| Popis: |
In this article a new multielectrode micromachined gas sensor, fabricated by silicon technology, is presented. The device enables different measuring methods which can be used to optimize the properties of resistive gas sensors, e.g. tin oxide sensors. In addition to the conventional interdigitated electrode below the sensitive film, a second interdigitated electrode has been manufactured on top of it. With the use of the two pairs of electrodes it is possible to use different electrical set-ups for resistive measurements. Firstly, the electrodes below and on top of the sensing layer lead to a different sensor behaviour. Therefore, a double sensor array is designed. Secondly, the sensor enables the application of external electric fields e.g. between one electrode and the plane heater. With the use of external electric fields both the resistivity and the sensitivity of the gas sensors could be influenced, significantly. The manufacturing of the silicon based sensor device is described in detail. Results from measurements in different nitrogen dioxide concentrations, applying both measuring principles, are presented and discussed. A qualitative model to explain the sensor properties and suggestions on how to use the new measurement method are presented. |
