Lead Zirconate Titanate Acoustic Energy Harvester Proposed for Microelectromechanical System/IC Integrated Systems

In this paper, we report on microelectromechanical system (MEMS) energy harvesters with a diaphragm consisting of a 1-µm-thick lead zirconate titanate (PZT) film formed by the sol–gel method. Electrical power can be generated using the piezoelectric effects of the PZT diaphragm that vibrates in acoustic fields. Harvesters with different diaphragm diameters of 1.5 and 2.0 mm were fabricated. The top electrode covered the entire PZT diaphragm. The measured first resonance frequencies of those diaphragms were 6.02 and 5.72 kHz, and the third resonance frequencies were 24.02 and 18.02 kHz, respectively. The measured frequency spectrum indicated that the induced voltages are larger and more widely distributed for the third resonance than for the first resonance. Those devices generated power of 1.1 ×10-11and 5.1 ×10-12W under the irradiation of 100 dB sound pressure at their third resonance frequencies.