Digital MOS-transistor-based microhotplate array for simultaneous detection of environmentally relevant gases

A monolithic gas sensor system is presented, which, for the first time, includes on a single chip an array of three metal-oxide-coated microhotplates with integrated MOS-transistor heaters, as well as specifically designed digital circuitry. An octagonal-shape microhotplate design with MOS-transistor heaters has been adopted for the three gas sensors. The integrated circuitry includes a programmable digital temperature regulation, digital sensor readout units and a standard serial interface. Distinct SnO/sub 2/-based sensing materials with different noble-metal dopings were tested. First chemical measurements with CO and CH/sub 4/ have been conducted, the results of which are presented in this paper.