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Sub-micron period grating structures in Ta2O5 thin oxide films patterned using UV laser post-exposure chemically assisted selective etching

Sub-micron period grating structures in Ta2O5 thin oxide films patterned using UV laser post-exposure chemically assisted selective etching
Sub-micron period grating structures in Ta2O5 thin oxide films patterned using UV laser post-exposure chemically assisted selective etching
Thin polycrystalline films of Ta2O5 having high chemical resistance and large dielectric permittivity may be deposited by sputtering and have many applications in microelectronics and optoelectronics. A high-resolution and low-damage method for patterning relief structures in thin Ta2O5 films by chemically assisted UV laser selective etching is presented. The method is based in the initial exposure of the Ta2O5 films to pulsed UV radiation (quadrupled Nd:YAG laser at 266nm) at fluences below the ablation threshold, for the creation of volume damage in the exposed areas. Subsequent immersion of the exposed sample in a KOH solution results in selective etching of the UV-exposed areas, developing relief structures of high quality. Interferometric exposure was used for the patterning of such gratings with periods shorter than 500nm in films of thickness between 100nm and 500nm. The behaviour of the patterning process is studied using diffraction efficiency measurements, AFM and SEM scans. Diffraction efficiency increases by a factor of 66, compared to the undeveloped structure, were obtained for gratings exposed with 1000 pulses of 30mJ/cm2 energy density, which were developed in a KOH solution of 50% weight concentration at a temperature of 55°C for 165mins. The etching method presented is being applied to the fabrication of optical waveguide gratings for telecommunication applications. Potential development of 2-D photonic crystal structures using this process is under investigation.
Pissadakis, S.
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Ikiades, A.
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Tai, C.Y.
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Sessions, N.P.
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Wilkinson, J.S.
73483cf3-d9f2-4688-9b09-1c84257884ca
Pissadakis, S.
a91c54e0-3b8d-479f-b44e-e678bc34a277
Ikiades, A.
6b4f12e0-7ded-43fb-8a61-e2b725f65cb3
Tai, C.Y.
5ce36f32-5d16-4c47-971f-ce5b86092061
Sessions, N.P.
ee737092-56b4-403e-a2f9-764e07e42625
Wilkinson, J.S.
73483cf3-d9f2-4688-9b09-1c84257884ca

Pissadakis, S., Ikiades, A., Tai, C.Y., Sessions, N.P. and Wilkinson, J.S. (2003) Sub-micron period grating structures in Ta2O5 thin oxide films patterned using UV laser post-exposure chemically assisted selective etching. E-MRS 2003 Spring Meeting, France. 09 - 12 Jun 2003. 1 pp .

Record type: Conference or Workshop Item (Other)

Abstract

Thin polycrystalline films of Ta2O5 having high chemical resistance and large dielectric permittivity may be deposited by sputtering and have many applications in microelectronics and optoelectronics. A high-resolution and low-damage method for patterning relief structures in thin Ta2O5 films by chemically assisted UV laser selective etching is presented. The method is based in the initial exposure of the Ta2O5 films to pulsed UV radiation (quadrupled Nd:YAG laser at 266nm) at fluences below the ablation threshold, for the creation of volume damage in the exposed areas. Subsequent immersion of the exposed sample in a KOH solution results in selective etching of the UV-exposed areas, developing relief structures of high quality. Interferometric exposure was used for the patterning of such gratings with periods shorter than 500nm in films of thickness between 100nm and 500nm. The behaviour of the patterning process is studied using diffraction efficiency measurements, AFM and SEM scans. Diffraction efficiency increases by a factor of 66, compared to the undeveloped structure, were obtained for gratings exposed with 1000 pulses of 30mJ/cm2 energy density, which were developed in a KOH solution of 50% weight concentration at a temperature of 55°C for 165mins. The etching method presented is being applied to the fabrication of optical waveguide gratings for telecommunication applications. Potential development of 2-D photonic crystal structures using this process is under investigation.

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More information

e-pub ahead of print date: 2003
Additional Information: Symposium title: Photonic Processing of Surfaces, Thin Films and Devices
Venue - Dates: E-MRS 2003 Spring Meeting, France, 2003-06-09 - 2003-06-12

Identifiers

Local EPrints ID: 41616
URI: http://eprints.soton.ac.uk/id/eprint/41616
PURE UUID: ba7e0393-36a2-497e-ad17-8e0634835143
ORCID for J.S. Wilkinson: ORCID iD orcid.org/0000-0003-4712-1697

Catalogue record

Date deposited: 06 Oct 2006
Last modified: 18 Feb 2021 16:32

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