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Daniel Franta, David Nečas, Ivan Ohlídal, Martin Hrdlička, Martin Pavlišta, Miloslav Frumar, Miloslav Ohlídal

Combined method of spectroscopic ellipsometry and photometry as an efficient tool for the optical characterisation of chalcogenide thin films

Journal of Optoelectronics and Advanced Materials 11 (2009) 1891–1898

The optical characterisation of the As33Se67 and Ge2Sb2Te5 chalcogenide thin films is carried out using the combined method of VASE and SR. This method permits to determine both structural and dispersion parameters describing the thin films exhibiting various defects. The structural model is based on including roughness, overlayers and thickness non-uniformity. The dispersion models are based on parametrisation of the joint density of states. These models, unlike the classical models derived from the Lorentz oscillator model, can describe finite bands which allows to introduce a parameter proportional to the density of electrons. It is shown that this method enables to investigate quantitatively changes in the electronic structure of the materials caused by phase transitions which is demonstrated on the Ge2Sb2Te5. It is shown that the combined method with including true structural and dispersion models is a powerful tool for the optical characterisation of thin films exhibiting disordered structure.

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Citing Articles

  1. Nečas D., Franta D., Ohlídal I., Poruba A., Wostrý P.,
    Ellipsometric characterization of inhomogeneous non-stoichiometric silicon nitride films,
    Surface and Interface Analysis 45 (2013) 1188-1192

Cited Articles

  1. Nečas D., Ohlídal I., Franta D.,
    The reflectance of non-uniform thin films,
    Journal of Optics A: Pure and Applied Optics 11 (2009) 045202
  2. Franta D., Ohlídal I., Buršíková V., Zajíčková L.,
    Modeling of dielectric response of GexSbyTez (GST) materials,
    Physica Status Solidi C 6 (2009) S59–S62
  3. Franta D., Buršíková V., Nečas D., Zajíčková L.,
    Modeling of optical constants of diamond-like carbon,
    Diamond and Related Materials 17 (2008) 705–708
  4. Franta D., Hrdlička M., Nečas D., Frumar M., Ohlídal I., Pavlišta M.,
    Optical characterization of phase changing Ge2Sb2Te5 chalcogenide films,
    Physica Status Solidi C 5 (2008) 1324–1327
  5. Franta D., Ohlídal I., Nečas D.,
    Influence of cross-correlation effects on the optical quantities of rough films,
    Optics Express 16 (2008) 7789–7803
  6. Franta D., Nečas D., Zajíčková L.,
    Models of dielectric response in disordered solids,
    Optics Express 15 (2007) 16230–16244
  7. Franta D., Ohlídal I.,
    Influence of lateral dimensions of the irregularities on the optical quantities of rough surfaces,
    Journal of Optics A: Pure and Applied Optics 8 (2006) 763–774
  8. Franta D., Ohlídal I.,
    Comparison of effective medium approximation and Rayleigh–Rice theory concerning ellipsometric characterization of rough surfaces,
    Optics Communications 248 (2005) 459–467
  9. Ohlídal I., Franta D., Frumar M., Jedelský J., Omasta J.,
    Influence of composition, exposure and thermal annealing on optical properties of As–S chalcogenide thin films,
    Chalcogenide Letters 1 (2004) 1–10
  10. Franta D., Ohlídal I., Frumar M., Jedelský J.,
    Expression of the optical constants of chalcogenide thin films using the new parameterization dispersion model,
    Applied Surface Science 212–213 (2003) 116–121
  11. Franta D., Ohlídal I., Frumar M., Jedelský J.,
    Optical characterization of chalcogenide thin films,
    Applied Surface Science 175–176 (2001) 555–561
  12. Ohlídal I., Franta D., Frumar M., Jedelský J., Navrátil K.,
    Complete optical analysis of amorphous As–S chalcogenide thin films by the combined spectrophotometric method,
    Journal of Optoelectronics and Advanced Materials 3 (2001) 873–878
  13. Ohlídal I., Franta D.,
    Ellipsometry of thin film systems,
    Progress in Optics 41 (2000) 181-282
  14. Franta D., Ohlídal I.,
    Ellipsometric parameters and reflectances of thin films with slightly rough boundaries,
    Journal of Modern Optics 45 (1998) 903–934