Electrostatic energy harvesting device with out-of-the-plane gap closing scheme

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 with a four wafer stack are batch fabricated and fully packaged at wafer scale. 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 1.1×1.3 cm². With an external load 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.