Micro fabrication development of a vibration-based sputtered PZT thin film micro energy harvester

Abstract

We developed a micro fabrication process of vibration-based sputtered PZT micro energy harvester with a proof mass. A PZT film as a piezoelectric material is formed on a cantilever by using sputtering. An electric power is generated because of piezoelectric effect when the cantilever is bended and stressed. The device is fabricated on a Si substrate by MEMS techniques. The cantilever had 1200 m in length, 600 m in width, and 50 m in thickness on the Si substrate. Also, a PZT thin film free standing cantilever was successfully fabricated. A proof mass with 0.42 mg in weight was fabricated on both top of Si substrate cantilever and PZT thin film free standing cantilever. Dynamic and static frequency characteristics and output power generation were experimented by using a shaker and a network analyzer for characterizing the device. The resonant frequency of the Si cantilever was 8.81 kHz. We achieved 418 pW output power at the resonant frequency.I.

Design optimization of vibration energy harvesters fabricated by lamination of thinned bulk-PZT on polymeric substrates

“…The displacement of each block (b1, b2) was calculated from equation ( 9), solving for X 1 (x) and X 2 (x), the deflections of the two blocks along the x-axis. The solution of these two spatial displacements was obtained using the boundary conditions presented in equation (10), which describes the interaction of the two blocks with respect to each other and the clamping. Using the mentioned displacement profiles, X 1 (x) and X 2 (x), the resonance frequency, the strain, the stress-charges, the voltage, and the power were obtained according to equations ( 13)- (21).…”

“…The characteristic equation ( 6) is solved for the spatial composition (X 1,2 (x)), which gives the generic equation ( 9), including eight coefficients: A 1,2 , B 1,2 , C 1,2 , and D 1,2 . The coefficients were found using the boundary conditions for the system [46], shown in the set of equation (10).…”

“…Thanks to MEMS fabrication processes and the relatively high electromechanical coupling, different active piezoelectric materials have been integrated onto rigid silicon cantilevers; of those, one can cite sputtered aluminum nitride (AlN) [6][7][8], deposited thin film lead zirconate titanate (PZT) [9][10][11][12], screen-printed thick PZT [13,14], and thinned bulk-PZT [15,16]. Besides the silicon industry, the plastic and printed electronics industry is starting to establish itself.…”

Modeling and characterization of multilayeredd15mode piezoelectric energy harvesters in series and parallel connections

“…However, for most applications, different boundary conditions would be utilized. For instance, in experimental measurement, the supporting layers were usually clamped while the piezoelectric layers were glued to the supporting layers without clamping [16][17][18][19], which would lead to relatively large deviation of output electrical performances obtained from theoretical modeling and experimental measurement. Therefore, considering the different boundary conditions for piezoelectric and non-piezoelectric layers in the theoretical model is important, which would improve the accuracy of output performance prediction for piezoelectric energy harvesters.…”