
Proceedings Paper
A comparison of wet and dry etching to fabricate a micro-photonic structure for use in OCTFormat | Member Price | Non-Member Price |
---|---|---|
$17.00 | $21.00 |
Paper Abstract
In conventional time-domain Optical Coherence Tomography (OCT), a moving mirror is used as a reference optical
delay line. This motion can result in instrument degradation, and in some situations it is preferable to have no moving
parts. Stationary optical delay lines using a variety of methods have been proposed. Of particular interest, due to its low
cost, is the use of a micro-photonic stationary optical delay line, made up of an addressable Stepped Mirror Structure
(SMS) using a liquid crystal optical switch. Here the individual steps of the SMS can be selected by the liquid crystal
array. For use in OCT, the discrete nature of the SMS needs to be overcome by having the step height less than the
coherence length of the low coherent light source. Typical coherence lengths in current OCT systems are on the order of
10μm. Hence, micrometer size steps require the use of a relevant fabrication method. In this paper, we compare SMSs
fabricated using wet and dry etching methods. Specifically, Reactive Ion Etching (RIE) using CF4/O2 and chemical bath
etching, using a solution of HF, HNO3 and Acetic acid. Three inch diameter silicon wafers, 400μm thick, were etched by
both methods. The RIE was used to produce a SMS with five 5μm high steps each step approximately 1 cm wide. The
wet etching produced an SMS with three 15μm steps approximately 2 cm wide. The overall structures of the SMSs were
compared using optical profilometry. The RIE step quality was far superior to the wet etch method due to the ability to
control the anisotropy of the RIE method.
Paper Details
Date Published: 30 December 2008
PDF: 11 pages
Proc. SPIE 7270, Biomedical Applications of Micro- and Nanoengineering IV and Complex Systems, 727016 (30 December 2008); doi: 10.1117/12.810973
Published in SPIE Proceedings Vol. 7270:
Biomedical Applications of Micro- and Nanoengineering IV and Complex Systems
Dan V. Nicolau; Guy Metcalfe, Editor(s)
PDF: 11 pages
Proc. SPIE 7270, Biomedical Applications of Micro- and Nanoengineering IV and Complex Systems, 727016 (30 December 2008); doi: 10.1117/12.810973
Show Author Affiliations
Steven Hinckley, Edith Cowan Univ. (Australia)
Published in SPIE Proceedings Vol. 7270:
Biomedical Applications of Micro- and Nanoengineering IV and Complex Systems
Dan V. Nicolau; Guy Metcalfe, Editor(s)
© SPIE. Terms of Use
