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Proceedings Paper

Integration of SnO2 sol-gel processes to gas sensor microfabrication: H2 and CO sensitivity evaluation
Author(s): Corbel Cobianu; Raluca Iorgulescu; Cristian Savaniu; Antonela Dima; Dan C. Dascalu; Pietro Siciliano; Simona Capone; Roberto Rella; Fabio Quaranta; Lorenzo Vasanelli
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Paper Abstract

Sol-gel organic synthesis of SnO2 thin films from tin ethoxide precursor is reported here as a promising and cheap alternative of the 'classical' chemical and physical preparation methods of the SnO2 thin films, for gas sensing applications. A simple, integrated circuit compatible test structure, for rapid evaluation of the sensing properties of the SnO2 sol-gel derived thin films is described. The main features of our microstructure consists of a a heating resistor integrated on chip, made of highly boron doped silicon and a metallization system from Au/W deposited on a planarized chemically vapor deposited SiO2 layer. The SnO2 films have shown the well-known increase-maximum-decrease dependence of chemoresistance as a function of temperature, with a maximum at about 380 degrees C, when they are measured in clean, dry air. The sensitivity of SnO2 films to high concentration of H2 in air was studied within a quartz furnace, externally heated in the temperature range from 200 to 450 degrees C. The relative sensitivity is equal to 100 percent at temperatures as low as 200 degrees C, while its maximum value is anticipated to be above 450 degrees C. The CO sensing properties of SnO2 layers were evaluated as a function of input power applied on the integrated heating resistor. We have obtained relative sensitivities of 30 percent for 500 ppm CO concentration in dry air and an input power of 209 mW.

Paper Details

Date Published: 10 March 1999
PDF: 8 pages
Proc. SPIE 3680, Design, Test, and Microfabrication of MEMS and MOEMS, (10 March 1999); doi: 10.1117/12.341188
Show Author Affiliations
Corbel Cobianu, National Institute for Research and Development in Microtechnologies (Romania)
Raluca Iorgulescu, National Institute for Research and Development in Microtechnologies (Romania)
Cristian Savaniu, National Institute for Research and Development in Microtechnologies (Romania)
Antonela Dima, National Institute for Research and Development in Microtechnologies (Romania)
Dan C. Dascalu, National Institute for Research and Development in Microtechnologies (Romania)
Pietro Siciliano, IME/CNR (Italy)
Simona Capone, IME/CNR (Italy)
Roberto Rella, IME/CNR (Italy)
Fabio Quaranta, IME/CNR (Italy)
Lorenzo Vasanelli, IME/CNR (Italy)


Published in SPIE Proceedings Vol. 3680:
Design, Test, and Microfabrication of MEMS and MOEMS
Bernard Courtois; Wolfgang Ehrfeld; Selden B. Crary; Wolfgang Ehrfeld; Hiroyuki Fujita; Jean Michel Karam; Karen W. Markus, Editor(s)

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