Temperature- and impurity-dependent analytical modeling and experimental validation of single-crystal silicon chevron electrothermal actuator

Chevron electrothermal actuators are widely utilized for their large force output and high versatility in silicon microelectromechanical systems. However, performance estimation is challenging due to nonlinear temperature and impurity concentration dependance of single-crystal silicon’s material properties, which is often neglected. This study proposes an analytical model incorporating these dependencies, particularly a new theoretical model of electrical resistivity valid for wide ranges of impurity concentration and temperature. These material property models were used in the finite element analysis. To validate the models, a chevron electrothermal actuator was fabricated from a silicon-on-insulator wafer and operated in a vacuum. The displacement and temperature distribution were measured using scanning electron microscope and micro-Raman spectroscopy, respectively. At the maximum applied voltage of 10 V, the analysis assuming constant material properties resulted in a discrepancy of approximately 77%, while the proposed model reduced this to less than 9%. The proposed model enables accurate performance estimation.