Murata Manufacturing Co., Ltd.

Yasumasa Taniguchi

Katsuya Daimon

Masakazu Mimura

Hideki Iwamoto

Takashi Yamane

Tsutomu Takai

Masashi Omura

Taku Kikuchi

Norihiko Nakahashi

Munehisa Watanabe

Akira Michigami

Koji Yamamoto

Takashi Miyake

Masato Araki

Daisuke Tamazaki

Takuma Kuzushita

Daisuke Fukuda

Takuro Okada

An acoustic wave device includes an IDT electrode and reflector electrodes on or above a piezoelectric substrate. A region in which first and second electrode fingers of the IDT electrode overlap each other in an acoustic wave propagation direction defines an intersection region. The intersection region includes a center region and first and second edge regions on both sides of the center region. Dielectric films extend from the first and second edge regions to outer side regions in the acoustic wave propagation direction of the reflector electrodes via the reflector electrodes.

Acoustic wave device

An acoustic wave device includes an IDT electrode on a piezoelectric layer. The IDT electrode includes first and second electrode fingers made of an alloy film including Al and at least one of Cu, Mg, Ag, or Nd, and an overlap region in which the first and second electrode fingers overlap when viewed in the direction of propagation of acoustic waves. The overlap region includes a central region and first and second edge regions outside the central region on opposite sides in the direction in which the first and second electrode fingers extend. In at least one of the first and second electrode fingers, a concentration of the at least one of Cu, Mg, Ag, or Nd in at least a portion of the first and second edge regions is higher than that in the central region.

Acoustic wave device with electrode fingers made of an alloy

A multiplexer includes a common terminal, first and second transmit filters, and a first receive filter connected to the common terminal and each including resonators, a relationship Tx1<Rx1<Tx2is satisfied, where Tx1, Tx2, and Rx1denote center frequencies of pass bands Tx1, Tx2, and Tx3 of the first and second transmit filters and the first receive filter, respectively, a resonator closest to the common terminal in the first receive filter is a series arm resonator, and a pitch ratio denoted by pS1 (Rx1)/p(Tx2) is more than about 1 and less than or equal to about 1.035, where p(Tx2) denotes an electrode finger pitch of an IDT electrode in a resonator closest to the common terminal in the second transmit filter and pS1 (Rx1) denotes an electrode finger pitch of an IDT electrode of the series arm resonator closest to the common terminal in the first receive filter.

Multiplexer

An acoustic wave filter includes acoustic wave resonators including a piezoelectric substrate and an IDT electrode including first and second electrode fingers. An intersecting region of the first and second electrode fingers includes a central region and first and second edge regions on outer side portions of the central region. An acoustic velocity in the first and second edge regions is lower than that in the central region, and the acoustic wave resonators include a first acoustic wave resonator with a width in the first and second edge regions larger than a width in the central region, and a second acoustic wave resonator including at least one of an acoustic velocity reducing film and an acoustic velocity increasing film in the central region, such that an acoustic velocity in the first and second edge regions is lower than acoustic velocity in the center region.

Acoustic wave filter

An acoustic wave device includes a piezoelectric layer, first and second upper electrodes, first and second lower electrodes, and first and second acoustic reflection films. In plan view, first and second resonator portions are respectively defined by portions where the first upper electrode and the first lower electrode overlap and where the second upper electrode and the second lower electrode overlap. The first and second acoustic reflection films respectively include first and second metal layers. First and second overlapping portions are respectively defined by portions where only the first upper electrode overlaps with the first metal layer and where only the second upper electrode overlaps with the second metal layer. An area of the first resonator portion is smaller than an area of the second resonator portion and an area of the first overlapping portion is larger than an area of the second overlapping portion.

An acoustic wave device includes a silicon substrate, a piezoelectric layer, and an IDT electrode. Each of the silicon substrate and the piezoelectric layer includes first and second opposed main surfaces. The IDT electrode is on the first main surface of the piezoelectric layer, and includes first and second electrode fingers. When a wavelength of an acoustic wave determined by an electrode finger pitch of the IDT electrode is denoted as λ, a distance between the first main surface of the silicon substrate and the second main surface of the piezoelectric layer in a thickness direction of the silicon substrate is less than about 0.84λ. The first main surface of the silicon substrate is rougher than the first main surface of the piezoelectric layer.

An acoustic wave device includes a piezoelectric substrate, a first interdigital transducer (IDT) electrode, reflectors on both sides of the first IDT electrode in a propagation direction of an acoustic wave, and a second IDT electrode facing the first IDT electrode with a reflector interposed therebetween. The first and second IDT electrodes include first and second intersecting areas in which electrode fingers overlap in the propagation direction. The first and second intersecting areas overlap in the propagation direction. A third busbar of the second IDT electrode is coupled to a first busbar of the first IDT electrode. A fourth busbar of the second IDT electrode is coupled to a ground potential. A resonant frequency of the second IDT electrode is in a frequency band of an interference wave signal.

