Optical diagnostics of nanometer dielectric films by combining ellipsometry and differential reflectance

OPTICAL DIAGNOSTICS OF NANOMETER DIELECTRIC FILMS BY COMBINING ELLIPSOMETRY AND DIFFERENTIAL REFLECTANCE 

Institute of Physics, University of Tartu, 51014 Tartu, Estonia E-mail peep fl.tartu.ee 

The effect of nanometer dielectric films on the ellipsometric parameters and reflectance of linearly polarized light is investigated within the framework of the perturbation theory. The novel approach is developed for simultaneous determining the thickness and dielectric constant of nanometer-scale films by the differential reflectance and ellipsometric measurements. 

The purpose of this paper is to study the differential ellipsometric and reflectance characteristics of an ultrathin dielectric film in the long-wave limit and to take a further look for determining the parameters of nanoscale films on the basis of first- and second-order approximate expressions for reflection characteristics. 

We consider the reflection of s- and p-polarized time-harmonic electromagnetic plane wave in an ambient medium of real dielectric constant from a plane-parallel layer medium consisting of a semi-infinite absorbing substrate with dielectric constant e, = , + and an ultrathin dielectric film with thickness d, A and real dielectric constant. We assume that all media are uniform, isotropic and nonmagnetic. Ultrathin dielectric layers are considered 

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