Ellipsometry-based conductivity extraction in case of phosphorus doped polysilicon

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Abstract

In this work, we investigated a new method for thin films electrical conductivity extraction based on spectroscopic ellipsometry. This has been enabled through the correlation between the films conductivity and their ellipsometric properties. Indeed, it has been demonstrated that numerous ellipsometric fitting-based approaches can provide, in an indirect way, the electrical characteristics of thin films. The study was focused on electrical conductivity, but doping level or carriers’ mobility can also be extrapolated from ellipsometric measurements. Among various possibilities leading to electrical properties extraction, we can cite the extremal values of Ψ and Δ ellipsometric angles, their associated wavelengths, the mean square error and the maximal and minimal reflectivities ratio. Otherwise, the correlation between extrinsic conductivity and ellipsometric parameters evolution has been confirmed in case of low doping levels with particular behavior after annealing. This contactless method has been successfully applied to polycrystalline silicon films deposited on oxidized, p-type monocrystalline substrates, by low pressure chemical vapor deposition technique, and lightly or heavily phosphorus doped by diffusion. The feasibility of the method has been proven in this case, but also in other cases like implanted polysilicon layers or silicon-on-insulator (not included here).

Notes

Acknowledgements

We thank very much Mrs Ester Tooten and Mr. Christian Renaux of ICTEAM-UCL, for the preparation of the samples in the clean room facilities named WINFAB.

References

  1. 1.
    X. Li, L. Li, Z. Ma, J. Lu, A.A. Volinsky, F. Ren, Boron doping effects on microcrystalline silicon film roughness studied by spectroscopic Ellipsom. J. Alloy. Compd. 684, 582–586 (2016)CrossRefGoogle Scholar
  2. 2.
    B. Birouk, D. Madi, Thermal oxidation effect on structural and optical properties of heavily doped phosphorus polycrystalline silicon films. Appl. Phys. A 104(2), 739–748 (2011).  https://doi.org/10.1007/s00339-011-6332-1 CrossRefGoogle Scholar
  3. 3.
    A. Borghesi, G. Tallarida, G. Amore et al., Influence of roughness and grain dimension on the optical functions of polycrystalline silicon films. Thin Solid Films 313314, 243–247 (1998)CrossRefGoogle Scholar
  4. 4.
    M. Modreanu, N. Tomozeiu, M. Gartner, P. Cosmin, Microstructural and optical properties of as-deposited LPCVD silicon films. Thin Solid Films 383, 254–257 (2001)CrossRefGoogle Scholar
  5. 5.
    S.A. Memchout, Y. Bouizem, J.D. Sib, A. Belfedal, A. Kebab, D. Benlakehal, L. Chahed, K. Zellama. Effects of ion bombardment on the structural and optical properties in hydrogenated silicon thin films. Thin Solid Films 594, 138–146 (2015)CrossRefGoogle Scholar
  6. 6.
    T.W. Ng, T.W. Teo, P. Rajendra, Optical surface roughness evaluation of phosphorus-doped polysilicon. Opt. Lasers Eng. 35, 1–9 (2001)CrossRefGoogle Scholar
  7. 7.
    M. Boukezzata, B. Birouk, F. Mandour, D. Bielle-Daspet, Structural and electrical changes in polycrystalline silicon thin films that are heavily in situ boron-doped and thermally oxidized with dry oxygen. Chem. Vap. Depos. 3(No5), 271–279 (1997)CrossRefGoogle Scholar
  8. 8.
    M. Modreanu, M. Gartner, C. Cobianu, B. O’Looney, F. Murphy, Optical properties of silicon thin films related to LPCVD growth condition. Thin Solid Films 450, 105–110 (2004)CrossRefGoogle Scholar
  9. 9.
    H. Reisinger, Minimization of errors in ellipsometric measurements. Solid State Electron. 35(3), 333–344 (1992)CrossRefGoogle Scholar
  10. 10.
  11. 11.
    L. Asinovsky, M. Schroth, F. Shen, J.J. Sweeney, Characterization and metrology of the diffusion doped polysilicon using Ellipsometry. Thin Solid Films 313314, 248–253 (1998)CrossRefGoogle Scholar
  12. 12.
    H. Günther, Optical Properties of Polycrystalline Silicon Films, vol. 57 (Springer Series in Solid-State Sciences, New York, 1985), pp. 156–169Google Scholar
  13. 13.
    P. Petrik, L.P. Biro, M. Fried, T. Lohner, R. Berger, C. Schneider, J. Gyulai, H. Ryssel, Comparative study of surface roughness measured on polysilicon using spectroscopic ellipsometry and atomic force microscopy. Thin Solid Films 315, 186–191 (1998)CrossRefGoogle Scholar
  14. 14.
    B. Gruska, Ellipsometric analysis of polysilicon layers. Thin Solid Films 364, 138–143 (2000)CrossRefGoogle Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Renewable Energies Laboratory (LER)Jijel UniversityJijelAlgeria
  2. 2.ICTEAMUniversité catholique de Louvain (UCL)Louvain-la-NeuveBelgium

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