Negative capacitance for control of gap-closing electrostatic actuators

Negative capacitance extends the stable range of a gap-closing actuator beyond the voltage-controlled and the charge-controlled limits. One parallel-plate actuator design stably deflects more than 80% of the gap despite the presence of destabilizing parallel capacitance. A second design, in agreement with a two-degree-of-freedom model, is stabilized while tipping and achieves a maximum deflection of 1.4 /spl mu/m or 91% of the gap using less than 3 V.