Calibration of Curie Temperatures for LiTaO[sub 3] Single Crystals by the LFB Ultrasonic Material Characterization System.

Autor: Jun-ichi Kushibiki, Ohashi, Yuji, Mishima, Naoyuki
Předmět:
Zdroj: IEEE Transactions on Ultrasonics Ferroelectrics & Frequency Control; May2003, Vol. 50 Issue 5, p544, 9p, 3 Black and White Photographs, 6 Charts, 4 Graphs
Abstrakt: The line-focus-beam ultrasonic material characterization (LFB-UMC) system is applied to a standardized comparison and evaluation of the Curie temperatures, T[sub C], exclusively used in evaluating the chemical compositions of commercial LiTaO[sub 3] crystals by measuring the velocities of Rayleigh-type leaky surface acoustic waves (LSAWs), V[sub LSAW]. We measured V[sub LSAW] and T[sub C](standardized) under the same T[sub C] measurement conditions for 36°YX-LiTaO[sub 3] single-crystal wafers produced by four manufacturers and related the results to the T[sub C](individual) measured by the individual manufacturers. The relationships between V[sub LSAW] and T[sub C](individual) varied from one company to another, and a single straight line of the proportional relationship between V[sub LSAW] and T[sub C](standardized) was obtained for all wafers regardless of the manufacturer. These experimental results clarify that the problem associated with T[sub C] 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 V[sub LSAW] measurements. A method of calibrating T[sub C] using this ultrasonic system is proposed to establish standardized specifications of SAW-device crystal wafers. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index