Temperature-dependent material properties of Z-shaped MEMS thermal actuators made of single crystalline silicon

MEMS thermal actuators have been employed in a broad range of applications, often operating in different environments (e.g. vacuum, air or liquid). Since the involved heat dissipation mechanisms are different in different operating environments, the device performances are expected to be different. In this paper, we report experimental measurement and multiphysics modeling of device performance metrics of a recently introduced thermal actuator, the Z-shaped thermal actuator, including temperature distribution, electric resistance and displacement in both air and vacuum environments. The temperature measurement was based on Raman scattering in air. Fully 3D multiphysics (coupled thermo-electro-mechanical) simulations were performed to treat both air and vacuum environments. Heat conduction through air to neighboring devices is important, while heat convection to air is negligible. The experimental and modeling results agreed well, which demonstrated the accuracy of the temperature-dependent material properties used in the modeling. Fully 3D multiphysics modeling combined with valid material property parameters will enable the exploration of the design space and the optimization of performances of the MEMS thermal actuators for different operating environments. (paper)