5-GHz-band surface acoustic wave (SAW) filters for mobile communication were fabricated on atomically-flat-surface (0001)aluminum nitride/(0001)sapphire (AlN/Al2O3) combination. The SAW devices were fabricated using electron beam lithography and lift-off method. Atomically-flat-surface AlN films were used to reduce SAW propagation loss. Center frequency of the fabricated SAW filter was 5.18 GHz. SAW velocity was 5688 m/s at normalized thickness by wave number (kH) of 9.9. Effective coupling coefficient was 0.1 % and temperature-coefficient of delay was 9ppm/°C at kH of 5.9. SAW propagation loss was 0.0053 dB at 5.18 GHz. The atomically-flat-surface (0001)AlN/(0001)Al2O3 combination is promised to be used for 5-GHz-band SAW filter for the application to mobile communication.
ASJC Scopus subject areas
- Acoustics and Ultrasonics