Depth profiling of inhomogeneous layers by ellipsometry

Abstract

The inverse problem of ellipsometry for inhomogeneous layers is formulated in terms of a nonlinear operator equation. The Newton-Gauss method is implemented to develop an iterative numerical procedure for its solution. The algorithm is capable to retrieve continuous depth profiles of optical and some structural parameters of the layer from experimental ellipsometric data without prior knowledge about the concrete mathematical function describing their depth variation. The linear inverse theory is employed to provide an estimation of the error variance and the reliability of the calculated results. A particular case of damage depth profile determination of 40 keV Ge + implanted silicon is considered. The effectiveness and the reliability of the method calculations are demonstrated using both simulated and experimental spectroellipsometric data.