Utilizing mechanical adhesion force as a high contact force in a MEMS relay

Abstract

High contact force in a microelectromechanical systems (MEMS) relay is known to be the most important factor in achieving low contact resistance. Achieving a high contact force in an electrostatically-actuated MEMS relay usually requires high actuation voltage to exert a high electrostatic force. In this paper, for the first time, we demonstrate the successful use of a mechanical adhesion force as a high contact force for realizing an extremely low contact resistance, even at a low actuation voltage of 3.8 V. To maximize the mechanical adhesion, we designed a suitably-large contact area (100 μm × 100 μm) in the MEMS relay and a detachment spring structure to separate the two electrodes that were in contact with one another by only the mechanical adhesion force, thereby enabling the MEMS switch to perform multiple switching operations. The proposed MEMS relay exhibited an extremely low contact resistance of 4.9 mΩ with only the mechanical adhesion force after we applied an actuation voltage of 3.8 V, and it achieved a retention time of 105 s because of stable mechanical contact. Through this experiment, we verified that the mechanical adhesion force can provide an efficient source for generating high contact force in the MEMS relay.