The study presents an ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.18 μm complementary metal oxide semiconductor (CMOS) process. The integrated sensor chip consists of a heater, an ammonia sensor and a readout circuit. The ammonia sensor is constructed by a sensitive film and the interdigitated electrodes. The sensitive film is zirconium dioxide that is coated on the interdigitated electrodes. The heater is used to provide a working temperature to the sensitive film. A post-process is employed to remove the sacrificial layer and to coat zirconium dioxide on the sensor. When the sensitive film adsorbs or desorbs ammonia gas, the sensor produces a change in resistance. The readout circuit converts the resistance variation of the sensor into the output voltage. The experiments show that the integrated ammonia sensor has a sensitivity of 4.1 mV/ppm.
References
[1]
Gardner, J.W.; Varadan, V.K.; Awadelkarim, O.O. Microsensors MEMS and Smart Devices; Jon Wiley & Son Ltd.: Chichester, UK, 2001.
[2]
Lee, Y.S.; Song, K.D.; Huh, J.S.; Chung, W.Y.; Lee, D.D. Fabrication of clinical gas sensor using MEMS process. Sens. Actuators B 2005, 108, 292–297.
[3]
Yoon, J.H.; Lee, H.J.; Kim, J.S. Ammonia gas-sensing characteristics of Pd Doped-WO3. Sens. Lett. 2011, 9, 46–50.
[4]
Carquigny, S.; Sanchez, J.B.; Berger, F.; Lakard, B.; Lallemand, F. Ammonia gas sensor based on electrosynthesized polypyrrole films. Talanta 2009, 78, 199–206.
[5]
Patois, T.; Sanchez, J.B.; Berger, F.; Rauch, J.Y.; Fievet, P.; Lakard, B. Ammonia gas sensors based on polypyrrole films: Influence of electrodeposition parameters. Sens. Actuators B 2012, 171–172, 431–439.
Llobet, E.; Ivanov, P.; Vilanova, X.; Brezmes, J.; Hubalek, J.; Malysz, K.; Gràcia, I.; Cané, C.; Correig, X. Screen-printed nanoparticle tin oxide films for high-yield sensor microsystems. Sens. Actuators B 2003, 96, 94–104.
[8]
Kao, P.H.; Dai, C.L.; Hsu, C.C.; Lee, C.Y. Fabrication and characterization of a tunable in-plane resonator with low driving voltage. Sensors 2009, 9, 2062–2075.
[9]
Dai, C.L.; Hsu, H.M.; Tsai, M.C.; Hsieh, M.M.; Chang, M.W. Modeling and fabrication of a microelectromechanical microwave switch. Microelectron. J. 2007, 38, 519–424.
[10]
Satsuma, A.; Shimizu, K.; Hattori, T.; Nishiyama, H.; Kakimoto, S.; Sugaya, S.; Yokoi, H. Polytungstate clusters on zirconia as a sensing material for a selective ammonia gas sensor. Sens. Actuators B 2007, 123, 757–762.
[11]
Deshmukh, S.B.; Bari, R.H.; Patil, G.E.; Kajale, D.D.; Jain, G.H.; Patil, L.A. preparation and characterization of zirconia based thick film resistor as a ammonia gas sensor. Int. J. Smart Sens. Intell. Syst. 2012, 5, 540–558.
[12]
Sedra, A.S.; Smith, K.C. Microelectronic Circuits; Oxford University Press: Oxford, NY, USA, 1998.
[13]
Gavrilov, V.Y.; Zenkovets, G.A. Formation of the pore structure of zirconium dioxide at the stage of gel aging. Kinet. Catal. 2000, 41, 561–565.
[14]
Liu, X.L.; Pappas, I.; Fitzgerald, M.; Zhu, Y.J.; Eibling, M.; Pan, L. Solvothermal synthesis and characterization of ZrO2 nanostructures using zirconium precursor. Mater. Lett. 2010, 64, 1591–1594.
[15]
Yang, M.Z.; Dai, C.L.; Wu, C.C. A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip. Sensors 2011, 11, 11112–11121.
[16]
Liu, M.C.; Dai, C.L.; Chan, C.H.; Wu, C.C. Manufacture of a polyaniline nanofiber ammonia sensor integrated with a readout circuit using the CMOS-MEMS technique. Sensors 2009, 9, 869–880.
