Electrostatic polysilicon microrelays integrated with MOSFETs

The fabrication and characterization of electrostatically-driven microrelays integrated together with IC components are presented. The mechanical part of the microrelays consists of a polysilicon-silicon nitride-polysilicon microbridge realized by sacrificial layer technology and allowing one to separate the actuation and the working circuit. The main operational parameters are actuation voltages in the 50 V to 75 V range depending on the beam lengths of the relays; switching frequencies up to 20 kHz with negligible electrical cross-talk between actuation and working port; a maximum measured frequency of 75 kHz without damaging the microrelay; a rise time of 4 μs and a fall time of 1 μs. First experiments in nitrogen atmosphere have shown that the relay is able to cycle over 10⁹ times with no significant changes in its electromechanical properties