Modelling of the dynamical behaviour of floating electrode MEMS

In this work we investigate the dynamics of a floating electrode microelectromechanical (MEMS) switch. This is a type of very common MEMS that are actuated electrostatically, i.e., by applying a voltage across the micromechanical structure. A floating electrode MEMS is a novel modification of a capacitive switch where a thin metal layer is deposited on top of the isolating dielectric layer. Although these devices have promising characteristics, this modification alters their behaviour in comparison with conventional MEMS switches. We develop a multi-physics model to simulate the behaviour of the switch and model a number of physical effects that occur in the system and influence its dynamics. We used a fractal as representation of the electrode surface to model the field emission as a result of a local enhancement of the electric field. We provide the comparison of the simulated behaviour with experimental results.