Micro harvester using isotropic charging of electrets deposited on vertical sidewalls for conversion of 3D vibrational energy

The design and fabrication process of an integrated micro energy harvester capable of harvesting electrical energy from low amplitude mechanical vibrations is presented. A specific feature of the presented energy harvester design is its capability to harvest vibrational energy from different directions (3D). This is done through an innovative approach of electrets placed on vertical sidewalls, allowing miniaturization of 3D capacitive energy harvester fabrication on monolithic CMOS substrates. A new simple electret charging method using ionic hair-dryers is used. The charging performance of SiO2 and CYTOP electrets are characterized for electrets in horizontal arrangement and electrets deposited on vertical sidewalls.