Modelling and Fabrication of Anti-Stiction Features for Electrostatically Actuated Microsystems

Abstract

In electrostatically actuated microelectromechanical systems (MEMS), the risk of snapping-down moveable beams and membranes increases with decreasing gap between actuation electrodes. Van der Waals forces play a significant role in subsequent stiction of actuated beams with the substrate or other surfaces. In order to enable recovery of the MEMS devices from the snap-down position, the role of size and roughness of the contact surface between anti-stiction bumps and the underlying surface is studied. This paper examines the design parameters of anti-stiction bumps, which allow restoring forces to recover from snap-down position and avoid device failure. Subsequently, the fabrication of these bumps is presented.