Effects of Casimir force on pull-in instability in micromembranes

We analyze pull-in instability of electrostatically actuated microelectromechanical systems, and study changes in pull-in parameters due to the Casimir effect. When the size of the device is reduced, the magnitude of the Casimir force is comparable with that of the Coulomb force and it significantly alters pull-in parameters. We model the deformable conductor as an elastic membrane and consider different geometries. Beyond a certain critical size the pull-in instability occurs with zero applied voltage, and the device may collapse during the fabrication process.