Title :
SAW velocity measurement of crystals and thin films by the phase velocity scanning of interference fringes
Author :
Yamanaka, Kazushi ; Nagata, Yoshihiko ; Nakano, Shizuka ; Koda, Toshio ; Nishino, Hideo ; Tsukahara, Yusuke ; Cho, Hideo ; Inaba, Masatoshi ; Satoh, Akinobu
Author_Institution :
Mechanical Eng. Lab., Ibaraki, Japan
fDate :
5/1/1995 12:00:00 AM
Abstract :
We present principle and application of a novel noncontact velocity measurement of surface acoustic waves (SAW) on crystals and thin films using laser interference fringes scanned at the phase velocity of SAW. The scanning interference fringes (SIF) are produced by intersecting two laser beams with a frequency difference. The SAW velocity within the laser beam spot is measured as the ratio of observed SAW frequency and predetermined wave number of the SIF. The frequency measurement can be quite precise because of a large number of generated SAW carriers and amplitude enhancement effect. The SAW velocity measurement is free from the water loading effect accompanying the leaky SAW measurements. This principle was successfully applied to evaluate Si/sub 3/N/sub 4/ and SiO/sub 2/ films deposited on Si [001] surface.<>
Keywords :
acoustic wave velocity measurement; acousto-optical effects; light interferometry; surface acoustic waves; thin films; SAW velocity measurement; Si; Si [001] surface; Si/sub 3/N/sub 4/; SiO/sub 2/; crystals; frequency measurement; laser beams; noncontact measurement; phase velocity; scanning interference fringes; surface acoustic waves; thin films; Acoustic beams; Acoustic waves; Crystals; Frequency measurement; Interference; Laser beams; Surface acoustic waves; Surface emitting lasers; Transistors; Velocity measurement;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
