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An ammonia sensor based on porous SiC

Eamon J. Connolly 1Bjorn Timmer 2Mai Hoa T. Pham 1Jan Groneweg 1Lina Sarro 1Wouter Olthuis 2Paddy French 1

1. University of Technology Delft, Rotterdamseweg 137, Delft 2628 AL, Netherlands
2. University of Twente, Faculty of Science and Technology, Low Temperature Division and MESA+ Research Institute, Postbus 217, Enschede 7500 AE, Netherlands

Abstract

Porous SiC has been found to be extremely sensitive to the presence of ammonia (NH3) gas. We report the fabrication and preliminary characterisation of NH3 sensors based on porous SiC and Al electrodes. The idea of the SiC is that it is a very durable material and that it should be good for sensors in harsh environments. Until now the only NH3 sensors using SiC have been FET based, and the SiC was not porous. The SiC was deposited by PECVD on standard p-type single-crystal Si and was made porous by electrochemical etching in 73% HF and anodisation current-densities of 1-50mA/cm2. Because the etch-rate of Al in 73% HF is very low, we can use Al electrodes instead of Au. This also facilitates our sensor fabrication, as Al is more cleanroom friendly than Au. Preliminary data is given for our devices response to NH3 in the range 0-10ppm NH3 in dry N2 carrier gas.

 

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Presentation: oral at E-MRS Fall Meeting 2004, Symposium A, by Eamon J. Connolly
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-23 15:14
Revised:   2009-06-08 12:55