Aluminum nitride based piezoelectric harvesters

This work demonstrates the fabrication of simple of AlN-based piezoelectric energy harvesters (PEH), made of cantilevers with thin films prepared by ion beam-assisted deposition. The preferentially (001) orientated AlN thin films have exceptionally high piezoelectric coefficients of (7.33 ± 0.08) pC·$N^{-1}$. The fabrication of PEH was done using only three lithography steps, employing conventional silicon substrate with precise control of the cantilever and it’s mass thicknesses. The AlN deposition was done at a temperature of ≈ 330 °C which makes it compatible with complementary metal oxide semiconductor technology (CMOS). The PEH cantilever deflection and efficiency were characterized using both laser interferometry and a vibration shaker, respectively. This technology could become useful for future CMOS-based energy harvesters integrated on chip with circuits.