Controlling the optical properties of hafnium dioxide thin films deposited with electron cyclotron resonance ion beam deposition

Gier, C. et al. (2023) Controlling the optical properties of hafnium dioxide thin films deposited with electron cyclotron resonance ion beam deposition. Thin Solid Films, 771, 139781. (doi: 10.1016/j.tsf.2023.139781)

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Abstract

The effects of reactive and sputtering oxygen partial pressure on the structure, stoichiometry and optical properties of hafnium oxide (HfO2) thin films have been systematically investigated. The electron cyclotron resonance ion beam deposition (ECR-IBD) technique was used to fabricate the films on to JGS-3 fused silica substrates. The amorphous structure of HfO2 films were determined by X-ray Diffraction. Energy-dispersive X-ray Spectroscopy and Rutherford Backscattering Spectrometry were carried out for the composition and stoichiometry analysis, where this suggests the formation of over-stoichiometric films. The data suggests that the O:Hf ratio ranges from 2.4 – 4.45 to 1 for the ECR-IBD fabricated HfO2 films in this study. The transmission and reflectance spectra of the HfO2 films were measured over a wide range of wavelengths (λ = 185 – 3000 nm) by utilizing a spectrophotometer. The measured spectra were analyzed by an optical fitting software, which utilizes the model modified by O'Leary, Johnson and Lim, to extract the optical properties, refractive index (n) and the bandgap energy (E0). By varying the reactive and sputtering oxygen partial pressure, the optical properties were found to be n = 1.70 – 1.91, and E0 = 5.6 – 6.0 eV. This study provides a flexible method for tuning the optical properties of HfO2 coatings by controlling the mixture of reactive and sputtering gas.

Item Type:Articles
Additional Information:This work was supported by the Science and Technology Facilities Council [grant numbers ST/S001832/1, ST/T003367/1], the University of Strathclyde, the University of Glasgow, and Gooch and House Ltd.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Rowan, Professor Sheila and Martin, Dr Iain and Hough, Professor James
Creator Roles:
Hough, J.Funding acquisition
Rowan, S.Funding acquisition
Martin, I.Funding acquisition
Authors: Gier, C., Yaala, M. B., Wiseman, C., MacFoy, S., Chicoine, M., Schiettekatte, F., Hough, J., Rowan, S., Martin, I., MacKay, P., and Reid, S.
College/School:College of Science and Engineering > School of Physics and Astronomy
Research Centre:College of Science and Engineering > School of Physics and Astronomy > Institute for Gravitational Research
Journal Name:Thin Solid Films
Publisher:Elsevier
ISSN:0040-6090
ISSN (Online):1879-2731
Published Online:05 March 2023
Copyright Holders:Copyright © 2023 The Authors
First Published:First published in Thin Solid Films 771: 139781
Publisher Policy:Reproduced under a Creative Commons License

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