AVS 50th International Symposium
    Organic Films and Devices Tuesday Sessions
       Session OF+EM-TuM

Paper OF+EM-TuM9
Localized Deposition of Thin Films of Conducting Polyaniline on Microhotplates for Chemical Sensing

Tuesday, November 4, 2003, 11:00 am, Room 318/319

Session: Molecular and Organic Films and Devices-Electronics
Presenter: G. Li, National Institute of Standards and Technology
Authors: G. Li, National Institute of Standards and Technology
S. Semancik, National Institute of Standards and Technology
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A procedure for directly processing thin films of conducting polyaniline on MEMs microhotplates is described. The method allows the fabrication of conductometric gas microsensors within microarray platforms. It combines alternating electrochemical and electroless surface polymerization steps along with the localized heating capability of microhotplates to selectively deposit strongly adhering, smooth and compact films on the hybrid (metal/SiO@sub 2@) surfaces of microhotplate sensing elements. The polyaniline films within the arrays can be deposited using different processing parameters and then further fuctionalized electrochemically. In this way, both the film thickness and film conductance can be efficiently fine-tuned to desirable values. Film thickness varies in the sub-micron range and the film conductivities range from insulating up to the order of magnitude 10@super 2@ S.cm@super -1@. In addition, we describe the effect of these film characteristics on the temperature programmed sensing performance of the microsensors to various gases (methanol, H@sub 2@O, CO and NH@sub 3@ etc at 1-1000 ppm concentrations in air).