Single Proof Mass Resonant MEMS Accelerometer With Parallel Motion Linkage Amplifier

Abstract

We report on a new architecture and theoretical and experimental feasibility study of a resonant accelerometer, combining a robust single proof mass (PM) design with a compliant parallel motion linkage-type force amplifier. The device, incorporating four effectively oblique force-transmitting links and a resonant sensing beam attached at its ends to two shutters, is distinguished by a simple, manufacturable geometry, purely axial, free from any bending, loading of the vibrating sensing beam, and low parasitic compliance. The device was fabricated from the 25 $\mu$ m thick layer of a silicon-on-insulator (SOI) wafer. The acceleration-dependent frequency of the electrostatically driven 300 $\mu$ m long and 3.8 $\mu$ m wide resonator was measured using capacitive sensing, combined with open or closed-loop excitation scenarios. Consistently with the lumped and the full scale FE models prediction, 760 Hz/g sensitivity of the device, with the $\approx$ 2600 × 2600 $\mu$ m PM, was demonstrated during the $\pm g$ experiment.