Ferroelectric Thin Film Diaphragm Resonators for Bio-Detection

In this paper, we have investigated a piezoelectric resonator biosensor based on ferroelectric thin film diaphragm. The diaphragm structure utilizing a flexural vibration mode has been adopted to replace the microcantilever structure in a biosensor. It is an acoustic wave device which can be immobilized with a bio-molecular recognition layer on its surface. Like a microcantilever sensor, the resonance frequency of the diaphragm sensor shifts when the bio-molecular recognition layer reacts with the target species. But a diaphragm sensor has more robust structure comparing with a microcantilever sensor. The responses of the diaphragm biosensor have been simulated using a commercial FEM software package, ANSYS. The prototype devices were fabricated by a conventional method and a MEMS process, respectively. The performance of the sensor was tested and reported.