The University of Southampton
University of Southampton Institutional Repository

Electron beam lithography for high density meta fish scale operational at optical frequency

Electron beam lithography for high density meta fish scale operational at optical frequency
Electron beam lithography for high density meta fish scale operational at optical frequency
Planar metamaterials possesses novel physical property beyond the physics limit in bulk materials. One of the meta structures is fish scale (both chiral and non chiral), which has been discovered to behave like a magnetic mirror [1] in micrometer/millimetre wavelength. To investigate the unusual interaction between the electromagnetic wave and the meta fish scale pattern in optical wavelength, high resolution and high density electron beam lithography is demanded. As shown in figure 1, the planar photonic device in question is a wavy-line structure with the pitch of 500 nm and linewidth of 50 nm of Al. When such a metamaterial is structured on silicon coated with a 100 nm thick Al, the device is in the reflection mode, whilst directly on quartz substrate, it is in the transmission mode. The key challenge in this nanofabrication technique is to lift off unwanted Al metals with the density of 50 nm lines/spaces. To fabricate such dense pattern, four different bilayers of resists have been tested and compared. They are PMMA/PMMA-MAA, PMMA/LOR, PMMA(MW350k)/PMMA(100k), PMMA/ZEP. The electron beam lithography system used in this work is a VB6 HR supplied by Vistech Ltd. An e-beam with 100 keV acceleration energy, 12 nm spot size and 500 pA was applied for the exposure of the resist. To avoid the charging effect when using e-beam to write fish scale pattern on insulating quartz wafers, a thin Al layer was coated on the top of the resist by thermal evaporation. Comparison of the contrast curves of the four resists were measured, which are a guide for the combination of the resists in the bilayer technique. It was found that although PMMA/LOR bilayer produces the best undercut (not presented), it is not suitable for the device because the remover of LOR also attacks Al film. PMMA/PMMA-MAA also demonstrated a good undercut profile required by lift-off, but its undercut is too large such that it is not suitable for dense pattern with 50 nm gap. The same situation happens to PMMA/ZEP bilayer because both ZEP resist and PMMA-MAA has very similar sensitivity. PMMA(MW350K)/PMMA(MW100k) bilayer has smaller undercut because the sensitivity of each layer is very close, which is found to suit the dense structure the most. Therefore, a PMMA/PMMA with different molecular weights was finally selected for the process for the dense fish scale pattern. Figure 2 presents the fish scale patterns in both resist and metallised structures. A number of novel physics from the fabricated meta fish scale have been discovered including magnetic mirror (figure3) [2], resonant absorption of light and asymmetric propagation of electromagnetic waves [3].By summary, high resolution electron beam lithography has been applied for the fabrication of planar meta materials and nanophotonic materials. This technique is promising for generating photonic nanostructures in optical frequency for broader applications in bioscience and microwave communications.
Chen, Yifang
fb868aa4-ecb4-4203-a0a8-88c2195a2bae
Schwanecke, Alexander S.
2f6c06ac-00e6-4e9f-ae02-ba851d99e7f5
Fedotov, V.A.
3725f5cc-2d0b-4e61-95c5-26d187c84f25
Khardikov, V.V.
01d600d3-32d0-495f-a4bb-8e966e5f6ec4
Mladyonov, P.L.
eb060f33-20dc-4a62-9698-1ea0b9e9f548
Prosvirnin, S.L.
a12695af-60fb-46bd-a711-032547ce8167
Rogacheva, A.V.
07e3c6ce-4e4d-4660-87fd-b04e7061b3ee
Zheludev, Nikolay
32fb6af7-97e4-4d11-bca6-805745e40cc6
Huq, Ejaz
6ba52b03-395d-4361-96b0-5f0d9d7eb746
Chen, Yifang
fb868aa4-ecb4-4203-a0a8-88c2195a2bae
Schwanecke, Alexander S.
2f6c06ac-00e6-4e9f-ae02-ba851d99e7f5
Fedotov, V.A.
3725f5cc-2d0b-4e61-95c5-26d187c84f25
Khardikov, V.V.
01d600d3-32d0-495f-a4bb-8e966e5f6ec4
Mladyonov, P.L.
eb060f33-20dc-4a62-9698-1ea0b9e9f548
Prosvirnin, S.L.
a12695af-60fb-46bd-a711-032547ce8167
Rogacheva, A.V.
07e3c6ce-4e4d-4660-87fd-b04e7061b3ee
Zheludev, Nikolay
32fb6af7-97e4-4d11-bca6-805745e40cc6
Huq, Ejaz
6ba52b03-395d-4361-96b0-5f0d9d7eb746

