Stiffness-Tunable Microstructures Based on Electrothermal Bimorph Beams

Robust and light-weighted microstructures are highly desired for various MEMS devices. Thin-film structures are light-weighted, but often suffer from low stiffness. In this abstract, a microstructure with tunable and enhanced stiffness is proposed for the first time. The stiffness-tunable microstructure is based on an electrothermal bimorph beam with an arched transverse cross-section. The concept, exemplified structure design and fabrication method of the proposed structure are presented. Both simulation and test results show that the stiffness of such a structure can be continuously changed more than 25 times by tuning the applied voltage from 0 to 7 V. This method provides a simple approach to stiffen thin-film microstructures.