Effect of the acting electrode position on a microcantilever dynamic response under different excitation modes

摘要

In this paper, the effect of the acting electrode position on the dynamic behavior of a polysilicon microcantilever is investigated by considering different oscillating modes. The oscillation of structures in higher bending modes is used to increase the quality factor and to decrease the loss of energy during oscillation. The tests are performed in ambient conditions as well as in vacuum. The position of the acting electrode changes the velocity and amplitude of oscillations. A significant influence is determined on the quality factor and on the loss of energy, those are improved if the structures vibrate in the second or third bending modes for the same position of the acting electrode. As the acting electrode position is moved from the cantilever free-end toward to the anchor, the resonator oscillates to a new deflected position and the quality factor is changed. The results are useful for MEMS designers because the sensor/actuator response can be modified only by changing the position of the acting electrode without any significant modification on the fabrication process.