In this paper, we report on an electrostatic energy harvester with an out-of-the-plane gap closing scheme. Using advanced MEMS technology, energy harvesting devices formed by a four wafer stack are batch fabricated and fully packaged at wafer scale. A spin coated CYTOP polymer is used both as an electret material and an adhesive layer for low temperature wafer bonding. The overall size of the device is about 1.1 cm × 1.3 cm. At an external load resistance of 13.4 MΩ, a power output of 0.15 μW is achieved when vibration at an acceleration amplitude of 1 g (∼9.8 m/s2) is applied at a low frequency of 96 Hz. The frequency response of the device is also measured and a broader bandwidth is observed at higher acceleration amplitude.
Sensors and Actuators A: Physical, 2014, Vol 211, p. 131-137
CYTOP; Electrets; Energy harvesting; MEMS; Wireless sensor networks; Frequency response; Magnetic anisotropy; Acceleration amplitude; Adhesive layers; Electret materials; Electrostatic energies; Energy harvesting device; Low temperature wafer bonding; MEMS technology