Optimization of Electrode Structures of PZT Acoustic Energy Harvesters Fabricated on SOI Substrate

Abstract

This paper reports on the power generation performances of a PZT microelectromechanical system (MEMS) acoustic energy harvester having dual top electrodes to utilize the different polarizations of charges on the surface of a vibrating PZT diaphragm at first resonance. The PZT acoustic energy harvester was fabricated on a silicon-on-insulator (SOI) substrate, and had a diaphragm with a diameter of 2 mm consisting of Al (0.1 μm)/PZT (1 μm)/Pt (0.1 μm)/Ti (0.1 μm)/Si (1.0μm)/ (0.5 μm), and the diaphragm vibrations were excited by sound pressure. The top Al electrodes independently cover the peripheral surface and the central surface of the PZT diaphragm. The peripheral energy harvester generated a power of W, and the central energy harvester generated a power of W at an SPL of 100 dB at 9.95 kHz.