Lamb-wave high-frequency resonator

Abstract

To provide a Lamb-wave high-frequency resonator which obtains high frequency waves, has excellent frequency temperature characteristics and can reduce its manufacturing cost.The Lamb-wave high-frequency resonator 1 includes an interdigital IDT electrode 20 for exciting a Lamb wave on one main surface of a quartz substrate 10, the IDT electrode 20 is formed such that the cut angle of the quartz substrate 10 and the direction of propagation of the Lamb wave are expressed in Euler angles (0, [theta], 0), relation between thickness t of the quartz substrate 10 and the wavelength [lambda] is set within a range to be expressed as 0 H03H 9 / 145 H03H 9 / 25 H01L 41 / 09 H01L 41 / 18 17 15 2 2006 / 1 / 6 1801612 2006 / 7 / 12 100477514 2009 / 4 / 8 2009 / 4 / 8 2009 / 4 / 8 Seiko Epson Corp. Japan Tanaka Satoru li hui 11127 San You Patent Agency No.201 Entrance 1, Building 13, the East of Jinmenli, Haidian District, Beijing 100088 Japan 2005 / 1 / 7 JP2005-002111 Japan 2005 / 10 / 5 JP2005-292126

Description

technical field [0001] The present invention relates to a Lamb wave type high-frequency resonator, in particular to a Lamb wave type resonator with a quartz substrate and a propagation direction represented by Euler angles (0, θ, 0) and composed of IDT electrodes high frequency resonator. Background technique [0002] Conventionally, high-frequency resonators have been typified by surface acoustic wave elements using Rayleigh waves and SH waves, and Lamb wave-type resonators using Lamb waves. As their substrates, ST-cut quartz for Rayleigh waves and STW-cut quartz for SH waves are used, and AT-cut quartz is used for high-frequency resonators using Lamb waves. [0003] For example, a Rayleigh-wave type surface acoustic wave element in which IDT (Interdigital Transducer) electrodes are formed in the Z'-axis direction on the surface of a quartz substrate called ST-cut quartz is known (for example, refer to Non-Patent Document 1 ). [0004] In addition, as an SH-type surface ...

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Problems solved by technology

[0010] According to this Non-Patent Document 1, in the temperature range of -40°C to 90°C, the frequency-temperature variation is about 140ppm, and although a surface acoustic wave device exhibits good frequency-temperature characteristics, it is difficult for a resonator requiring high precision. can't say enough

In addition, the theoretical value of the phase velocity is about 3100m / s, and it is difficult to correspond to the high frequency band

[0011] Furthermore, according to Patent Document 1, the surface acoustic wave device is an end surface reflection type surface wave device using SH waves, and the frequency-temperature variation is 254 ppm in the temperature range of -40°C to 90°C. ST Cut Quartz Poor

In addition, using tantalum or tungsten, which is denser than aluminum, as an electrode material improves the frequency-temperature characteristics, but the resistance loss increases and the phase velocity decreases.

[0012] In addition, according to Patent Document 2, by using an AT-cut quartz substrate whose thickness is 5 wavelengths or less with respect to the wavelength of the elastic wave, the frequency-temperature characteristic is good and suitable for high frequency. However, according to Non-Patent Document 2, the secondary The temperature coefficient performance is the same as that of the aforementioned ST-cut quartz, and the frequency-temperature characteristic in the temperature range of -40°C to 90°C is about 320ppm, which is not superior to ST-cut quartz, and cannot be said to have met the requirements.

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