This paper presents a novel, highly sensitive condenser microphone with a flexure hinge diaphragm. We used the finiteelement
analysis (FEA) to evaluate the mechanical and acoustic performance of the condenser microphone with a hinge
diaphragm. And we fabricated the miniature condenser microphones with area of 1.5 mm x 1.5 mm. From the simulation
and measurement results, we confirmed that the maximum displacements at the center of flexure hinge diaphragms are
several hundred times, compared with flat diaphragms. Moreover, the miniature microphones have obtained -3 dB
bandwidth of nearly 20 kHz by proper design of the flexure hinge diaphragms.
The MEMS (micro-electro-mechanical systems) microphone enables the manufacturing of small mechanical
components on the surface of a silicon wafer. The MEMS microphones are less susceptible to vibration because of the
smaller diaphragm mass and an excellent candidate for chip-scale packaging. The PMN-PT materials itself exhibit
extremely high piezoelectric coefficients and other desirable properties for an acoustic sensor. In this paper, we present a
piezoelectric MEMS microphone based on PMN-PT single crystal diaphragm. The fabrication process including dry
etching conditions and scale-factored prototype is presented. In particular, this paper introduces the design of a PMN-PT
single crystal diaphragm with interdigitated electrode.