Murata Manufacturing Co., Ltd.

Takeshi Nakao

Michio Kadota

Kenji Nishiyama

Masakazu Mimura

Toshimaro Yoneda

Koji Fujimoto

Yasuharu Nakai

Shunsuke Kido

Hideya Horiuchi

Yoshihiro Koshido

Junya Ago

Yasuhiro Kuratani

Takuo Hada

Makoto Tose

Masatoshi Nakagawa

Takashi Yamane

Seiji Kai

Hisashi Yamazaki

Osamu Nakagawara

Hajime Kando

Tetsuya Kimura

Hideki Iwamoto

Norio Taniguchi

Eiichi Takata

Shou Nagatomo

Daisuke Tamazaki

Daisuke Yamamoto

Tomohisa Komura

Kenji Nishimaya

An acoustic wave device includes a support, a piezoelectric layer on the support, a functional electrode at the piezoelectric layer, a frame-shaped support frame on the piezoelectric layer and surrounding the functional electrode in plan view in a stacking direction of the support and the piezoelectric layer, and a lid covering an opening of the support frame, wherein the support includes a first cavity overlapping at least a portion of the functional electrode in the plan view, a second cavity defined by the piezoelectric layer, the support frame, and the lid between the piezoelectric layer and the lid, the piezoelectric layer includes a through hole communicating with the first and second cavities, and a gas is provided in the first and second cavities.

Acoustic wave device

An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support, a functional electrode at the piezoelectric layer, a frame-shaped support frame on the piezoelectric layer and surrounding the functional electrode in a plan view in a stacking direction of the support and the piezoelectric layer. A lid covering an opening of the support frame, wherein the support includes a first cavity at a position overlapping at least a portion of the functional electrode in the plan view, a second cavity defined by the piezoelectric layer, the support frame, and the lid between the piezoelectric layer and the lid. The piezoelectric layer includes a through hole communicating with the first and second cavities, and the first and second cavities are under vacuum.

An acoustic wave device includes a support substrate, a piezoelectric film, a functional electrode, and a support. The support substrate includes a cavity. The piezoelectric film is provided on the support substrate to cover the cavity. The functional electrode is provided on the piezoelectric film to overlap the cavity when viewed in a plan view. The support is in the cavity of the support substrate to support the piezoelectric film. The functional electrode includes electrodes arranged in a direction crossing the thickness direction of the piezoelectric film. The electrodes include a first electrode and a second electrode. The first electrode and the second electrode oppose each other in a direction crossing the thickness direction of the piezoelectric film and are connected to different potentials. Adjacent ones of the electrodes overlap each other in a direction orthogonal to a longitudinal direction of the first electrode.

A boundary acoustic wave device includes an LiTaOpiezoelectric substrate, a first dielectric medium layer disposed on the piezoelectric substrate, a second dielectric medium layer disposed on the first medium layer and having a sound velocity different from the first medium layer, and an interdigital electrode disposed at the boundary between the piezoelectric substrate and the first medium layer. The sound velocity of the first medium layer is less than the sound velocity of LiTaO. The sound velocity of the second medium layer is greater than the sound velocity of LiTaO. The inequality (h/&#x3bb;)&#xd7;a&#x2266;0.05 is satisfied, where H is the thickness of the first medium layer, h is the thickness of the interdigital electrode, &#x3bb; is the period of electrode fingers of the interdigital electrode, and a is the ratio of the density of a metal of the interdigital electrode to the density of Au.

Boundary acoustic wave device

A surface acoustic wave device includes a piezoelectric substrate, at least one interdigital transducer (IDT) electrode provided on the piezoelectric substrate, and an insulator layer to improve a temperature characteristic arranged so as to cover the IDT electrode. When a surface of the insulator layer is classified into a first surface region under which the IDT electrode is positioned and a second surface region under which no IDT electrode is positioned, the surface of the insulator layer in at least one portion of the second surface region is higher than the surface of the insulator layer from the piezoelectric substrate in at least one portion of the first surface region by at least about 0.001&#x3bb;, where the wavelength of an acoustic wave is &#x3bb;.

