Design and Experimental Validation of a New MEMS Long-Stroke Actuator Based on Tunnel-Comb Fingers

A new concept of electrostatic actuation scheme for long-stroke Micro-Electro-Mechanical Systems (MEMS) actuators is introduced. Thanks to the features of Thelma-Double fabrication process recently proposed by STMicroelectronics, we design, fabricate, and test a MEMS actuator based on the new concept of cascaded tunnel-comb fingers. The device is able to achieve a displacement of 30 µm with a footprint of 1x1.1mm
²
at only < 60 V actuation. Preliminary experimental tests well-agree with theoretical predictions, thus proving the design strategy and opening the path to a new class of long-stroke electrostatically driven actuators.