Silicon MEMS actuator with no space gap between driving electrodes

Two kinds of new silicon actuators, cantilever and twisted-beam, based on pn diode actuation principle are presented. The space gap that is absolutely needed in conventional electrostatic MEMS actuators is replaced by a depletion layer in reversely-biased pn diode. The strong electric field generated in the depletion layer forces a silicon microstructure to vibrate. The microstructure causes a large deflection at resonance. This actuator eliminates a narrow gap between driving electrodes. Consequently, the silicon actuators maintain to be of high reliability for a long period.