A novel external electrode configuration for the electrostatic actuation of MEMS based devices

A novel external electrode concept is introduced and compared with the conventional and often used parallel plate electrode scheme for the electrostatic actuation of micro-electromechanical devices. In contrast to conventional parallel plate actuation, the presented external electrode configuration allows controlled operation of electrostatic actuators over their entire range of motion by avoiding electrostatic instability. The test vehicle for studying deflection versus voltage is a cantilevered beam with a free end, i.e. the worst-case scenario from a stability standpoint. Modeling and fabrication of test devices is discussed and experimental results are presented.