1.5.4 Influence of a Changing Gate Bias on the Sensing Properties of SiC Field Effect Gas Sensors
- 14th International Meeting on Chemical Sensors - IMCS 2012
2012-05-20 - 2012-05-23
- 1.5 Transistor-based Sensors
- C. Bur, M. Bastuck, A. Schütze - Laboratory for Measurement Technology, Saarland University (Germany), M. Andersson, A. Lloyd Spetz - Department of Physics, Chemistry, and Biology, Linköping University (Sweden)
- 140 - 143
Field effect transistors based on silicon carbide have previously been used with temperature cycled operation to enhance the selectivity. In this study the influence of a changing gate bias on the sensing properties of a platinum gate FET has been studied in order to extend the virtual multi-sensor approach. The sensor exhibits gas specific hysteresis when changing the gate bias indicating that additional information regarding selectivity is contained in the transient behavior. Measurements also showed that especially the shape of the sensor signal changes dramatically with different gas exposures (e.g. H2, CO or NH3) during relaxation after step changes of the gate bias. The changing shape primarily reflects the gas itself and not the concentration so that the selectivity of the sensor is increased.