Abstract

FLORES-CAMACHO, J.M. et al. Lock-in amplifier-based rotating-analyzer spectroscopic ellipsometer with micro-controlled angular frequency. Rev. mex. fis. [online]. 2005, vol.51, n.3, pp.274-283. ISSN 0035-001X.

We report on the development of a full operational rotating analyzer spectroscopic ellipsometer. This instrument employs a phase-sensitive amplifier to process the optical signal as an alternative to Fast Fourier Transform analysis. We describe electronic hardware designed to stabilize the rotation frequency of the analyzer prism as well as to drive the device for the positioning of the polarizer prism azimuth. The ellipsometer allows for dielectric function measurement in the energy range from 1.7-5.5 eV, in both ambient air and Ultra High Vacuum (UHV). UHV measurements can be carried out at a temperature as low as 150 K. To evaluate the ellipsometer performance we present results of the determination of the complex dielectric function of a number of semiconductors, namely, GaSb, GaAs, InGaAs, CdTe and CdHgTe.

Keywords : Ellipsometers; control systems; dielectric function; optical properties of thin films.

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