Modeling and Characterization of Piezoelectric d(33)-Mode MEMS Energy Harvester

Abstract

This paper presents the modeling, fabrication, and characterization of a piezoelectric microelectromechanical systems (MEMS) energy harvester using a d(33) piezoelectric mode. A theoretical analysis and an analytical modeling for the d(33)-mode device were first performed to estimate the output power as a function of the material parameters and device geometry. A PbTiO3 seed layer was newly applied as an interlayer between the ZrO2 and Pb(Zr0.52Ti0.48)O-3 (PZT) thin films to improve the piezoelectric property of the sol-gel spin- coated PZT thin film. The fabricated cantilever PZT film with an interdigital shaped electrode exhibited a remnant polarization of 18.5 mu C/cm(2), a coercive field of less than 60 kV/cm, a relative dielectric constant of 1125.1, and a d(33) piezoelectric constant of 50 pC/N. The fabricated energy-harvesting device generated an electrical power of 1.1 mu W for a load of 2.2 M Omega with 4.4 Vpeak-to-peak from a vibration with an acceleration of 0.39 g at its resonant frequency of 528 Hz. The corresponding power density was 7.3 mW . cm(-3) . g(-2). The experimental results were compared with those numerically calculated using the equations derived from the dynamic and analytical modeling. The fabricated device was also compared with other piezoelectric MEMS energy-harvesting devices.