Murata Manufacturing Co., Ltd.

Murata Manufacturingco., Ltd.

Yutaka Kishimoto

Tetsuya Kimura

Shinsuke Ikeuchi

Fumiya Kurokawa

Masashi Omura

Katsumi Fujimoto

Masayuki Suzuki

Yuzo Kishi

Seiji Kai

Makoto Sawamura

Masakazu Mimura

Yoichi Mochida

Osamu Nakagawara

Seiji Umezawa

Hideaki Kobayashi

Hiroyuki Seto

Hiromu Okunaga

Yasuyuki Ida

Nobuyoshi Adachi

A piezoelectric element includes a second electrode layer on a second surface of a single-crystal piezoelectric layer. A hole continuous with a through-hole is provided in the second electrode layer. The second electrode layer is made of Pt, Ti, Al, Cu, Au, Ag, Mg, or an alloy including at least one of the metals as a main ingredient. A third electrode layer is on one side of the second electrode layer opposite to the single-crystal piezoelectric layer. The third electrode layer includes at least a portion outside of an edge of the hole with a distance maintained relative to the edge of the hole when viewed in a direction perpendicular or substantially perpendicular to the second surface. The third electrode layer is made of Ni or an alloy including Ni as a main ingredient.

Piezoelectric element

A piezoelectric element includes a piezoelectric layer, a first electrode layer, a second electrode layer, and a connecting electrode. The piezoelectric layer includes first and second surfaces, and a through-hole. The second electrode layer is adjacent to the second surface of the piezoelectric layer. The second electrode layer faces the through-hole. The second electrode layer includes silicon as a major component. The connecting electrode is on a connecting surface of the second electrode layer, and the connecting surface faces the through-hole. The connecting electrode is made of a metal. A surface roughness of the connecting surface is greater than a surface roughness of a major surface. The major surface is a portion, other than the connecting surface, of a surface of the second electrode layer, and the surface is adjacent to the piezoelectric layer.

In a piezoelectric device, a layered portion includes, at a position at least above a recess, a single crystal piezoelectric layer and a pair of electrode layers to apply voltage to the single crystal piezoelectric layer. At least a portion of the pair of electrode layers includes a lower electrode layer extending along a surface of the single crystal piezoelectric layer, the surface being closer to a base. The lower electrode layer is present only inside the recess.

Piezoelectric device

A piezoelectric device includes a base portion and an upper layer on an upper side of and supported by the base portion. The upper layer includes a membrane portion that does not overlap with the base portion in plan view. The membrane portion includes at least one piezoelectric layer sandwiched by electrode layers from a top and a bottom thereof. An intermediate layer is between a lower electrode and the base portion. The intermediate layer includes one or more individual layers, and an individual layer exposed as a lower surface of the membrane portion among the one or more individual layers includes a bent portion, which extends from the lower surface of the membrane portion to a lateral wall, on a boundary between a portion defining and functioning as the lower surface of the membrane portion and a portion overlapping with the base portion.

An elastic wave device includes a piezoelectric layer including a first main surface and a second main surface facing the first main surface, an acoustically reflective layer stacked on the first main surface of the piezoelectric layer, an excitation electrode disposed on the piezoelectric layer, and a support layer. The acoustically reflective layer overlaps at least the excitation electrode in a plan view of the piezoelectric layer from the side of the second main surface. The support layer surrounds the acoustically reflective layer in a plan view of the piezoelectric layer from the side of the second main surface.

Elastic wave device and method for manufacturing the same

A piezoelectric device includes a membrane portion including a single-crystal piezoelectric layer, an upper electrode layer, and a lower electrode layer. The upper electrode layer is on a first surface. The lower electrode layer is on a second surface facing at least a portion of the upper electrode layer sandwiching the single-crystal piezoelectric layer. The single-crystal piezoelectric layer includes piezoelectric body cleavage directions extending along a boundary line between a cleavage plane occurring when the single-crystal piezoelectric layer is cleaved and the first surface. When viewed in a vertical direction, at least a portion of an upper electrode outer edge and at least a portion of a lower electrode outer edge are non-parallel to at least one of the piezoelectric body cleavage directions.

Piezoelectric device including base portion and membrane portion

In a piezoelectric device, a piezoelectric driving portion includes layers and is directly or indirectly supported by a base portion. The piezoelectric driving portion includes a piezoelectric layer, an upper electrode layer, and a lower electrode layer. The upper electrode layer is disposed on the upper side of the piezoelectric layer. The lower electrode layer faces at least a portion of the upper electrode layer with the piezoelectric layer interposed therebetween. The piezoelectric driving portion includes a through groove extending through the piezoelectric driving portion in the vertical direction, so that a pair of inner side surfaces are provided. The pair of inner side surfaces each include a first small-width portion in which the width of the through groove decreases in a downward direction from an upper end surface of the piezoelectric layer.