Chen, Yifang, Schwanecke, Alexander S., Fedotov, V.A., Khardikov, V.V., Mladyonov, P.L., Prosvirnin, S.L., Rogacheva, A.V., Zheludev, Nikolay and Huq, Ejaz (2008) Electron beam lithography for high density meta fish scale operational at optical frequency. 34th International Conference on Micro & Nano Engineering, , Athens, Greece. 15 - 19 Sep 2008.

Record type: Conference or Workshop Item (Paper)

Abstract

Planar metamaterials possesses novel physical property beyond the physics limit in bulk materials. One of the meta structures is fish scale (both chiral and non chiral), which has been discovered to behave like a magnetic mirror [1] in micrometer/millimetre wavelength. To investigate the unusual interaction between the electromagnetic wave and the meta fish scale pattern in optical wavelength, high resolution and high density electron beam lithography is demanded. As shown in figure 1, the planar photonic device in question is a wavy-line structure with the pitch of 500 nm and linewidth of 50 nm of Al. When such a metamaterial is structured on silicon coated with a 100 nm thick Al, the device is in the reflection mode, whilst directly on quartz substrate, it is in the transmission mode. The key challenge in this nanofabrication technique is to lift off unwanted Al metals with the density of 50 nm lines/spaces. To fabricate such dense pattern, four different bilayers of resists have been tested and compared. They are PMMA/PMMA-MAA, PMMA/LOR, PMMA(MW350k)/PMMA(100k), PMMA/ZEP. The electron beam lithography system used in this work is a VB6 HR supplied by Vistech Ltd. An e-beam with 100 keV acceleration energy, 12 nm spot size and 500 pA was applied for the exposure of the resist. To avoid the charging effect when using e-beam to write fish scale pattern on insulating quartz wafers, a thin Al layer was coated on the top of the resist by thermal evaporation. Comparison of the contrast curves of the four resists were measured, which are a guide for the combination of the resists in the bilayer technique. It was found that although PMMA/LOR bilayer produces the best undercut (not presented), it is not suitable for the device because the remover of LOR also attacks Al film. PMMA/PMMA-MAA also demonstrated a good undercut profile required by lift-off, but its undercut is too large such that it is not suitable for dense pattern with 50 nm gap. The same situation happens to PMMA/ZEP bilayer because both ZEP resist and PMMA-MAA has very similar sensitivity. PMMA(MW350K)/PMMA(MW100k) bilayer has smaller undercut because the sensitivity of each layer is very close, which is found to suit the dense structure the most. Therefore, a PMMA/PMMA with different molecular weights was finally selected for the process for the dense fish scale pattern. Figure 2 presents the fish scale patterns in both resist and metallised structures. A number of novel physics from the fabricated meta fish scale have been discovered including magnetic mirror (figure3) [2], resonant absorption of light and asymmetric propagation of electromagnetic waves [3].By summary, high resolution electron beam lithography has been applied for the fabrication of planar meta materials and nanophotonic materials. This technique is promising for generating photonic nanostructures in optical frequency for broader applications in bioscience and microwave communications.

Text
4217.pdf - Author's Original
Restricted to Repository staff only
Request a copy

More information

Published date: September 2008
Venue - Dates: 34th International Conference on Micro & Nano Engineering, , Athens, Greece, 2008-09-15 - 2008-09-19

Identifiers

Local EPrints ID: 65466
URI: http://eprints.soton.ac.uk/id/eprint/65466
PURE UUID: 2b92969f-1aef-4028-af0f-d69408762550
ORCID for Nikolay Zheludev: ORCID iD orcid.org/0000-0002-1013-6636

Catalogue record

Date deposited: 19 Feb 2009
Last modified: 14 Mar 2024 02:36

Export record

Contributors

Author: Yifang Chen
Author: Alexander S. Schwanecke
Author: V.A. Fedotov
Author: V.V. Khardikov
Author: P.L. Mladyonov
Author: S.L. Prosvirnin
Author: A.V. Rogacheva
Author: Nikolay Zheludev ORCID iD
Author: Ejaz Huq

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×