Design considerations for optimization of pull-in stability margin in electrostatic N/MEM relays

This study aims at providing guidelines for designing electrostatically-actuated micro/nanoelectromechanical relays with a broad operating margin around the supply voltage VDD. Whereas it is tempting to focus mainly on minimizing the first pull-in voltage (Vpi) in order to enable a low VDD, special attention should be paid to the so-called catastrophic pull-in (Vcpi), which corresponds to the movable electrode collapsing onto the actuating electrode for a sufficiently large overdrive. Based on analytical and finite element analysis (FEA) modeling, we study the dependence of a functionality margin defined as (Vcpi-Vpi) versus the size and position of the actuating electrode with respect to the movable structure.