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Microhotplate Gas Sensor Arrays



Richard E. Cavicchi, Stephen Semancik, R M. Walton, B Panchapakesan, Don L. DeVoe, M I. Aquino-Class, J D. Allen, John S. Suehle


In this work, micromachining and planar processing has been used to achieve solid state sensing devices with lower power consumption at lower cost. The small size brings new advantages for chemical selectivity as well: multi-element whose time-varying signals can be interpreted using pattern recognition methods. The device platform is a microhotplate, consisting of a built-in heater, thermometer, and electrodes to probe the sensing films. Microhotplates are fabricated using CMOS-compatible technologies, enabling on-chip circuitry for multiplexing and signal amplification. Millisecond temperature changes in the range of 20 degrees C to over 500 degrees C are employed to alter the adsorption/desorption and reaction kinetics between the gas and sensor surface to create fingerprints in the dynamic conductometric resposes for different analytes. Elevated microheater temperatutes are used to for activation of selected-area CVD processes to deposit sensing films, for sintering of catalytic layers, and for reconditioning the sensors. In this report we present the first results from a 36 element array of microhotplate devices. The combination of multiple sensor materials and real-time changes in reaction kinetics occurring on each sensor provide high information content response data which can be analyzed to yield gas-phase concentration data.
Proceedings of SPIE


array, chemical vapor deposition, CO, gas sensor, methanol, microhotplate, SnO<sub>2</sub>, tin oxide


Cavicchi, R. , Semancik, S. , Walton, R. , Panchapakesan, B. , DeVoe, D. , Aquino-Class, M. , Allen, J. and Suehle, J. (1999), Microhotplate Gas Sensor Arrays, Proceedings of SPIE, [online], (Accessed June 18, 2024)


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Created November 18, 1999, Updated November 10, 2018