Design and Simulations of a Novel Stiction-Free Laterally Actuated NEM Relay With Flexible Source-Drain Contact

Abstract

A novel design for laterally actuated nanoelectromechanical (NEM) relays with flexible source-drain contact is presented. The design uses a thin curved source that can provide expandable contact area between the source and the drain in ON-STATE position. The presence of the thin film curved source creates a local nonlinear stiffness in addition to the main stiffness of the source beam. This additional stiffness not only controls the contact area with over-drive voltage after the pull-in, but can also generate repulsive force when the actuation voltage is removed to separate the two contacting surfaces. The additional repulsive force creates a “peel-off” separation mechanism and can overcome relatively large adhesion forces. Finite element simulations are used to verify the applicability of this design and ANSYS® APDL structural solver and contact technology is used to determine the nonlinear stiffness of the curved source and also to simulate the stiction and repulsive forces generated in the curved source. Curved source structures with different curvatures are simulated to examine the applicability of the design idea in overcoming the adhesion between source and drain. FEM results demonstrate that secondary structural stiffness created at the source-drain contact can overcome large adhesion stress and allow the separation in a peel-off mechanism after the actuation voltage is removed.