Surface acoustic wave resonator and surface acoustic wave oscillator

Abstract

The invention provides a surface acoustic wave resonator and a surface acoustic wave oscillator with a good frequency temperature characteristic. A SAW resonator (10) which, using a quartz crystal substrate (30) with Euler angles (117 DEG<=theta<=142 DEG, and 42.79 DEG<=Psi<=49.57 DEG, includes an IDT (10) which excites a stop band upper end mode SAW, and grooves (32) hollowed out of the substrate positioned between electrode fingers (18) configuring the IDT, wherein, when the wavelength of the SAW is [lambda] and the depth of the inter-electrode finger grooves is G, [lambda] and G satisfy the relationship of 0.01[lambda]<=G and wherein, when the line occupation rate of the IDT is [eta], the groove (32) depth G and line occupation rate [eta] satisfy the relationships of - 2.5xG / Lambda+0.675<=-2.5xG / Lambda+0.775.

Description

technical field The present invention relates to a surface acoustic wave resonator and a surface acoustic wave resonator equipped with the surface acoustic wave resonator, and more particularly to a surface acoustic wave resonator of the type provided with grooves on the surface of a substrate and a surface acoustic wave resonator equipped with the surface acoustic wave resonator. Background technique In a surface acoustic wave (SAW: surface acoustic wave) device (such as a SAW resonator), the stopband (stopband) of the SAW, the chamfer of the quartz substrate, and the formation method of the IDT (interdigital transducer: interdigital transducer) affect the frequency. Changes in temperature characteristics have a large influence. For example, Patent Document 1 discloses a structure for exciting the upper mode and the lower mode of the stop band of a SAW, and the standing wave distributions of the upper mode and the lower mode of the stop band of the SAW. In addition, Pate...

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Problems solved by technology

However, the present applicant has found in experiments that when the film thickness of the electrode is increased, the environmental resistance characteristics such as aging characteristics and temperature shock resistance characteristics deteriorate.

In addition, when the main purpose is to improve the frequency-temperature characteristics, it is necessary to increase the thickness of the electrode film as described above, and the accompanying deterioration of the aging characteristics and temperature shock resistance characteristics cannot be avoided.

This also applies to the Q value phase, so it is difficult to achieve high Q without increasing the electrode film thickness

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