Fabrication of Flexible Surface Acoustic Wave Devices Based on Aluminium Nitride

In this paper, surface acoustic wave devices were fabricated using aluminum nitride (AlN) film as piezoelectric layer, molybdenum (Mo) film as bottom electrode, and polyimide (PI) film as flexible substrate. The crystalline quality of Mo and AlN films was characterized by X-ray Diffraction (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM). Furthermore, the interdigital transducer (IDT) was fabricated by Ultraviolet Exposure and Electron Beam Exposure, and the resulting SAW device structure was IDTs/AlN/Mo/PI, the center frequency reaches GHz. After bending 100 times, the center frequency can still be kept at GHz, this shows that the flexible surface acoustic wave device shows better performance.