A Piezoelectric MEMS Loud Speaker Based on Ceramic PZT

This paper presents a ceramic PZT based piezoelectric MEMS speaker that can generate high sound pressure level (SPL) with small driving voltage. By using wafer bonding and chemical mechanical polishing techniques, the MEMS speaker is made of ceramic PZT that is only about 5 μm thick. With a chip size of 6.7 mm by 6.7 mm, the fabricated speaker generated a maximum SPL of 108 dB at the resonance of 8.2 kHz under just 5 V. This SPL value is comparable with those of conventional speakers or microspeaker arrays with similar size.