Acoustic wave device and method for fabricating the same

A method for fabricating an acoustic wave device includes the steps of forming an insulating material layer on a piezoelectric substrate, forming a patterned photoresist on the insulating material layer, patterning the insulating material layer, and forming a piezoelectric-substrate exposed depression corresponding to a region where an interdigital transducer electrode is to be formed on a first insulator layer composed of the insulating material layer, depositing a metallic material on the piezoelectric substrate to form the interdigital transducer electrode in the piezoelectric-substrate exposed depression such that the overall interdigital transducer electrode is thinner than the first insulator layer and coating the photoresist with a metallic material, removing the photoresist and the metallic material on the photoresist, and depositing a second insulator layer so as to cover the interdigital transducer electrode and the first insulator layer.

Method for fabricating acoustic wave device

A boundary acoustic wave device includes a piezoelectric substrate made of single-crystalline LiTaO, a first medium layer disposed on the piezoelectric substrate and made of a dielectric, a second medium layer disposed on the first medium layer and made of a dielectric having a sound velocity different from that of the first medium layer, and at least one interdigital electrode disposed at the boundary between the piezoelectric substrate and the first medium layer. The sound velocity of the first medium layer is less than the sound velocity of LiTaO. The sound velocity of the second medium layer is greater than the sound velocity of LiTaO. The inequality (h/&#x3bb;)&#xd7;a&#x2266;0.05 is satisfied, where H is the thickness of the first medium layer, h is the thickness of the interdigital electrode, &#x3bb; is the period of electrode fingers of the interdigital electrode, and a is the ratio of the density of a metal of the interdigital electrode to the density of Au.

A surface acoustic wave device prevents a decrease in yield and a decrease in reliability, such as an impulse withstand voltage, and achieves good frequency characteristics, even when using higher frequencies. The surface acoustic wave device includes an IDT electrode disposed on a piezoelectric substrate, and a first insulating film and at least one second insulating film disposed on the IDT electrode, and utilizes a higher-order mode of an SH wave, in which the acoustic velocity of a surface acoustic wave in the first insulating film located closer to the IDT electrode than the insulating film at an outermost surface is higher than the acoustic velocity of a surface acoustic wave in the second insulating film located at the outermost surface.

Surface acoustic wave device

An acoustic wave element includes an IDT electrode in contact with a piezoelectric material and including a plurality of electrode fingers, which include first and second electrode fingers that adjoin each other in an acoustic wave propagation direction and that connect to different potentials and a first dummy electrode finger facing the first electrode finger via a gap located on an outer side in an electrode finger length direction of the first electrode finger. At an area near the gap, first protrusions are provided in at least one of the first electrode finger and the first dummy electrode finger, the first protrusion protruding in the acoustic wave propagation direction from at least one of side edges of the at least one of the first electrode finger and the first dummy electrode finger. The acoustic wave element has greatly improved resonance characteristics of a resonance frequency and prevents short-circuit failure between electrode fingers and degradation in insulation properties.

Acoustic wave element having an electrode finger with a protrusion

A surface acoustic wave device includes a LiTaOsubstrate, and an IDT having a high reflection coefficient, which has a relatively high electromechanical coupling coefficient k, and which can obtain superior resonance characteristics and/or filter characteristics. In a surface acoustic wave device in which a plurality of grooves is provided in an upper surface of a LiTaOsubstrate and an IDT having a plurality of electrode fingers made of a metal filled in the plurality of grooves, the following equation is satisfied: (&#x3c1;&#xd7;C)&#x3e;1.95&#xd7;10, where &#x3c1; represents the density of the metal defining the IDT, and Crepresents the stiffness thereof.

