CMOS Integrated Nanocrystalline SnO2 Gas Sensors for CO Detection

In this work, we present gas sensors based on nanocrystalline SnO2 ultrathin films, which were integrated on microhotplate chips fabricated by CMOS technology. The gas sensitive films, with a thickness of 50nm, were deposited on the microhotplate by a spray pyrolysis process. The CMOS integrated sensor resistance was significantly decreased in the presence of carbon monoxide. A sensor response of up to 50% is achieved at an operating temperature of 375̊C. The microhotplate chips presented here enable 3D integration of different gas sensing systems by through-silicon-via technology. Such 3D-integrated nanosensors are promising candidates for building smart gas sensor devices for daily life applications.