Long-travel electrothermally driven resonant cantilever microactuators

Silicon microactuators capable of very long travel are described. The design is based on a laterally resonant cantilever, driven by an electrothermal shape bimorph located at the root. Performance characteristics are given for deep structures fabricated in bonded silicon-on-insulator material. Peak-to-peak displacements of more than 500 μm are obtained with cantilevers of 14 mm length, 30 μm width and 100 μm depth using a 20 V drive, when the resonant frequency of the cantilever is matched to the frequency response of the electrothermal transducer. Experimental data are compared with a simple model, and variables affecting the quality factor are discussed. The actuators are shown to be suitable for use in optical scanning systems based on moving waveguides.