MEMS-based Ethanol Sensor Using Zinc Oxide Nanostructured Films

An ethanol sensor incorporating nanostructured zinc oxide film and silicon micromachining is reported. A salient feature of the sensor is its lower operating temperature which has been achieved due to the use of nanostructured material as sensing layer. A suitably designed nickel microheater has been integrated with the sensor. The optimum temperature of operation for ethanol sensing was found to be 100 °C, though the sensor could operate at temperature as low as 50 °C with reduced sensitivity. The power consumption, at an operating temperature of 100 °C, was 180 mW while at 50 °C, it is only 90 mW. The sensor is capable of giving detectable response for concentrations of ethanol vapor as low as 10 ppm. KeywordsZinc films; Zinc oxide nanocombs; Thermal evaporation; Lithography; Ethanol sensor.

[1]  Chenglu Lin,et al.  Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors , 2004 .

[2]  Hiranmay Saha,et al.  Fast response methane sensor using nanocrystalline zinc oxide thin films derived by sol–gel method , 2007 .

[3]  J. W. Gardner,et al.  Design and optimisation of a high-temperature silicon micro-hotplate for nanoporous palladium pellistors , 2003, Microelectron. J..

[4]  J. D. Sternhagen,et al.  Development of a micromachined hazardous gas sensor array , 2003 .

[5]  M. Gaitan,et al.  Tin oxide gas sensor fabricated using CMOS micro-hotplates and in-situ processing , 1993, IEEE Electron Device Letters.

[6]  Djemel Lellouchi,et al.  The advent of MEMS in space , 2003, Microelectron. Reliab..

[7]  Giorgio Sberveglieri,et al.  Stable and highly sensitive gas sensors based on semiconducting oxide nanobelts , 2002 .

[8]  W. Y. Wang,et al.  Improvement in gas sensitivity of ZnO thick film to volatile organic compounds (VOCs) by adding TiO2 , 2004 .

[9]  Wan-Young Chung,et al.  Tin oxide microsensor for LPG monitoring , 1994 .

[10]  Elvira Fortunato,et al.  Influence of the deposition conditions on the gas sensitivity of zinc oxide thin films deposited by spray pyrolysis , 2001 .

[11]  Carles Cané,et al.  Thermal and mechanical analysis of micromachined gas sensors , 2003 .

[12]  Carole Rossi,et al.  Theoretical and experimental study of silicon micromachined microheater with dielectric stacked membranes , 1997 .

[13]  Johnny K. O. Sin,et al.  A low-power CMOS compatible integrated gas sensor using maskless tin oxide sputtering , 1998 .

[14]  Pierre Temple-Boyer,et al.  Realization and performance of thin SiO2/SiNx membrane for microheater applications , 1998 .

[15]  Hyung-Gi Byun,et al.  Sensing characteristics of nano-network structure of polypyrrole for volatile organic compounds (VOCs) gases , 2006, 2006 5th IEEE Conference on Sensors.

[16]  Javier A. Salcedo,et al.  On-chip electrostatic discharge protection for CMOS gas sensor systems-on-a-chip (SoC) , 2006, Microelectron. Reliab..

[17]  M. Zaghloul,et al.  Integrated CMOS surface acoustic wave gas sensor: design and characteristics , 2003, Proceedings of IEEE Sensors 2003 (IEEE Cat. No.03CH37498).

[18]  Carles Cané,et al.  A micromachined solid state integrated gas sensor for the detection of aromatic hydrocarbons , 1997 .