Surface acoustic wave device including an IDT defined by a metal filled in grooves in a piezoelectric substrate

In an acoustic wave resonator, an IDT electrode is provided on a piezoelectric substrate. The IDT electrode is apodization-weighted such that a plurality of maximum values of cross widths are provided in acoustic wave propagation directions. Alternatively, in apodization weighting, weighting is applied such that at least one of a pair of envelopes located at outer side portions of the IDT electrode in directions substantially perpendicular to acoustic wave propagation directions includes a plurality of angled envelope portions angled from a central portion of the IDT electrode toward an outer side portion of the IDT electrode in a direction substantially perpendicular to the acoustic wave propagation directions.

Acoustic wave resonator

A surface acoustic wave device has high power withstanding performance and is able to effectively suppress an undesirable spurious response. The surface acoustic wave device includes an LiNbOsubstrate having Euler angles (0&#xb0;&#xb1;5&#xb0;, &#x3b8;&#xb1;5&#xb0;, 0&#xb0;&#xb1;10&#xb0;), an electrode that is disposed on the LiNbOsubstrate and that has an IDT electrode made mainly from Cu, a first silicon oxide film that is disposed in an area other than an area in which the electrode is disposed to have a thickness equal to that of the electrode, and a second silicon oxide film that is disposed so as to cover the electrode and the first silicon oxide film, wherein the surface acoustic wave device utilizes an SH wave, wherein a duty D of the IDT electrode is less than or equal to about 0.49, and &#x3b8; of the Euler angles (0&#xb0;&#xb1;5&#xb0;, &#x3b8;&#xb1;5&#xb0;, 0&#xb0;&#xb1;10&#xb0;) is set to fall within a range that satisfies the following inequality:&#x2212;10&#xd7;+92.5&#x2212;100&#xd7;&#x2266;&#x3b8;&#x2266;37.5&#xd7;&#x2212;57.75&#xd7;+104.075+5710&#xd7;&#x2212;1105.7&#xd7;45.729

A method of manufacturing a surface acoustic wave device having a high electromechanical coefficient and reflection coefficient, and also having an improved frequency-temperature characteristic is achieved by forming a SiOfilm on an IDT so as to prevent cracking from occurring on a surface of the SiOfilm so that desired properties can be reliably obtained. The surface acoustic wave device includes at least one IDT, which is composed of a metal or an alloy having a density higher than that of Al and is formed on a 25&#xb0; to 55&#xb0; rotation-Y plate X propagation LiTaOsubstrate, and a SiOfilm disposed on the LiTaOsubstrate so as to cover the at least one IDT for improving the frequency-temperature characteristic.

Method for manufacturing a surface acoustic wave device

A surface acoustic wave device has a duty that is greater than about 0.5, attenuation outside the pass band is increased, and an undesirable spurious response is effectively suppressed. The surface acoustic wave device includes an LiNbOsubstrate having Euler angles (0&#xb0;&#xb1;5&#xb0;, &#x3b8;&#xb1;5&#xb0;, 0&#xb0;&#xb1;10&#xb0;), an electrode that is provided on the LiNbOsubstrate and that includes an IDT electrode primarily made of Cu, a first silicon oxide film that is provided in an area other than an area in which the electrode is arranged so as to have a thickness substantially equal to that of the electrode, and a second silicon oxide film that is arranged so as to cover the electrode and the first silicon oxide film, wherein the surface acoustic wave device utilizes an SH wave, wherein a duty D of the IDT electrodeis at least about 0.52, and &#x3b8; of the Euler angles (0&#xb0;&#xb1;5, &#x3b8;+5&#xb0;, 0&#xb0;&#xb1;10&#xb0;) is set so as to fall within a range that satisfies the following Inequality (1A) or (1B):(1) When 0.52&#x2266;0.6, &#x2212;10+92.5&#x2212;100&#x2266;&#x3b8;&#x2266;37.5&#x2212;57.75+104.075+5710&#x2212;1105.7+45.729 &#x2003;&#x2003;Inequality (1A)(2) When&#x3e;0.6, 86.5&#x2212;100&#x2266;&#x3b8;&#x2266;37.5&#xd7;D&#x2212;57.75+104.075+5710&#x2212;1105.7+45.729&#x2003;&#x2003;Inequality (1B)

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Nagaokakyo, Japan

Takeshi Nakao