A novel electro-thermally driven bi-directional microactuator

In this study, an electrothermal microactuator for bi-directional motion is designed and fabricated using surface micromachining processes. The in-plane horizontal motion of the device is based on the uneven thermal expansion of the structure with different beam widths, while the out-of-plane vertical motion is driven by electrostatic force through using the principle of lever to allow bending the beam upward and to enlarge the tip deflection. This microactuator has the advantages of CMOS-compatible, low operation voltage, and simple fabrication processes. The expected applications for the proposed devices are micro switches, micromanipulators, micro optical tweezers, etc. Finite element method (FEM) analysis is used to simulate the electrothermomechanical behavior of the device and to demonstrate the feasibility of our design for bi-directional motions under different applied voltages. The relationship between the applied voltage and the displacement is found, and the performance of the presented design has been examined. Finally, the deviation between simulated and measured results is discussed.