CAPACITORES MOS APLICADOS COMO SENSORES PARA ANÃLISE DE GASES POLUENTES, EXPLOSIVOS E VENENOSOS

Abstract

This paper reportsthe response of a MOS sensor device to H2 andNH3 gases diluted inN2 or dry air. The sensing elementstructure is a MOS devicewhose gates are made up of Pt, Au, Pd metals.The sensibility of this device depends on the structural characteristics of gates such as theirs, geometries, thickness and the type of metal. The detection principle of the device depends on the induced photocurrent signal. To do this, it developed a gas detection system capable of generating photocurrent signals. A pulsed laser beam wasscanned point by point. Thus, it was obtainedimages corresponding to each representative chemicalatmosphere. The sensorshowed high sensitivity to gases H2 and NH3. Additionally it has been observed that when dry air and N2were used as the test gas carrier, the sensor response showed significant differences with lowest sensitivity for dry air.

Index Terms - Chemical Sensor, Distributed chemical sensing, Field-effect gas sensor, Scanned light pulse technique.