Acoustic Wave Properties of (100) AlN Films

Abstract

AlN films have been widely investigated for the application in surface acoustic wave (SAW) and films bulk acoustic wave (FBAW) devices. (100) AlN films have been deposited, but there is few research to study their acoustic properties. Different orientation piezoelectric films will form different acoustic properties. Bulk acoustic wave (BAW) and SAW properties of (100) AlN films were theoretically analyzed in this research. As regards the BAW properties, (100) AlN films can excite a pure shear mode (velocity=5867 m/s, K2=2.45%) and exhibited a great potential for FBAR liquid biosensors. As regards the Rayleigh SAW modes of (100) AlN films on diamond, especial for mode 1, the phase velocity is 10474 m/s and the K2 is 2.31 % at the films thickness ratio (h/l) is 0.3. (100) AlN films on diamond also can excite high velocity shear horizontal (SH) SAW modes. Especial for mode 0, the K2 curve shows a maximum value (1.27%) at h/l=0.28 and the velocity is 7496 m/s. Those research results provide an important theoretical basis for further application on FBAW and SAW devices.