The line-focus-beam ultrasonic material characterization (LFB-UMC) system is applied to a standardized comparison and evaluation of the Curie temperatures, TC, exclusively used in evaluating the chemical compositions of commercial LiTaO3 crystals by measuring the velocities of Rayleigh-type leaky surface acoustic waves (LSAWs), VLSAW. We measured VLSAW and TC(standardized) under the same TC measurement conditions for 36°Y X-LiTaO3 single-crystal wafers produced by four manufacturers and related the results to the TC(individual) measured by the individual manufacturers. The relationships between VLSAW and TC(individual) varied from one company to another, and a single straight line of the proportional relationship between VLSAW and TC(standardized) was obtained for all wafers regardless of the manufacturer. These experimental results clarify that the problem associated with TC measurements lies in the measurement conditions and the absolute accuracy of the measurement instruments. Measurements of the center frequencies of the actual SH-type surface acoustic waves (SAW) filter devices fabricated also are compared with VLSAW measurements. A method of calibrating TC using this ultrasonic system is proposed to establish standardized specifications of SAW-device crystal wafers.
|Number of pages||9|
|Journal||IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control|
|Publication status||Published - 2003 May|
ASJC Scopus subject areas
- Acoustics and Ultrasonics
- Electrical and Electronic Engineering