A novel determination method of thin film optical parameters with least dependence on photometric measurement systematic errors

We present a novel determination method of thin film optical parameters based on partial derivatives selection, which is with least impact of photometric measurement systematic errors on the characterization accuracy of thin film optical parameters. The spectral measurement data used in our numerical simulations are the single wavelength photometric data of P-polarization light measured at different incident angles. It is shown that, under the same level of systematic errors in the measurement data, the deviations of the fitted optical parameters values from real ones in spectral bands with opposite signs of partial derivatives for most incident angles at which measurement data are collected are much smaller than other spectral regions. The theoretical explanations are discussed. It is advisable to select spectrophotometric data from the recommended spectral bands and to remove the dangerous spectral bands according to derivatives information for optical characterization of thin films with best accuracy.