Thin-film MEMS molecular sensors are fabricated at temperatures below 110°C on glass substrates. The microelectromechanical structure consists of a surface microiHachined bilayer bridge of phosphorous-doped hydrogenated amorphous silicon and aluminum with a patterned SiO2 layer on the top. Specific binding of DNA to functionalized SiC>2 on the bridge is confirmed using fluorescence microscopy. Microbridges are electrostatically actuated and*"the resonance frequency measurements are performed in vacuum in the initial state after fabrication, after the chemical functionalization of the SiC>2 surface and after DNA immobilization. The sensor is able to detect the functionalization molecular layer, the cross-linker molecular layer, and the DNA molecules attached to the surface through a shift in its resonance frequency. The binding of molecules to the surface results in a shift of the resonance frequency due to contributions from surface stresses and mass loading.
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