EVALUATION OF GAS-MIXTURES WITH HIGH-TEMPERATURE GAS SENSORS BASED ONSILICON-CARBIDE

Field-effect devices with a catalytic metal gate are operated as gas s ensors over a large temperature range by the use of 6H-silicon carbide (bandgap 2.9 eV) instead of silicon (1.1 eV) as the semiconducting ma terial. We have produced metal-silicon dioxide-silicon carbide (MOSiC) capacitors with platinum as the gate metal that can be operated above 800-degrees-C. The sensitivity of the Pt-MOSiC devices to hydrogen an d hydrocarbons was tested in various oxygen atmospheres. The response to mixtures of hydrogen and saturated hydrocarbons indicated the exist ence of two different sensing mechanisms.