A 1.3 Milliwatts Electrostatic Vibrational Energy Harvester with Minimal Reactive Power through Reduced Internal Stray Capacitances

This paper reports on a methodology to enhance the output power of vibrational MEMS energy harvesters by reducing the reactive power. An SOI wafer with a relatively thick BOX layer is used to reduce the internal stray capacitance, thereby reducing the reactive power. The active power is 2.4-fold improved by increasing the BOX layer from 1 μm to 3 μm, resulting in a power enhancement to 1.3 mW, without changing the device design or footprint.