Standardized evaluation of chemical compositions of LiTaO3 single crystals for SAW devices using the LFB ultrasonic material characterization system.

The line-focus-beam ultrasonic material characterization (LFB-UMC) system is applied to compare and evaluate tolerances provided independently for the Curie temperature T(C) and lattice constant a to evaluate commercial LiTaO3 single crystals by measuring the Rayleigh-type leaky surface acoustic wave (LSAW) velocities V(LSAW). The relationships between V(LSAW), and T(C) and a measured by individual manufacturers were obtained experimentally using 42 degrees Y X-LiTaO3 wafers as specimens from three crystal manufacturers. In addition, the relationship between V(LSAW) and SH-type SAW velocities V(SAW) that are actually used for the SAW device wafers was obtained through calculations, using the chemical composition dependences of the acoustical physical constants for LiTaO3 crystals reported previously.