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Proceedings Paper

Synthesis of Si nanowires for MEMS cantilever sensor applications
Author(s): S. M. Prokes; Stephen Arnold
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Paper Abstract

We present a new approach for growing Si nanowires directly from a silicon substrate, without the use of a metal catalyst, silicon vapor or CVD gasses. The growth can be performed in a furnace type configuration at moderate temperatures or in localized regions by resistive heating. Since the silicon wires grow directly from the silicon substrate, they do not need to be manipulated nor aligned for subsequent applications. Wires in the 20-50 nm diameter range with lengths over 80 μm can be grown by this technique. We have studied the effects of various growth parameters, including temperature, substrate orientation, initial sample cleaning and carrier gasses. Results indicate that most important parameters in the growth of the nanowires are the surface cleaning, the temperature and the type of carrier gas used. A model is proposed, which involves an oxide catalyst for the process, with the growth of the nanowires enabled by a significantly enhanced silicon surface diffusion process, due to adsorption of hydrogen gas on the substrate surface. These nanowires can be grown locally by resistive heating, and thus they are ideal candidates for direct growth on a MEMS cantilever sensor, where the Si nanowire growth can be performed in such a way that the rest of the structure remains at low temperature, reducing the chance of high temperature damage of already processed regions. The wires, once formed on the MEMS device, can be used as adsorption sites for an NRL sorptive polymer, which is currently being used for nerve gas detection. The addition of the nanowires enhances the surface area significantly and thereby it is expected to improve the detection capability of the MEMS structure.

Paper Details

Date Published: 29 December 2004
PDF: 13 pages
Proc. SPIE 5593, Nanosensing: Materials and Devices, (29 December 2004); doi: 10.1117/12.578765
Show Author Affiliations
S. M. Prokes, Naval Research Lab. (United States)
Stephen Arnold, Naval Research Lab. (United States)

Published in SPIE Proceedings Vol. 5593:
Nanosensing: Materials and Devices
M. Saif Islam; Achyut K. Dutta, Editor(s)

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