Development of all metal electrothermal actuator and its applications

Norman A. Fleck W. I. Milne University of Cambridge Department of Engineering Cambridge, CB2 1PZ United Kingdom Abstract. The in-plane motion of microelectrothermal actuator (‘‘heatuator’’) has been analyzed for Si-based and metallic devices. It was found that the lateral deflection of a heatuator made of a Ni metal is about ;60% larger than that of a Si-based actuator under the same power consumption. Metals are much better for thermal actuators as they provide a relatively large deflection and large force, for a low operating temperature and power consumption. Electroplated Ni films were used to fabricate heatuators. The electrical and mechanical properties of electroplated Ni thin films have been investigated as a function of temperature and plating current density, and the process conditions have been optimized to obtain stress-free films suitable for microelectromechanical systems applications. Lateral thermal actuators have been successfully fabricated, and electrically tested. Microswitches and microtweezers utilizing the heatuator have also been fabricated and tested. © 2005 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.1898243]