US EPA

6937431 

Journal Article 

Thin-Film Piezoelectric Materials For a Better Energy Harvesting MEMS 

Wasa, K; Matsushima, T; Adachi, H; Kanno, I; Kotera, H; , 

2012 

Yes 

I E E E Journal of Microelectromechanical Systems
ISSN: 1057-7157 

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC 

PISCATAWAY 

451-457 

10.1109/JMEMS.2011.2181156 

WOS:000302535800025 

Ferroelectric PZT-based perovskite thin films are widely studied for fabrication of compact piezoelectric energy harvesting (EH) power microelectromechanical systems (MEMS) due to their large piezoelectric coefficients. Output energy of the piezoelectric EH power MEMS is chiefly governed by their energy conversion rate, k(2) and/or (e(2)/epsilon), where e and e denote their piezoelectric coefficient and dielectric constant. The values of (e(2)/epsilon) are considered as figures of merit (FOM) for the piezoelectric EH power MEMS. At present nonferroelectric AlN thin films are considered as a candidate for a better piezoelectric EH power MEMS due to their high FOM values. These PZT-based thin films are mostly polycrystalline thin films of binary perovskite compounds, Pb(Zr, Ti)O-3 (PZT). We have proposed single crystal thin films of PZT-based ternary perovskite compounds, Pb(Mn, Nb)O-3-PZT (PMnN-PZT), instead of the binary perovskite PZT. The single crystal PMnN-PZT thin films have been successively fabricated by rf-magnetron sputtering. It is found that the FOM values of single c-domain/single crystal PMnN-PZT thin films are one order of magnitude higher than those of AlN thin films. This suggests output powers of the PMnN-PZT thin-film EH power MEMS are one order of magnitude higher than those of the AlN thin-film EH power MEMS.