Thermal resonant zeolite-based gas sensor

New concept of microfabricated thermal resonant gas sensor comprising of a cantilever-like thermal device covered with a selective zeolite layer associated to heat feedback electronics is presented. Sensing principle exploits the thermal resonant frequency shift caused by mass variations upon gas adsorption in the zeolite layer; the proof-of-concept is demonstrated by selective adsorption of water and ethanol in hydrophilic FAU type zeolite layer. Hollow silicon supporting structures were fabricated in order to enhance the zeolite to silicon mass ratio, thus improving the relative thermal mass variation under gas adsorption.