The design, fabrication and evaluation of a MEMS PZT cantilever with an integrated Si proof mass for vibration energy harvesting

A microelectromechanical system (MEMS) piezoelectric energy harvesting device, a unimorph PZT cantilever with an integrated Si proof mass, was designed for low vibration frequency and high vibration amplitude environment. Pt/PZT/Pt/Ti/SiO2 multilayered films were deposited on a Si substrate and then the cantilever was patterned and released by inductively coupled plasma reactive ion etching. The fabricated device, with a beam dimension of about 4.800 mm x 0.400 mm x 0.036 mm and an integrated Si mass dimension of about 1.360 mm x 0.940 mm x 0.456 mm produced 160 mV(pk), 2.15 mu W or 3272 mu W cm(-3) with an optimal resistive load of 6 k Omega from 2g (g=9.81 m s(-2)) acceleration at its resonant frequency of 461.15 Hz. This device was compared with other demonstrated MEMS power generators.