Bouncing dynamics of resistive microswitches with an adhesive tip

This paper provides a detailed analysis of the dynamic response of a resistive microswitch. The analysis has been carried out by modeling the microswitch as a cantilever beam, according to the Euler-Bernoulli theory, and considering the damping interaction of the moving beam with the surrounding fluid. Attention has been given to the bouncing of the beam tip on the substrate upon actuation. A general adhesive-repulsive force has been applied at the tip of the beam to model its interaction with the substrate, where the attractive contribution is described by a van der Waals-like term and the repulsive contribution by a classical linear elastic springlike term. The resulting problem has been solved using a second-order-accurate finite difference scheme. It is shown that by tuning the adhesive interaction at the tip/substrate interface the number and amplitude of the bounces can be significantly reduced in favor of the system reliability and performance. Also design maps have been proposed to estimate the actual switching time and bouncing dynamics as a function of the adhesive interaction, applied actuation voltage, and of the geometry of the microdevice. These maps can be useful in a preliminary design of the system.