Micromirror Angle Dependence with Etchant Choice on <100> Silicon Via Wet Etching

Al-Hafidh, M., Wilson, R. , Glidle, A., Reboud, J. , Kelly, A. and Cooper, J.M. (2019) Micromirror Angle Dependence with Etchant Choice on <100> Silicon Via Wet Etching. In: 2018 IEEE 18th International Conference on Nanotechnology (IEEE-NANO), Cork, Ireland, 23-26 Jul 2018, ISBN 9781538653364 (doi:10.1109/NANO.2018.8626355)

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Abstract

In creating mirrored silicon structures for micro-optics, the smoothness of the surface and etch rate are crucial parameters. We demonstrate a method of creating both 45° and 90° etch-planes from monocrystalline silicon for use as retro-reflective sidewalls in a microfluidic device. The technique uses the same photolithographic pattern orientation, but with two different etchants. Etching on <;100> direction in Si(100) with potassium hydroxide (KOH) gives vertical surfaces (where e.g. the high surface tension influences etching of crystallographic silicon planes), whilst tetramethylammonium hydroxide (TMAH) gives 45° sidewalls. We illustrate the use of these fabricated structures by creating arrays of micromirrors that enable an optical beam to be reflected parallel back and forth from 45° and -45° tilted vertical structures. This device has potential uses in optofluidic spectroscopic applications, where there is a need to increase the effective pathlength of a beam through a sample whilst keeping the device as small as possible.

Item Type:Conference Proceedings
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Wilson, Dr Robert and Glidle, Dr Andrew and Al-Hafidh, Ms Maab and Cooper, Professor Jonathan and Reboud, Dr Julien and Kelly, Professor Anthony
Authors: Al-Hafidh, M., Wilson, R., Glidle, A., Reboud, J., Kelly, A., and Cooper, J.M.
College/School:College of Science and Engineering > School of Engineering > Biomedical Engineering
College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
ISSN:1944-9380
ISBN:9781538653364
Published Online:28 January 2019
Copyright Holders:Copyright © 2018 IEEE
First Published:First published in 2018 IEEE 18th International Conference on Nanotechnology (IEEE-NANO)
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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