Fabrication of micro piezoelectric energy harvester using eutectic bonding and polishing technology

This paper presents an energy harvester which operates at less than 1 kHz and consists of a micro siliconlead zirconate titanate (Si-PZT) cantilever and a nickel mass block on the cantilever. The energy harvester is a device that can convert the ambient mechanical vibration into electrical energy employing the piezoelectric effect. The micro piezo cantilever structure was fabricated by eutectic bonding using gold thin film as a bonding layer. A PZT mechanical polishing process was used to thin the bulk PZT. The thinnest PZT film obtained was 8 m. A nickel mass block (2 mm2 mm0.6 mm) was fabricated using micro electroforming process. By optimizing the bonding and polishing processes, the thickness of fabricated Si-PZT cantilever was about 71 m, and the thicknesses of the silicon beam and the PZT beam were about 47 m and 24 m, respectively. The results showed that the AC output voltage of the micro energy harvester was around 958 mV at the resonant frequency of 950 Hz and the acceleration of 1.0g.