Development of all metal electrothermal actuator and its applications

The in-plane motion of microelectrothermal actuator ("heatuator") has been analysed 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 optimised to obtain stress-free films suitable for MEMS applications. Lateral thermal actuators have been successfully fabricated, and electrically tested. Microswitches and microtweezers utilising the heatuator have also been fabricated and tested.