METHOD FOR MANUFACTURING POTASSIUM NIOBATE SINGLE CRYSTAL THIN FILM, SURFACE ACOUSTIC WAVE DEVICE, FREQUENCY FILTER, FREQUENCY OSCILLATOR, ELECTRONIC CIRCUIT, AND ELECTRONIC EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To epitaxially grow high-quality KNbO3single crystal thin film on various single crystal substrates by enabling a crystal growth process of depositing single crystal from a liquid phase in atmosphere to be employed to a thin film manufacturing process using a vapor phase method under the reduced pressure by solving the problem wherein, in manufacture of potassium niobate thin film having an excellent electro-mechanical coupling coefficient, the saturated vapor pressure of K is extremely higher than that of Nb and therefore K is liable to evaporate and the composition of the manufactured thin film is deviated to an Nb excess side as compared to a starting composition and the manufactured thin film is inferior in the electro-mechanical coupling coefficient, and to provide a surface acoustic wave device which meets a trend toward higher frequencies and has high k2and with which the effect of miniaturizatio and power-saving are expected.

SOLUTION: The surface acoustic wave device having large electro-mechanical coupling coefficient is obtained by depositing raw materials of a composition from K2O:Nb2O5=50:50 up to K2O:Nb2O5=65:35 on a substrate held at the eutectic temperature of the potassium niobate and 3K2O-Nb2O5or above at high deposition speed and growing the potassium niobate thin film in the form of a single crystal free of the deviation in the composition from the liquid phase. The miniaturization of the frequency filter and the frequency oscillator and the power saving of the electronic circuit and the electronic equipment are realized by the surface acoustic wave device.

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