DC-dynamic biasing for > 50x switching time improvement in severely underdamped fringing-field electrostatic MEMS actuators
Date of this Version12-2012
Journal of Micromechanics and Microengineering, Volume 22, Number 12
This paper presents the design and experimental validation of dc-dynamic biasing for >50x switching time improvement in severely underdamped fringing-field electrostatic MEMS actuators. The electrostatic fringing-field actuator is used to demonstrate the concept due to its robust device design and inherently low damping conditions. In order to accurately quantify the gap height versus voltage characteristics, a heuristic model is developed. The difference between the heuristic model and numerical simulation is less than 5.6% for typical MEMS geometries. MEMS fixed-fixed beams are fabricated and measured for experimental validation. Good agreement is observed between the calculated and measured results. For a given voltage, the measured and calculated displacements are typically within 10%. Lastly, the derived model is used to design a dc-dynamic bias waveform to improve the switching time of the underdamped MEMS actuators. With dynamic biasing, the measured up-to-down and down-to-up switching time of the actuator is similar to 35 mu s. On the other hand, coventional step biasing results in a switching time of similar to 2 ms for both up-to-down and down-to-up states.
Nanoscience and Nanotechnology