High quality factor silicon cantilever transduced by piezoelectric lead zirconate titanate film for mass sensing applications

In this paper, we present a single-crystal silicon cantilever integrated with piezoelectric lead zirconate titanate (PZT) film as both an actuator and a sensor for resonant-based mass sensing applications. The pattern size of the PZT film was restricted to the fixed end of the cantilever to suppress intrinsic energy loss from the PZT film and multi layered structure. The energy dissipation mechanism of the cantilever was discussed. The mechanical quality factor (Q-factor) and sensitivity dependence on the cantilever's geometry were investigated. It was found that the Q-factor and sensitivity of the cantilever can be markedly improved by partially covering the cantilever with the PZT film. Under atmospheric pressure, excellent Q-factor of 808 was achieved by a 30-μm-wide 100-μm-long cantilever at fundamental resonant mode. Under reduced pressure, the proposed cantilever exhibits Q-factor several times greater than that of our previous reported fully PZT-covered cantilever. Moreover, high-mode vibration was successfully demonstrated using the proposed structure for the pursuit of higher mass-detection sensitivity.