Dynamic response of a polysilicon microbridge driven by different electrostatic forces

The paper presents the effect of operating parameters on the dynamic behavior of a polysilicon microbridge tested in ambient conditions and in vacuum. During experimental investigations, an AC harmonic load of an amplitude equal by 5 V is constantly applied on vibrating structure, and the DC offset signal is increased. The DC voltage has influence on the prestress position of vibrating structure with effect on the velocity and amplitude of oscillation. As the DC voltage is increased, the prestress position of microbridge is modified and the velocity of oscillation increases, respectively. The quality factor and the loss of energy during oscillation are determined for a microbridge oscillated in air and vacuum under different electrostatic forces. As the DC voltage increases, the microbridge oscillates to a new deflected position and the quality factor is changed. A significant influence of DC voltage on quality factor is determined of sample oscillated in vacuum based on internal dissipation energy. The experimental values are validated by the numerical and analytical results.