A piezoelectric device includes a base portion and a membrane portion. The membrane portion is indirectly supported by the base portion, and is located on the upper side relative to the base portion. The membrane portion includes a plurality of layers. The membrane portion does not overlap with the base portion, and includes a single crystal piezoelectric layer, an upper electrode layer, and a lower electrode layer. The membrane portion is provided with a through-groove penetrating in the up-down direction. The through-groove includes a first step portion provided in the thickest layer among the plurality of layers defining the membrane portion. The width of the through-groove is narrower on a lower side than on an upper side with the first step portion as a boundary.

A piezoelectric transducer includes beam portions each with a fixed end portion and extending in a direction away from the fixed end portion. A base portion is connected to the fixed end portion of each of the beam portions. The beam portions extends in a same plane, and respective extending directions of at least two beam portions are different from each other. The beam portions each include a single crystal piezoelectric layer having a polarization axis in a same direction, an upper electrode layer, and a lower electrode layer. A polarization axis has a polarization component in the plane. An axial direction of an orthogonal axis that is orthogonal to the polarization axis and extends in the above-described plane intersects with an extending direction of each of the plurality of beam portions.

Piezoelectric transducer

A MEMS device includes a piezoelectric layer made of a piezoelectric single crystal, a first electrode on a first surface of the piezoelectric layer, and a first layer covering the first surface of the piezoelectric layer. At least a portion of the piezoelectric layer is included in a membrane portion. The first electrode is covered with the first layer and includes a recess. The piezoelectric layer includes a through hole that passes through the piezoelectric layer between a surface of the piezoelectric layer, which is opposite to the first direction, and the recess at a position corresponding to at least a portion of the first electrode.

MEMS device

A piezoelectric device includes a membrane portion and a piezoelectric layer made of single crystal of a piezoelectric body. At least a portion of the piezoelectric layer is included in the membrane portion. An electrode is provided on a surface of the piezoelectric layer in the membrane portion. The piezoelectric layer includes a first polarization region in a first polarization state and a second polarization region in a second polarization state, and the first polarization region and the second polarization region are spaced apart from each other in a thickness direction or an in-plane direction.

An elastic wave device includes a supporting substrate, an acoustic multilayer film on the supporting substrate, a piezoelectric substrate on the acoustic multilayer film, and an IDT electrode on the piezoelectric substrate. An absolute value of a thermal expansion coefficient of the piezoelectric substrate is larger than an absolute value of a thermal expansion coefficient of the supporting substrate. The acoustic multilayer film includes at least four acoustic impedance layers. The elastic wave device further includes a bonding layer provided at any position in a range of from inside the first acoustic impedance layer from the piezoelectric substrate side towards the supporting substrate side, to an interface between the third acoustic impedance layer and the fourth acoustic impedance layer.

Elastic wave device

A MEMS device includes a membrane portion, a piezoelectric layer made of a piezoelectric single crystal, a first electrode on a first surface of the piezoelectric layer, a second electrode on a second surface of the piezoelectric layer opposite to the first direction, and a first layer covering the first surface of the piezoelectric layer. At least a portion of the piezoelectric layer is included in the membrane portion. Each of the first electrode and the second electrode has a tapered cross-sectional shape with a width which decreases with increasing distance from the piezoelectric layer on a cross section along a plane vertical to the surface in the first direction.

A silicon substrate having a first silicon substrate having a first surface with a cavity and a second surface opposite the first surface; a first silicon oxide film having a thickness d1 on the first surface; a second silicon oxide film having a thickness d2 on a bottom of the cavity; and a third silicon oxide film having a thickness d3 on the second surface, where d1&#x2264;d3 and d1&#x3c;d2, or d3&#x3c;d1 and d2&#x3c;d1.

Silicon substrate having cavity and cavity SOI substrate including the silicon substrate

A piezoelectric device includes a piezoelectric single crystal body with a homogeneous polarization state and of which at least a portion flexurally vibrates, an upper electrode on an upper surface of the piezoelectric single crystal body, a lower electrode on a lower surface of the piezoelectric single crystal body, and a supporting substrate below the piezoelectric single crystal body. A recess extends from a lower surface of the supporting substrate toward the lower surface of the piezoelectric single crystal body.

Growing community of inventors

Nagaokakyo, Japan

Yutaka Kishimoto