Temperature Frequency Characteristics of Hexamethyldisiloxane (HMDSO) Polymer Coated Rayleigh Surface Acoustic Wave (SAW) Resonators for Gas-Phase Sensor Applications
Temperature induced frequency shifts may compromise the sensor response of polymer coated acoustic wave gas-phase sensors operating in environments of variable temperature. To correct the sensor data with the temperature response of the sensor the latter must be known. This study presents and discusses temperature frequency characteristics (TFCs) of solid hexamethyldisiloxane (HMDSO) polymer coated sensor resonators using the Rayleigh surface acoustic wave (RSAW) mode on ST-cut quartz. Using a RF-plasma polymerization process, RSAW sensor resonators optimized for maximum gas sensitivity have been coated with chemosensitive HMDSO films at 4 different thicknesses: 50, 100, 150 and 250 nm. Their TFCs have been measured over a (？100 to +110) °C temperature range and compared to the TFC of an uncoated device. An exponential 2,500 ppm downshift of the resonant frequency and a 40 K downshift of the sensor’s turn-over temperature (TOT) are observed when the HMDSO thickness increases from 0 to 250 nm. A partial temperature compensation effect caused by the film is also observed. A third order polynomial fit provides excellent agreement with the experimental TFC curve. The frequency downshift due to mass loading by the film, the TOT and the temperature coefficients are unambiguously related to each other.
References
[1]
White, R.M. Surface acoustic wave sensors. In Proceedings of IEEE 1985 Ultrasonics Symposium, San Francisco, CA, USA, 16–18 October 1985; pp. 490–494.
[2]
White, R.M. Acoustic sensors for physical, chemical and biochemical applications. In Proceedings of IEEE 1998 International Frequency Control Symposium, Pasadena, CA, USA, 27–29 May 1998; pp. 587–594.
[3]
Barie, N.; Rapp, M.; Ache, H.J. UV crosslinked polysiloxanes as new coatingmaterials for SAW devices with high long-term stability. Sens. Actuat. B Chem. 1998, B46, 97–103.
[4]
Bender, F.; Waechter, L.; Voigt, A.; Rapp, M. Deposition of high-quality coatings on SAW sensors using electrospray. In Proceedings of IEEE Sensors Conference, Toronto, ON, Canada, 22–24 October 2003; 1, pp. 115–119.
[5]
Rapp, M.; Reibel, J.; Stier, S.; Voigt, A.; Bahlo, J. SAGAS: Gas Analyzing sensor systems based on surface acoustic wave devices—An issue of commercialization of SAW sensor technology. In Proceedings of IEEE International Frequency Control Symposium, Orlando, FL, USA, 28–30 May 1997; pp. 129–132.
[6]
Staples, E.J. Dioxin/furan detection and analysis using a saw based electronic nose. In Proceedings of IEEE 1998 Ultrasonics Symposium, Sendai, Japan, 5–8 October 1998; 1, pp. 521–524.
[7]
Staples, E.J.; Matsuda, T.; Viswanathan, S. Real time environmental screening of air, water and soil matrices using a novel field portable GC/SAW system. In Proceedings of the Environmental Strategies for the 21st Century Asia Pacific Conference, Singapore, April 1998; pp. 8–10.
[8]
Frye, G.C.; Martin, S.J. Dual output acoustic wave sensor for molecular identification. In Proceedings of 1991 International Conference on Solid-State Sensors and ActuatorsTRANSDUCERS ’91, San Francisco, CA, USA, 24–27 June1991; pp. 566–569.
[9]
Wessa, T.; Kueppers, S.; Mann, G.; Rapp, M.; Reibel, J. On-line monitoring of process HPLC by sensors. Organ. Process Res. Dev. 2000, 4, 102–106, doi:10.1021/op990080v.
[10]
Frye, G.C.; Martin, S.J.; Cerenosek, R.W.; Pfeifer, K.B.; Anderson, J.S. Portable acoustic wave sensor systems. In Proceedings of IEEE Ultrasonics Symposium, Lake Buena Vista, FL, USA, 8–11 December 1991; pp. 311–316.
[11]
Zhang, P.; Chen, M.; He, P.; Ma, R. Study on surface acoustic wave CO gas sensor based on electroactive polymers. Yadian yu Shengguang/Piezoelectrics and Acoustooptics 2010, 32, 709–712.
[12]
Wang, W.; He, S.; Li, S.; Liu, M.; Pan, Y. Advances in SXFA-coated SAW chemical sensors for organophosphorous compound detection. Sensors 2011, 11, 1526–1541, doi:10.3390/s110201526. 22319366
[13]
Ayala, V.C.; Eisele, D.; Reindl, L.; Josse, F. Temperature stability analysis of LGS for SH-SAW sensor applications. In Proceedings of 2010 IEEE International Frequency Control Symposium, Newport Beach, CA, USA, 1–4 June 2010; pp. 142–145.
[14]
Shimizu, Y.; Terazaki, A.; Sakaue, T. Temperature dependence of SAW velocity for metal film on α-quartz. In Proceedings of IEEE Ultrasonics Symposium, Annapolis, MD, USA, 29 September–1 October 1976; pp. 519–522.
[15]
Henry, E.; Ballandras, S.; Bigler, E.; Marianneau, G.; Martin, G.; Camou, S. Influence of metallization on temperature stability of SAW devices. In Proceedings of IEEE Ultrasonics Symposium, Toronto, ON, Canada, 5–8 October 1997; 1, pp. 221–225.
[16]
Chung, M.-H.; Wang, S.T.; Huang, A.C.S. Study of frequency-temperature characteristics of quartz with various cut angle and metal thickness of electrode. In Proceedings of the 2004 IEEE International Frequency Control Symposium and Exposition, Montreal, QC, Canada, 23–27 August 2004; pp. 617–620.
[17]
Avramov, I.D. Polymer coated rayleigh SAW and STW resonators for gas sensor applications. In Acoustic Waves—From Microdevices to Helioseismology; Beghi, M.G., Ed.; 2011; pp. 521–546. Chapter 23.
[18]
Avramov, I.D.; Voigt, A.; Rapp, M. Rayleigh SAW resonators using gold electrode structure for gas sensor applications in chemically reactive environments. IEE Electron. Lett. 2005, 41, 450–452, doi:10.1049/el:20050432.
[19]
Parker, T.E. SiO2 film overlays for temperature stable surface acoustic wave devices. Appl. Phys. Lett. 1975, 26, 75–77, doi:10.1063/1.88076.
[20]
Yin, J.H.; Wu, W.Q.; Zhang, D.; Shu, Y.A. Temperature characteristics of rayleigh wave in SiO2/128" Y-X LiNbO3 structure. In Proceedings of IEEE Ultrasonics Symposium, Denver, Co, USA, 14–16 October 1987; 1, pp. 237–240.
[21]
Cheng, C.-C.; Chung, C.-J.; Chen, Y.-C.; Kao, K.-S. Temperature effect on the characteristics of surface acoustic wave on SiO2 thin films. In Proceedings of 2004 IEEE Ultrasonics Symposium, Montreal, QC, Canada, 23–27 August 2004; 3, pp. 1884–1887.
[22]
Hawkes, P.W. Sensitivity to external perturbations and the design of detectors. In Advances in Electronics and Electron Physics; Academic Press, Inc.: Sand Diego, CA, USA, 1990; Volume 77, pp. 125–127.
[23]
Parker, T.E.; Montress, G.K. Precision surface-acoustic-wave (SAW) oscillators. In Proceedings of Transaction on UltrasonicsFerroelectrics and Frequency Control, Chicago, IL, USA, May 1988; 35, pp. 342–364.
