CMOS-MEMS PIEZOELECTRIC ENERGY HARVESTING SYSTEM

This paper reports a low-cost, high-sensitivity CMOS-MEMS piezoelectric energy
harvester with large proof mass. Piezoelectric has known to be the best in harvesting
ambient vibration energy. Its simple theory to produce voltage with stress and
vibration has come to many optimization researches to produce the best structure
with low natural frequency and high yield strength. Four common materials have
been compared to see the performance of generating the voltage output. Zinc Oxide,
ZnO thin film was utilized as the best piezoelectric material and device was designed
using the infamous cantilevered-beam structure which known as the best structure to
produce high sensitivity of vibration and has the highest stress effect at the beam tip
attached to the stator comb or fixed end. This structure is indeed compatible with
CMOS-MEMS fabrication. The structure has been designed and simulated. The
device has a sensitivity of I 13.4 J!VIg and the structure has been carefully optimized
to avoid structured damage due to undesired mode by incorporating the parallel beam
to the cantilever-based structure.