An Alternative Approach to Investigate V-Shaped Electrothermal Microactuators in Vacuum

In this work, we use a simplified version of Young's solution for the steady-state Joule-heating, that uses temperature dependent thermal and electrical conductivities, to find the temperature and displacement behavior of a V-shaped electrothermal microactuator (ETMA) device. In order to test and validate our approach we performed FEM simulations and actually built an ETMA device by microfabrication. The experimental device displacement was measured in vacuum, with a scanning electron microscope. Our numerical results agree quite well with the FEM simulation and experimental results up to a displacement of (0.8 ± 0.2) μm and applied current of 30 mA. Above 35 mA, an abrupt variation of the resistivity is observed followed by surface degradation at 50 mA and device melting at 52 mA. The validity of our approach is discussed of the device geometry and material parameters.