Detail publikace

Simultaneous determination of dispersion model parameters and local thickness of thin films by imaging spectrophotometry

NEČAS, D. VODÁK, J. OHLÍDAL, I. OHLÍDAL, M. MAJUMDAR, A. ZAJÍČKOVÁ, L.

Originální název

Simultaneous determination of dispersion model parameters and local thickness of thin films by imaging spectrophotometry

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

angličtina

Originální abstrakt

A least-squares data fitting procedure is developed for the analysis of measurements of thin films non-uniform in thickness by imaging spectroscopic reflectometry. It solves the problem of simultaneous least-squares fitting of film thicknesses in all image pixels together with shared dispersion model parameters. Since the huge number of mutually correlated fitting parameters prevents a straightforward application of the standard Levenberg–Marquardt algorithm, the presented procedure exploits the special structure of the specific least-squares problem. The free parameters are split into thicknesses and dispersion model parameters. Both groups of parameters are fitted alternately, utilising an unmodified Levenberg–Marquardt algorithm, correcting however the thicknesses during the dispersion model fitting step to preserve effective optical thicknesses. The behaviour of the algorithm is studied using experimental data of two highly non-uniform thin films of different materials, SiOxCyHz and CNx:H, and by numerical simulations using artificial data. It is found that the optical thickness correction enables the procedure to converge rapidly, permitting the analysis of large imaging spectroscopic reflectometry data sets with reasonable computational resources.

Klíčová slova

Imaging spectrophotometry; Thin films; Optical properties; Thickness mapping; Non-linear least-squares; Levenberg–Marquardt

Autoři

NEČAS, D.; VODÁK, J.; OHLÍDAL, I.; OHLÍDAL, M.; MAJUMDAR, A.; ZAJÍČKOVÁ, L.

Rok RIV

2015

Vydáno

23. 1. 2015

Nakladatel

Applied Surface Science

ISSN

0169-4332

Periodikum

Applied Surface Science

Číslo

350

Stát

Nizozemsko

Strany od

149

Strany do

155

Strany počet

7

URL

http://www.sciencedirect.com/science/article/pii/S016943321500118X

BibTex

@article{BUT115038,
  author="David {Nečas} and Jiří {Vodák} and Ivan {Ohlídal} and Miloslav {Ohlídal} and Abhijit {Majumdar} and Lenka {Zajíčková}",
  title="Simultaneous determination of dispersion model parameters and local thickness of thin films by imaging spectrophotometry",
  journal="Applied Surface Science",
  year="2015",
  number="350",
  pages="149--155",
  doi="10.1016/j.apsusc.2015.01.093",
  issn="0169-4332",
  url="http://www.sciencedirect.com/science/article/pii/S016943321500118X"
}