Viscoelasticity Recovery Mechanism in Radio Frequency Microelectromechanical Switches

Radio frequency microelectromechanical system (RF MEMS) switches require a lifetime of 20 years, during which the devices must operate without failure. During operation, the RF MEMS switches are subjected to prolonged actuation which may induce the problems of charge trapping and mechanical relaxation leading to stiction of the moving membrane. In this paper, we suggest an innovative recovery procedure that allows to avoid the stiction. At regular intervals, the switch is opened and an electrical current forced through the suspended membrane can effectively fully recover the switch. Using the topography analysis, we show that the restoring mechanism is based on the recovery of the mechanical properties of the moving bridge during the current flow. The validity of the procedure is demonstrated with the application of the recovery system on several devices for 20 consecutive cycles.