A Novel Electrostatic Vertical Actuator Fabricated in one Homogeneous Silicon Wafer Using Extended SBM Technology

Abstract

This paper presents a novel process for fabricating electrostatic vertical actuators in single-crystal silicon, using only one homogeneous (111) silicon wafer and an extended version of the Surface/Bulk Micromachining (SBM) technology. The developed process uses 2 photomasks, but all critical patterns including moveable electrodes, fixed electrodes, and planar gaps are defined in the first photomask, hence ensuring that the process is robust to alignment errors. The fabricated vertical actuator has 5 µm thick upper electrodes, 11 µm thick lower electrodes, a 1 µm vertical overlap and a 6 µm planar gap between the upper and lower electrodes.