Acoustic wave device, filter device, and multiplexer

An acoustic wave device includes a piezoelectric body including first and second main surfaces facing each other, an IDT electrode provided on the first main surface of the piezoelectric body and including electrode fingers, a high acoustic velocity member on the second main surface side of the piezoelectric body, in which an acoustic velocity of a propagating bulk wave is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric body, and a first dielectric film provided on an upper surface of the electrode fingers, in which a portion where a dielectric is not present is provided between the electrode fingers of the IDT electrode.

In an acoustic wave device, an IDT electrode is located on a piezoelectric layer. A high-acoustic-velocity member is positioned on an opposite side of the piezoelectric layer from the IDT electrode. An acoustic velocity of a bulk wave propagating through the high-acoustic-velocity member is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric layer. A low-acoustic-velocity film is provided between the high-acoustic-velocity member and the piezoelectric layer. An acoustic velocity of a bulk wave propagating through the low-acoustic-velocity film is lower than the acoustic velocity of the bulk wave propagating through the piezoelectric layer. A dielectric film is located on the piezoelectric layer so as to cover the IDT electrode. In the acoustic wave device, a Young's modulus of the dielectric film is larger than a Young's modulus of the low-acoustic-velocity film.

An acoustic wave device includes a piezoelectric substrate and an IDT electrode on the piezoelectric substrate. The IDT electrode includes first and second electrode fingers. When the propagation direction of acoustic waves is a first direction and the direction orthogonal or substantially orthogonal to the first direction is a second direction, an intersecting region of the IDT electrode includes a central region located toward the middle in the second direction and first and second edge regions on both sides in the second direction of the central region. The first and second electrode fingers include epitaxially grown oriented films in the central region and portions that do not include the oriented films in the first and second edge regions.

In an acoustic wave device, an interdigital transducer electrode is disposed on a piezoelectric substrate with a reverse velocity surface having an elliptic shape, and a dielectric film is disposed to cover the interdigital transducer electrode. Assuming an electrode density (%) of the interdigital transducer electrode to be y (%) and a wavelength-normalized film thickness 100h/&#x3bb; (%) of the interdigital transducer electrode to be x (%), the wavelength-normalized film thickness x of the interdigital transducer electrode takes a value not less than x satisfying y=0.3452x&#x2212;6.0964x+36.262 depending on the electrode density of the interdigital transducer electrode.

An acoustic wave device includes a support substrate having a central region and a surrounding region located around the central region, a silicon oxide film that is located in the central region directly or indirectly and that has a side surface, a piezoelectric layer that is provided on the silicon oxide film and that has a first principal surface and a second principal surface, an excitation electrode provided on at least one of the first principal surface and the second principal surface, a cover film provided to cover the entire side surface of the silicon oxide film, a resin layer that is provided in the surrounding region and that is provided to cover the side surface of the silicon oxide film from above the cover film, and a wiring electrode that is electrically connected to the excitation electrode and that extends from the piezoelectric layer to the resin layer.

An elastic wave device includes a piezoelectric material layer, an IDT electrode on the piezoelectric material layer, and a dielectric film covering the IDT electrode. The IDT electrode includes a first electrode layer and a second electrode layer laminated on the first electrode layer. Each of wavelength normalized film thicknesses of the first and second electrode layers is equal to or greater than about 1.25%, and is normalized using a wave length defined by the electrode finger pitch of the IDT electrode. The second electrode layer has a density lower than that of the first electrode layer. The side of the second electrode layer is inclined with respect to the thickness direction of the IDT electrode.

Elastic wave device, radio-frequency front-end circuit, and communication device

An elastic wave device includes, on an elastic wave element substrate, an IDT electrode including electrode fingers, and reflectors. At least one electrode finger of each of the reflectors include a portion having a relatively large thickness in a longitudinal direction and a portion having a relatively small thickness in the longitudinal direction. The portion having the relatively large thickness each reflector is thicker than a thickness of the electrode fingers of the IDT electrode.

Elastic wave device, high-frequency front-end circuit, and communication device

An elastic wave device includes an IDT electrode provided on a piezoelectric substrate and including a first end region including one end of the IDT electrode in an elastic wave propagation direction, a second end region including the other end of the IDT electrode in the elastic wave propagation direction, and an inner region that is located farther toward an inside than the first and second end regions in the elastic wave propagation direction, includes first and second high-acoustic-velocity regions, and a center region and first and second low-acoustic-velocity regions, located in the crossing region. The mass of the IDT electrode in the crossing region in the first and second end regions is smaller than the mass of the IDT electrode in the crossing region in the inner region.

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Nagaokakyo, Japan

Yasumasa Taniguchi