Detection of gases with arrays of micromachined tin oxide gas sensors

Abstract A good detection of NO 2 , CO and toluene at low concentrations has been carried out by using a micromachined gas sensor array composed of three devices working at different temperatures. The structure is fabricated using standard microelectronic technologies and tin oxide layers as sensitive material. The total power consumption of the array is in the range of 150 mW and a good uniformity of temperature is achieved, thanks to a silicon plug placed under the active area of each sensor. With this device type, it is possible to discriminate gases in a mixture when each array microsensor is heated at a proper temperature.