AlN-based piezoelectric micropower generator for low ambient vibration energy harvesting

In this paper a resonant micropower generator based on the transverse piezoelectric effect is presented. The generator consists of a large silicon mass attached to an polysilicon cantilever covered with an AlN thinfilm as piezoelectric material. To maximize the power density of the generator, a parametric study by means of analytical modeling and FEM simulation has been performed. Different optimized generators with resonance frequencies in the range from 100 Hz up to 1 kHz have been designed and fabricated, using dedicated MEMS technology processes. First unpackaged prototypes showed a quality factor of about 500 under atmospheric pressure and were able to generate an electrical output power of up to 1.9 W at an external acceleration of 1.6 m/s 2.