Publication detail

Simultaneous determination of optical constants, local thickness and roughness of ZnSe thin films by imaging spectroscopic reflectometry

NEČAS, D. OHLÍDAL, I. FRANTA, D. OHLÍDAL, M. VODÁK, J.

Original Title

Simultaneous determination of optical constants, local thickness and roughness of ZnSe thin films by imaging spectroscopic reflectometry

Type

journal article in Web of Science

Language

English

Original Abstract

A rough non-uniform ZnSe thin film on a GaAs substrate is optically characterised using imaging spectroscopic reflectometry (ISR) in the visible, UV and near IR region, applied as a standalone technique. A global-local data processing algorithm is used to fit spectra from all pixels together and simultaneously determine maps of the local film thickness, roughness and overlayer thickness as well as spectral dependencies of film optical constants determined for the sample as a whole. The roughness of the film upper boundary is modelled using scalar diffraction theory (SDT), for which an improved calculation method is developed to process the large quantities of experimental data produced by ISR efficiently. This method avoids expensive operations by expressing the series obtained from SDT using a double recurrence relation and it is shown that it essentially eliminates the necessity for any speed-precision trade-offs in the SDT calculations. Comparison of characterisation results with the literature and other techniques shows the ability of multi-pixel processing to improve the stability and reliability of least-squares data fitting and demonstrates that standalone ISR, coupled with suitable data processing methods, is viable as a characterisation technique, even for thin films that are relatively far from ideal and require complex modelling.

Keywords

thin films; roughness; scalar diffraction theory; spectrophotometry; imaging techniques; zinc selenide; reflectometry

Authors

NEČAS, D.; OHLÍDAL, I.; FRANTA, D.; OHLÍDAL, M.; VODÁK, J.

Released

18. 1. 2016

Publisher

IOP PUBLISHING LTD

Location

TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND

ISBN

2040-8978

Periodical

JOURNAL OF OPTICS

Year of study

18

Number

1

State

United Kingdom of Great Britain and Northern Ireland

Pages from

2

Pages to

11

Pages count

10

URL

http://iopscience.iop.org/article/10.1088/2040-8978/18/1/015401/pdf

BibTex

@article{BUT123838,
  author="David {Nečas} and Ivan {Ohlídal} and Daniel {Franta} and Miloslav {Ohlídal} and Jiří {Vodák}",
  title="Simultaneous determination of optical constants, local thickness and roughness of ZnSe thin films by imaging spectroscopic reflectometry",
  journal="JOURNAL OF OPTICS",
  year="2016",
  volume="18",
  number="1",
  pages="2--11",
  doi="10.1088/2040-8978/18/1/015401",
  issn="2040-8978",
  url="http://iopscience.iop.org/article/10.1088/2040-8978/18/1/015401/pdf"
}