Microhotplate Gas Sensor Arrays

Published

November 18, 1999

Author(s)

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

Abstract

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.

Citation

Proceedings of SPIE

Volume

3857

Pub Type

Journals

Download Paper

https://doi.org/10.1117/12.370293

Keywords

array, chemical vapor deposition, CO, gas sensor, methanol, microhotplate, SnO₂, tin oxide

Citation

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], https://doi.org/10.1117/12.370293 (Accessed March 18, 2025)