Fabrication and application of flexible AlN piezoelectric film

A fabrication method for high quality flexible aluminum nitride piezoelectric thin films based on micro-nano fabrication technology is reported in this paper. Molybdenum (Mo)/aluminum nitride (AlN)/aluminum (Al) structure was prepared on silicon(100) by sputtering. Then, deep-reactive ion etching technology was used to remove the silicon material used for support, then the Mo/AlN/Al flexible sandwich film was obtained. The full-width at half-maximum of the AlN film (002) peak before and after removal of silicon was only 1.47° and 1.49°, respectively. No obvious cracks in the film under bending conditions were observed with a scanning electron microscope. Capacitance–voltage (C–V) test results showed that the capacitance curve of the sandwich structure was consistent with that of the double-sided Schottky junction. The flexible piezoelectric film with an active area of 2 × 2 mm2 exhibited an average peak-to-peak generated voltage of 0.6 V in energy harvesting tests, which indicates that the method could be used to fabricate high quality flexible energy collectors based on AlN film. The preparation scheme in this paper is compatible with integrated circuit processes and simple to implement, which lays a foundation for the wide application of flexible piezoelectric devices.