Design of electrothermally actuated micromirror for low power switching applications

In this work, a micro mirror that is powered by electrothermal forces and is capable of producing large displacements in any direction is proposed. COMSOL Multiphysics is used in order to explore and simulate the electrical, thermal and most importantly the mechanical behavior of the mirror system. Because of its small size, a micromirror made of silicon is capable of producing large deflections. Aluminum, polysilicon, and silicon dioxide are the three components that make up electro thermal actuators. In order to carry out its tasks, the actuator makes use of joule heating and thermal expansion. The application of voltage in between the anchors results in thermal expansion, which in turn induces angular rotation as well as vertical displacement, both of which may be used for tip tilt motion. The device has an average deflection of 1.78 micrometres in either direction for an input voltage of 1 volt. The designed actuator can be used for low switching applications if the micromirror is deflected under controlled conditions.