Experimental analysis of a low controlling voltage tri-electrode MEMS electrostatic actuator for array applications

Abstract

A tri-electeode electrostatic actuator with one moving MEMS electrode and two stationary electrodes (tri-electrode actuator topology) is experimentally tested in this article. The stationary controlling (intermediate) electrode is perforated and below the moving MEMS electrode, while the common electrode is further below. Numerical simulations were performed to discover the optimal design parameters for a tri-electrode electrostatic actuator in comparison to a conventional two electrode electrostatic actuator. A silicon-based moving MEMS electrode was designed with a relatively linear spring constant, and the controlling intermediate and primary stationary electrodes were fabricated on either side of a quartz substrate instead of free space to simplify their fabrication. The measurement results showed that the tri-electrode topology can control the displacement of the MEMS with a lower controlling voltage and with extended controllable range before pull-in instability, compared to the conventional actuator. Simulations and measurements showed that the controlling voltage was reduced by 2.6 times compared to the conventional actuator design employing a bipolar driven intermediate electrode, while the controllable deflection range before pull-in was elevated by 33%. This tri-electrode design offers benefits for applications in need of arrays of electrostatic actuators such as deformable mirrors.

Impact of Solid Materials in the Gap Space between Driving Electrodes in a MEMS Tri-Electrode Electrostatic Actuator

“…The numerical studies in this work build upon experimentally verified simulations of a device with quartz material in the gap between the intermediate and the primary electrodes [28]. However, the experimental simulator did not involve an optimized trielectrode design to enable the best FOM performance, and rather was created to verify the numerical simulation method.…”

“…However, in regard to the tri-electrode actuator topology [26][27][28], the aim is to reduce the control voltage and also improve the range of motion. This method can be applied to existing parallel-plate electrostatic actuator design, with very minor modifications in the design and fabrication.…”

Low-Voltage Tri-Electrode Electrostatic Actuator Using Solid Gap-Spacing Materials

“…The tri-electrode consists of one perforated intermediate electrode with VI varying voltage and a solid electrode with fixed VP voltage. Simulation studies alongside experimental studies were carried out to show the performance of the actuator [2]. It was also shown that using a thicker gap-spacing material (ε r > 1) between the stationary electrodes (compared to filling with air/vacuum, ε r = 1) helps to simplify the fabrication while preserving the higher actuator's performance compared to the conventional topology.…”

A Novel MEMS Actuator Driven with a Low DC Voltage

“…Several studies have been conducted over two decades to solve this problem, (14)(15)(16)(17)(18)(19)(20)(21)(22)(23) however none of them has achieved a displacement larger than 6 μm at a dc driving voltage typically used in MCU boards. We have focused on this matter and proposed a revolutionary structure that overthrows the conventional structures of electrostatic microactuators, which were considered to be unable to drive large amounts of displacement.…”