Mechanical Fracture of Piezoelectric Single Crystal Chip Resonator due to High Input Power

Noboru WAKATSUKI  Takatoshi OKUDA  

IEICE TRANSACTIONS on Electronics   Vol.E83-C   No.9   pp.1422-1426
Publication Date: 2000/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Current Electromechanical Devices and Their Materials with Recent Innovations)
piezoelectric single crystal,  chip resonator,  mechanical fracture,  lithium niobate,  lithium tantalate,  

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Using LiTaO3 and LiNbO3 single crystals, we wish to miniaturize a powerful ultrasonic vibrator. We studied the method of measuring mechanical fractures of resonators with good reproducibility and collected data on mechanical fractures of crystals due to high input electric power. Chip resonators with a 4 MHz and 8 MHz shear mode were selected for the test samples. The driving frequency was swept near the resonance frequency, the duration time was short enough to raise the resonant vibrations and the driving voltage increased in one-volt increments. The method is free from unstable temperature increases. Values of the fracture limit for the driving current were measured and transformed to mechanical vibration velocities. These showed a nearly normal distribution. It was a surprise that concavity in the crater was observed at the center of the 16 MHz LiNbO3 resonator due to high input power. It was confirmed that the elastic fracture limit was latently very high for LiNbO3 and LiTaO3 single crystals.