Dielectric related effects in micromachined electrostatic actuators

Abstract

The paper discusses the advantages of using electrostatic actuation at the microscale and the issues associated with the use of narrow air gaps (hundreds of Angstroms to hundreds of microns), thin dielectric films (few thousands of Angstroms) and very high fields (over 2 MV/cm) in microdevices. The attention is focused on the touch-mode electrostatic actuators. Studies on the effect of the dielectric and electrode material, of the ambient humidity and gas, of the driving signal and the operating mode are reported. The failure modes are identified and some solutions are given. Electrostatic microactuators operating without failures for over 40 million cycles are reported. Areas of further study are identified. The paper serves as an invitation to the members of the DEI Society to join the efforts of the MEMS community in the study and development of micro-and meso-scale electrostatic actuators.