Title :
Ozone Sensors based on Layered SAW Devices with: InOx/SiNx/36° YX LiTaO3 Structure
Author :
Fechete, Alexandru C. ; Wlodarski, Wojtek B. ; Kalantar-zadeh, Kourosh ; Holland, Anthony S. ; Wisistsora-at, Anurat
Author_Institution :
Dept. of Electr. & Comput. Eng., RMIT Univ., Melbourne, VIC
Abstract :
Monitoring of air-quality it is a major task nowadays as the emission of pollutant gases increases particularly in urban areas. Ozone (O3) is a significant toxic pollutant and presents health risks. We have developed ozone sensors using a surface acoustic wave (SAW) based devices. The sensors structure consists of a lithium tantalate piezoelectric (LiTaO3) substrate with silicon nitride (SiNx) intermediate layer deposited by R.F. magnetron sputtering and e-beam evaporation techniques. A 100 nm thin film of indium oxide (InOx) deposited by R.F. magnetron sputtering provides the selectivity towards O3. This paper presents a comparative study of the sensors performance in terms of response time, recovery time and response magnitude as a function of operational temperature. Exceptionally large frequency shift as high as 56 kHz was observed for O3 concentrations as low as 50 parts per billion (ppb) in air. Microstructural characterization of the InOx thin films by atomic force microscopy (AFM) is also presented.
Keywords :
air pollution measurement; atomic force microscopy; electron beam deposition; gas sensors; indium compounds; lithium compounds; ozone; piezoelectric materials; silicon compounds; sputtered coatings; surface acoustic wave sensors; thin film sensors; AFM; InOx-SiNx-LiTaO3; RF magnetron sputtering; air-quality monitoring; atomic force microscopy; e-beam evaporation techniques; frequency shift; health risk; indium oxide thin film; layered SAW devices; lithium tantalate piezoelectric substrate; microstructural characterization; ozone sensors; pollutant gas emission; silicon nitride intermediate layer; size 100 nm; surface acoustic wave based devices; toxic pollutant; Acoustic sensors; Atomic force microscopy; Gases; Magnetic sensors; Monitoring; Sputtering; Surface acoustic wave devices; Temperature sensors; Urban areas; Urban pollution; Indium oxide; Ozone; SAW sensors; Silicon nitride;
Conference_Titel :
TENCON 2005 2005 IEEE Region 10
Conference_Location :
Melbourne, Qld.
Print_ISBN :
0-7803-9311-2
Electronic_ISBN :
0-7803-9312-0
DOI :
10.1109/TENCON.2005.301325
