Sub-micron metallic electrothermal actuators

The scaling down of electromechanical devices from micrometer scales to nano scales is of great interest. This paper presents fabrication and characterization of sub-micron high aspect ratio metallic electrothermal actuators using a combination of electron beam lithography and electroplating techniques. A 1.2 mum thick SU-8 layer was used as a sacrificial layer and a 1mum thick electron beam lithography-processed polymethyl methacrylate resist was used to form 3:1 aspect ratio sub-micron (minimum feature size of 350 nm) electroplated nickel electrothermal actuators. Such sub-micron electrothermal actuators were characterized by a nanomanipulator system in a scanning electron microscopy system. Electro-thermo-mechanical finite element analysis (FEA) of the actuator using ANSYS was carried out and the FEA results were in good agreement with the measured results. Displacements at the tip of the actuator of 370 nm were reproducibly observed with the applied voltages of 145 mV. This work can be applied to realize more sophisticated nano actuators which can manipulate sub-micron scale objects.