The effect of sensing area position on the mechanical response of mass — Detecting cantilever sensor

This paper presents the effect of sensing area position on the mechanical response of mass -detecting cantilever sensors fabricated from polysilicon. The scope is to improve the reliability design of mass - detecting sensors that implies high sensitivity and small dissipation energy. The position of the detecting plate, that is the sensing area, is moved from the cantilever free-end toward to the beam anchor and, as a consequence, different sensitivities of the mass - detecting sensor are obtained. The sensitivity and the loss of energy during oscillations are measured using a vibrometer analyzer. The resonant frequencies responses of mass - detecting microcantilevers for different positions of the sensing area are monitored. The experimentally obtained curves of resonant frequency response are used to estimate the quality factor and the dissipation energy. The total loss of energy is estimated for cantilevers oscillated in air, considering the air damping, the loss of energy given by anchor and the intrinsic dissipation energy. The experimental results of the resonant frequency are confirmed by the finite element analysis. Different sensitivities at paddle cantilevers are obtained using finite element analysis for the cases of point-mass deposition and layer-mass deposition.