High temperature tolerant diamond-based microelectronic oxygen gas sensor

A new diamond-based microelectronic gas sensor (catalyst/adsorptive-oxide/insulator/semiconductor, CAIS device) has been developed for the detection of oxygen and CO gases. The gas sensing performance, detection mechanisms and activation energy analysis of the sensor for oxygen and CO gases have been analyzed. The gas sensitivity of the sensor is high, repeatable, and reproducible. The response time is in seconds to a small concentration of oxygen and CO gases. The gas detection mechanism of the new sensor is attributed to the change in the oxygen vacancies of the SnOx layer upon oxygen and CO exposure, causing several milliamperes of change in device current. The adsorption activation energy analysis of the sensor reveals small values, 2.8 +/- 0.1 kcal mol(-1) and 1.1 +/- 0.1 kcal mol(-1) for oxygen and CO gases, respectively, confirming the high sensitivity and fast response of this new sensor. The diamond-based CAIS gas sensor could be applied for the detection of oxidizing and reducing gases over a higher and wider temperature range than is currently possible. (C) 1998 Elsevier Science S.A. All rights reserved.