Mesoscale MEMS motion transformer and amplifier electrostatically actuated by parallel plate electrodes

We report on the design, fabrication and characterization of a mesoscale microelectromechanical motion transformer and amplifier with integrated actuation. The device incorporates an electrostatic transducer with multiple parallel plate electrodes and an elastic suspension realized as a compliant mechanism, which converts small linear motion of the transducer into mechanically amplified angular motion of a rotating lever. By combining highly efficient small-gap actuation with the motion amplification the device is designed to provide a large, more than 60 µm, lever tip displacement along with a calculated blocking force increasing from the initial value of 0.8 mN up to 26 mN in the maximal stroke configuration when actuated at 150 V. The devices were fabricated from a silicon on insulator (SOI) wafer with (1 1 1) front surface orientation and a 150 µm thick device layer using deep reactive ion etching (DRIE) and their functionality was demonstrated experimentally. Good agreement between the results provided by finite elements analysis and the experimental data was observed. Our results demonstrate an ability to achieve both large displacements and high blocking forces in an electrostatically actuated mesoscale compliant mechanisms. (paper)