Effect of electron radiation on the dynamic response of Si-based MEMS accelerometers: an in-situ experimental and simulation study

Purpose This study aims to investigate the multiphysics dynamic response of a resonant beam with an insulating substrate under electron irradiation. The focus is on revealing the electromechanical coupling effects between charge accumulation, structural deformation and the device’s micromechanical properties induced by electron beam irradiation, addressing critical reliability gaps in aerospace applications. Design/methodology/approach This paper establishes a Geant4-COMSOL coupling framework to simulate the response of silicon-based microelectromechanical system (MEMS) accelerometer structures under electron beam irradiation of 10–50 keV. Geant4 calculates spatial energy deposition, which COMSOL uses for multiphysics analysis. The authors evaluated varying beam energies (10–50 keV) and substrate materials, validating their predictive models with in situ scanning electron microscopy (SEM). Findings Ionization-induced charge accumulation and transient discharge within the SiO2 substrate drive the resonant beam’s nonlinear periodic oscillations. With increasing energy, structural displacement exhibits a nonmonotonic “decrease–increase–decrease” trend, while oscillation periods shorten. Comparisons with Si substrates confirm the SiO2 insulator’s decisive role in this response. Originality/value Combining in situSEM with cosimulation, this paper unveils the charge-induced discharge mechanisms causing nonlinear MEMS oscillations. These insights offer a crucial theoretical foundation for developing highly reliable, radiation-hardened microsystems for extreme space environments.