Fabrication and characterization of MEMS-based resonant organic gas sniffers

This paper reports on fabrication and characterization of polymer coated high frequency micromechanical resonant silicon nanobalances capable of detection and concentration measurement of volatile organic compounds in gas phase. Devices were fabricated using a single-mask fabrication process and the Shipley-1813 photoresist film used for patterning the devices was kept on the silicon structures to be utilized as the absorbent layer. Thicker and more uniform polymer coatings on resonator surfaces formed using this technique have allowed higher sensitivity and saturation frequency shift compared to previously reported results. Toluene, which is one of the main components of regular gasoline, has been used for characterization of the resonator responses. Based on the measurement results, minimum detectable concentration of toluene in the gas phase for such devices is in the few ppm range.