Optical and magneto-optical spectroscopic ellipsometry of thin layers and nanostructures

Abstract

This work is revolving around ellipsometry and its applications in magneto-optics. Ellipsometry is particularly attractive for its suitability for insitu measurements and remarkable sensitivity to minute inter-facial effects, such as the formation of sub-mono-layer of atoms or magneto-optical (MO) effect. Special attention is given to ellipsometric setups with photo-elastic modulator (PEM) that are favored for its high signal to noise ratio. Common way of obtaining equations for analysis of spectroscopic data is a direct derivation from Jones or Mueller matrices of the system for each configuration separately. In spite of its various advantages general equation of ellipsometric setup are not being used. For this reason general scalar equations for PEM (photo-elastic modulator) based ellipsometric measurements are derived here that allow easy calculation of each component’s imperfection influence on the results as well as quick insight to all configurations possible. Along with general equation a simplification to Jones Formalism that optimizes numerical calculation is proposed. The spectral magneto-optical measurements of polar, longitudinal and transverse Kerr effect are analyzed with photo-elastic and Faraday cell modulation. Based on the general equation a nulling method for MOKE (magneto-optical Kerr Effect) measurements is calculated and experimentally verified that offers above average precision in desired region of measurement and reduces moving parts to a single branch of the measurement setup further improving noise cancellation possibilities. The trade-off of the proposed method is slightly more complicated nulling procedure. Furthermore an automatic calibration of spectral MOKE measurement setup was designed, programed and applied. For simulation and data analysis a Yeh formalism based program was developed with few applications presented here.