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Measurement of thin film interfacial surface roughness by coherence scanning interferometry

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journal contribution
posted on 31.03.2017, 13:20 by Hiro Yoshino, Ali AbbasAli Abbas, Piotr M. Kaminski, Roger SmithRoger Smith, Michael WallsMichael Walls, D. Mansfield
Coherence Scanning Interferometry (CSI), which is also referred to as scanning white light interferometry, is a well-established optical method used to measure the surface roughness and topography with sub-nanometer precision. One of the challenges CSI has faced is extracting the interfacial topographies of a thin film assembly, where the thin film layers are deposited on a substrate, and each interface has its own defined roughness. What makes this analysis difficult is that the peaks of the interference signal are too close to each other to be separately identified. The Helical Complex Field (HCF) function is a topographically defined helix modulated by the electrical field reflectance, originally conceived for the measurement of thin film thickness. In this paper, we verify a new technique, which uses a first order Taylor expansion of the HCF function to determine the interfacial topographies at each pixel, so avoiding a heavy computation. The method is demonstrated on the surfaces of Silicon wafers using deposited Silica and Zirconia oxide thin films as test examples. These measurements show a reasonable agreement with those obtained by conventional CSI measurement of the bare Silicon wafer substrates.

Funding

The authors are grateful to RCUK for financial support through the SuperSolar Hub (EPSCR Grant No. EP/J017361/1).

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Journal of Applied Physics

Volume

121

Issue

10

Citation

YOSHINO, H. ... et al., 2017. Measurement of thin film interfacial surface roughness by coherence scanning interferometry. Journal of Applied Physics, 121, 105303; doi: 10.1063/1.4978066

Publisher

AIP Publishing LLC © Author(s)

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Acceptance date

01/03/2017

Publication date

2017-03-10

Copyright date

2017

Notes

All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

ISSN

0021-8979

eISSN

1089-7550

Language

en