Fabrication and characterization of vibration-driven AlN piezoelectric micropower generator compatible with complementary metal-oxide semiconductor process

Abstract

This article describes the aluminum nitride (AlN)-based piezoelectric microgenerator for scavenging energy from ambient vibration. To achieve the low resonance frequency and maximize power density, a parametric study has been carried out by analytical modeling and finite element analysis. The piezoelectric microgenerator consists of AlN piezoelectric thin film with molybdenum (Mo) electrodes and silicon (Si) proof mass. The AlN was deposited on silicon-on-insulator wafer which is used as an insulating layer to defend the leakage current. The Mo electrode provides the excellent c-axis crystal growth of AlN. The fabricated AlN piezoelectric microgenerator can generate up to 6.4 nW at a frequency of 389 Hz and acceleration of 1.0 g (1 g = 9.81 m/s²). In addition, the output voltage and power density are 22.6 mV_rms and 11.3 nW/mm³, respectively. The proposed generator is highly suitable for batch processing and has the possibility of harvesting energy from the ambient vibration.