Reflection of light in a long-wavelength approximation from an N-layer system of inhomogeneous dielectric films and optical diagnostics of ultrathin layers. II. Transparent substrate

摘要

The reflection of linearly polarized electromagnetic plane waves from an N-layer system of inhomogeneous, dielectric films on a transparent, homogeneous substrate is investigated in the long-wavelength limit. Approximate formulas are obtained for changes in the reflectance of s- or p-polarized light and in the ellipsometric angles that are caused by a multilayer, thin-film system. An analysis of the influence of a multilayer, ultrathin surface film on the reflectance of p-polarized light at the Brewster angle is carried out. All approximate analytical results are correlated with the exact computer solution of the reflection problem for a multilayer system of inhomogeneous films. The possibilities are discussed of using the obtained approximate expressions for resolving the inverse problem of ultrathin dielectric films on transparent substrates. Novel options are developed for determining the parameters of ultrathin films by integrating differential reflectance and ellipsometry. (C) 2004 Optical Society of America.