Bistability under tension and its use in a threshold force sensor

We report on a first experimental demonstration of a bistability phenomenon in a contactless device suspended using initially curved flexible beams and pulled by electrostatic forces directed along the beams. Devices of several configurations were fabricated from a silicon on insulator (SOI) substrate using a deep reactive ion etching (DRIE) based process and were actuated in-plane in ambient air conditions. We introduce a novel, less sensitive to the fabrication tolerances, operational scenario involving actuation by two parallel-plate electrodes and demonstrate that the bistable device can be used as a force sensor based on a pull-in voltage monitoring.