Characterization and improvement on quality factor of microcantilevers with self-actuation and self-sensing capability

An integrated microcantilever with improved quality factor (Q-factor) was proposed and characterized for resonant based mass sensing applications. Piezoelectric lead zirconate titanate (PZT) thin film actuator was designed at the cantilever's fixed end to compress energy dissipation and other negative effects. Resonant frequency of the cantilever can be detected by a piezoresistive gauge for impedance matching with electric circuits. The cantilever exhibits excellent Q-factor under atmospheric pressure. Finite element analysis indicated that signal to noise ratio of the piezoresistive gauge was improved by using the isolation holes to reduce initial stress caused by PZT deformation. While, the Q-factor's degradation by isolation holes was identified only by the smallest cantilever. For bio-chemical applications which must be carried out under low pressure or vacuum, better device sensitivity can be expected if geometry of the isolation hole is further optimized to improve the cantilever's stiffness.