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Design of Solid State Array for Simultaneous Potentiometric and Impedance Sensing in Gas Phase
Author(s) -
Polk Brian J.,
Smith J. Anthony,
DeWeerth Stephen P.,
Zhou Zhiping,
Janata Jiri,
Domansky Karel
Publication year - 1999
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199907)11:10/11<707::aid-elan707>3.0.co;2-3
Subject(s) - potentiometric titration , electrical impedance , gas phase , solid state , materials science , phase (matter) , analytical chemistry (journal) , chemistry , electrode , chromatography , electrical engineering , engineering , organic chemistry
A general sensing platform consisting of eight modules has been designed and fabricated in silicon. The operating function of this platform has been divided between a chemical sensing chip (CSC) and an electronic service chip (ESC). The CSC uses a gold metallization and a high temperature silicon nitride as the passivation layer. The smallest feature size on the CSC is 20 µm. It houses eight sensing modules each consisting of a pair of gold electrodes for measurement of impedance of the conducting polymer and a field‐effect transistor for measurement of chemical modulation of the work function of the same polymer. The modules are separated from each other by a patterned 25 µm thick polyimide. The ESC was fabricated by a standard CMOS technology with 1.25 µm feature size. The CSC and ESC chips are connected by flip‐chip bonding which greatly simplifies the packaging. The operation of the combined impedance and work function sensing has been verified by exposure to ammonia in ppm range.