High-frequency large-deflection electrostatic diaphragm actuators with maximized volume displacement

Abstract

This paper demonstrates electrostatic (ES) actuators with high frequency diaphragms (> 90 kHz), large deflection (> 8 μm), high volume displacement, and reliable operation using a new fabrication process and device structure. Electrode gaps of up to 9.58 μm have been fabricated with a filleted electrode shape which allows the pulled-in diaphragm to follow the curved profile of the electrode, displacing 100% of the air gap volume. The filleted electrode actuators have been dynamically actuated for over 212 hours without any diaphragms breaking or sticking. In contrast flat electrode diaphragms broke after < 2 minutes of actuation.