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


Pissadakis, S., Ikiades, A., Tai, C.Y., Sessions, N.P. and Wilkinson, J.S. (2003) Sub-micron period grating structures in Ta thin oxide films patterned using UV laser post-exposure chemically assisted selective etching. In, E-MRS 2003 Spring Meeting, Strasbourg, France, 10 - 13 Jun 2003. Strasbourg, France, European Materials Research Society1pp.

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Description/Abstract

Thin polycrystalline films of Ta 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/cm 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.

Item Type: Conference or Workshop Item (Lecture)
Additional Information: Symposium title: Photonic Processing of Surfaces, Thin Films and Devices
Related URLs:
Subjects: T Technology > TP Chemical technology
T Technology > TK Electrical engineering. Electronics Nuclear engineering
Q Science > QC Physics
Divisions: University Structure - Pre August 2011 > Optoelectronics Research Centre
ePrint ID: 41616
Date Deposited: 06 Oct 2006
Last Modified: 27 Mar 2014 18:26
Publisher: European Materials Research Society
URI: http://eprints.soton.ac.uk/id/eprint/41616

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