Micromechanical comb actuators with low driving voltage

Abstract

Comb actuators with submicrometer-wide suspensions have been fabricated and tested. Measurements proved that they are reliable devices for displacements in the range of several micrometers with a precision in the tens of nanometers. Due to the very flexible suspensions (10 mN m-1) only low voltages-around 20 V- were required for the actuation. As an application, the author have fabricated and characterized an xy microstage which allows precise two-dimensional positioning. The limits of the devices were also tested. A main source of problems is the sticking phenomenon. Depending on the design of the actuator, the movable comb will, at a critical voltage, either stick on the sides of the fixed fingers (side sticking) or on the front ends of the fixed finger (front sticking). Analytical calculations, simulation and measurements are compared.