THE SAW PROPERTIES OF SPUTTERED SiO_(2) ON X-112°Y LiTaO_(3)

摘要

The surface acoustic wave (SAW) propagation properties on the X-cut plate, 112°Y rotated, lithium tantalate (LiTaO_(3)) substrate with and without sputtered SiO_(2) film layers have been investigated using interdigital transducer electrode structures. Thicknesses of SiO_(2) of 500 nm and 1000 nm were sputter deposited on the X-112°Y LiTaO_(3) substrates. A series array of aluminum electrode patterns deposited on the film facilitated the excitation of a wide frequency band of harmonic waves up to 2.0 GHz, and permitted delineation of SAW velocity and propagation loss characteristics for several values of film-thickness to acoustic-wavelength (t/λ) ratio. A resonator pattern at the substrate/film interface, permitted the capacitance ratio (C_(m)/C_(o)), related to coupling factor, and the temperature coefficient of frequency (TCF) to be measured. A high velocity pseudo-SAW (HVPSAW) mode was observed with a velocity near 6300 m/s.