared with those resulting from reflectometric measurements and a good agreement is confirmed (C) 2010 Elsevier B V All rights reserved

[发布日期] 2010-12-15

[关键词] Spectral interferometry;Michelson Interferometer;Thin film;Thickness;Phase change on reflection;Nonlinear phase function