Design and Fabrication Issues of a Silicon-Based Vibration Powered Electric Energy Generator Using Parallel Plate and In-Plane Mechanism

This paper focuses on the design and fabrication issues of a silicon-based, vibration powered, electric energy generator. Its architecture is based on the parallel plate configuration. It uses electrostatic damping of variable MEMS capacitor as the energy converting mechanism. Variable capacitance is achieved by in-plane movement of the top electrode. Hence capacitance variation is achieved by means of change in overlap area. The device is composed of a movable silicon proof mass with patterned electrodes on the underside, anodically bonded to a glass wafer with electrodes on top. High capacitance value can be achieved thanks to a low cost silicon-glass technology. FEM simulations along with the mechanical characterization have shown that 1.8 muW can be harvested for a 1 cm² device at the mechanical resonance frequency of 300 Hz and starting voltage of 5 V