title: Synthesis and surface acoustic wave properties of AlN films deposited on LiNbO3 substrates.
abstract: The c-axis-oriented aluminum nitride (AIN) films were deposited on z-cut lithium niobate (LiNbO3) substrates by reactive RF magnetron sputtering. The crystalline orientation of the AIN film determined by x-ray diffraction (XRD) was found to be dependent on the deposition conditions such as substrate temperature, N2 concentration, and sputtering pressure. Highly c-axis-oriented AIN films to fabricate the AIN/LiNbO3-based surface acoustic wave (SAW) devices were obtained under a sputtering pressure of 3.5 mTorr, N2 concentration of 60%, RF power of 165 W, and substrate temperature of 400 degrees C. A dense pebble-like surface texture of c-axis-oriented AIN film was obtained by scanning electron microscopy (SEM). The phase velocity and the electromechanical coupling coefficient (K2) of SAW were measured to be about 4200 m/s and 1.5%, respectively. The temperature coefficient of frequency (TCF) of SAW was calculated to be about -66 ppm/ degrees C.
mesh_terms: D000162:Acoustics / Q000295:instrumentation*; D017607:Aluminum Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray / Q000379:methods*; D004867:Equipment Design / Q000379:methods; D008422:Materials Testing / Q000379:methods*; D008872:Microwaves; D008962:Models, Theoretical; D009556:Niobium / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013379:Substrate Specificity; D013696:Temperature; D014159:Transducers
chemical_list: D017607:Aluminum Compounds; D010087:Oxides; D009556:Niobium; C091692:lithium niobate; C052045:aluminum nitride