Sensor Based on the Mode-Localization Effect in Electrostatically-Coupled MEMS Resonators Fabricated Using an SOI Process

The mode-localization effect exhibited in electrostatically-coupled microelectromechanical systems (MEMS) resonators was demonstrated using a pair of rectangular clamped-clamped beams that were fabricated using a silicon-on-insulator (SOI) based process. The response of the amplitude ratio of the resonating beams at the fundamental mode frequencies to a change in the stiffness of one of the beams was characterized. Beams with different widths were fabricated and tested, with up to 13 times improvement in sensitivity to relative stiffness change being reported for a device with 20 mu m widths, compared to 10 mu m widths. In addition, when compared to the state-of-the-art, the devices reported up to 2.8 times improvement in sensitivity.