A Stress-Induced Thermal actuator for Optical Purpose

We present a micromachined, stress-induced, thermal bimorph actuator for optical purpose. Piston motions of more than 3um are demonstrated by FEM simulation. Upon the release from the substrate, the actuators lift off the substrate due to a large built-in bending moment arising from the compressive residual stress in the poly-silicon layer and tensile residual stress in the metal layer. Large displacement and low operating voltage (<2V) are obtained simultaneously.