Effects of Surface Properties on the Effective Electrical Gap of Microelectromechanical Devices Operating in Contact

摘要

The effective electrical gap between two conducting surfaces sandwiching a thin dielectric layer varies with applied voltage and pressure. Improved methods for measuring and modeling this variation are presented. Optical surface profile measurements of fixed-fixed beams, and capacitance-voltage measurements of a center-tethered structure that eliminates zipping are shown. A compressible contact surface model is used in 2-D simulations of electrostatically actuated beams to capture the surface effects. The simulation fit is good at low voltages but deteriorates at higher voltages. Substrate curvature and electronic effects are investigated but found to be negligible.