Thermally excited silicon microactuators

Signal conversion from the electrical to the mechanical range in silicon devices is generally complicated by the nonexisting piezoelectric effect in silicon. With other conversion techniques, e.g., via electrostatic or mangnetic forces, it is difficult to realize monolithic integrated actuators. Therefore, materials with different coefficients of thermal expansion combined in a sandwich structure are very attractive basic elements for micromechanical actuators. Using integrated heating elements, IC-compatible monolithic integratable microactuators can be fabricated in a single wafer process. A cantilever-type micromachined silicon actuator has been developed and characterized. The design considerations, the fabrication process, and the experimental results are discussed. (IMT