# US 2022/0045261 A1 · Piezoelectric device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0045261 A1 - Document ID: US20220045261A1 - Status: Published application - Kind: A1 - Application number: 17/506,921 - Filed: 2021-10-21 - Published: 2022-02-10 - Earliest claimed: 2019-05-16 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Masayuki SUZUKI; Shinsuke IKEUCHI; Fumiya KUROKAWA; Yutaka KISHIMOTO - Web page: https://patentgrep.com/patent/US20220045261A1 ## CPC - H03H 9/174: {Membranes} - H10N 30/871: {Single-layered electrodes of multilayer piezoelectric or electrostrictive devices, e.g. internal electrodes} - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - H03H 9/02015: {Characteristics of piezoelectric layers, e.g. cutting angles} - H10N 30/2047: {Membrane type} - H10N 30/708: {Intermediate layers, e.g. barrier, adhesion or growth control buffer layers} - H03H 2003/023: {the resonators or networks being of the membrane type} - H10N 30/073: by fusion of metals or by adhesives - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract 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. ## Claims ### Claim 1 A piezoelectric device comprising: a base portion; and a membrane portion indirectly supported by the base portion, positioned above the base portion, and including a plurality of layers; wherein the membrane portion does not overlap the base portion and includes a single-crystal piezoelectric layer including a first surface facing upward and a second surface on a side opposite to the first surface in a vertical direction, an upper electrode layer on the first surface, and a lower electrode layer on the second surface so as to face at least a portion of the upper electrode layer sandwiching the single-crystal piezoelectric layer in between; the single-crystal piezoelectric layer is made of lithium tantalate or lithium niobate and includes a plurality of 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; and when viewed in the vertical direction, at least a portion of an upper electrode outer edge that is an outer edge of the upper electrode layer and at least a portion of a lower electrode outer edge that is an outer edge of the lower electrode layer are non-parallel to at least one direction of the plurality of piezoelectric body cleavage directions. ### Claim 2 (depends on 1) The piezoelectric device according to claim 1, wherein an entire or substantially an entire circumference of the upper electrode outer edge and an entire or substantially an entire circumference of the lower electrode outer edge are non-parallel to at least one direction of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 3 (depends on 1) The piezoelectric device according to claim 1, wherein at least a portion of the upper electrode outer edge and at least a portion of the lower electrode outer edge are non-parallel to any of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 4 (depends on 1) The piezoelectric device according to claim 1, wherein an entire or substantially an entire circumference of the upper electrode outer edge and an entire or substantially an entire circumference of the lower electrode outer edge are non-parallel to any of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 5 (depends on 1) The piezoelectric device according to claim 1, wherein the upper electrode outer edge and the lower electrode outer edge each include a plurality of electrode straight portions extending in a straight-line shape when viewed in the vertical direction; and at least a portion of the plurality of electrode straight portions is non-parallel to at least one direction of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 6 (depends on 5) The piezoelectric device according to claim 5, wherein all of the plurality of electrode straight portions are non-parallel to at least one direction of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 7 (depends on 1) The piezoelectric device according to claim 1, wherein the upper electrode outer edge and the lower electrode outer edge each include only a plurality of electrode curved portions extending in a curved-line shape when viewed in the vertical direction. ### Claim 8 (depends on 1) The piezoelectric device according to claim 1, wherein the membrane portion further includes a second single-crystal silicon layer below the lower electrode layer, the second single-crystal silicon layer includes a fourth surface facing upward and a plurality of second silicon cleavage directions extending along a boundary line between a cleavage plane occurring when the second single-crystal silicon layer is cleaved and the fourth surface; and at least a portion of the upper electrode outer edge and at least a portion of the lower electrode outer edge are non-parallel to each of the plurality of second silicon cleavage directions when viewed in the vertical direction. ### Claim 9 (depends on 1) The piezoelectric device according to claim 1, wherein the membrane portion further includes a second single-crystal silicon layer below the lower electrode layer; the second single-crystal silicon layer includes a fourth surface facing upward and a plurality of second silicon cleavage directions extending along a boundary line between a cleavage plane occurring when the second single-crystal silicon layer is cleaved and the fourth surface; the membrane portion surrounded by the base portion when viewed in the vertical direction; and at least a portion of an outer edge of the membrane portion is non-parallel to each of the plurality of second silicon cleavage directions when viewed in the vertical direction. ### Claim 10 (depends on 1) The piezoelectric device according to claim 1, wherein the base portion includes a first single-crystal silicon layer; the first single-crystal silicon layer includes a third surface facing upward and a plurality of first silicon cleavage directions extending along a boundary line between a cleavage plane occurring when the first single-crystal silicon layer is cleaved and the third surface; and at least a portion of the upper electrode outer edge and at least a portion of the lower electrode outer edge are positioned non-parallel to each of the plurality of first silicon cleavage directions when viewed in the vertical direction. ### Claim 11 (depends on 1) The piezoelectric device according to claim 1, wherein the base portion includes a first single-crystal silicon layer; the first single-crystal silicon layer includes a third surface facing upward and a plurality of first silicon cleavage directions extending along a boundary line between a cleavage plane occurring when the first single-crystal silicon layer is cleaved and the third surface; the membrane portion is surrounded by the base portion when viewed in the a vertical direction; and at least a portion of an outer edge of the membrane portion is non-parallel to each of the plurality of first silicon cleavage directions when viewed in the vertical direction. ### Claim 12 (depends on 1) The piezoelectric device according to claim 1, wherein a close contact layer is provided at at least one of between the upper electrode layer and the single-crystal piezoelectric layer and between the lower electrode layer and the single-crystal piezoelectric layer; and the close contact layer is made of a NiCr alloy. ### Claim 13 (depends on 1) The piezoelectric device according to claim 1, wherein a portion in each of the upper electrode layer and the lower electrode layer, which is in contact with the single-crystal piezoelectric layer, is an epitaxial growth film provided on the single-crystal piezoelectric layer. ### Claim 14 (depends on 1) The piezoelectric device according to claim 1, wherein at least one of the base portion and the membrane portion includes a single-crystal silicon layer; the single-crystal silicon layer includes an upper surface facing upward and a plurality of silicon cleavage directions extending along a boundary line between a cleavage plane occurring when the single-crystal silicon layer is cleaved and the upper surface; and at least one direction of the plurality of piezoelectric body cleavage directions is non-parallel to each of the plurality of silicon cleavage directions. ### Claim 15 A piezoelectric device comprising: a base portion; and a membrane portion indirectly supported by the base portion, positioned above the base portion, and including a plurality of layers; wherein the membrane portion does not overlap the base portion and includes a single-crystal piezoelectric layer including a first surface facing upward and a second surface on a side opposite to the first surface in a vertical direction, an upper electrode layer on the first surface, and a lower electrode layer on the second surface so as to face at least a portion of the upper electrode layer sandwiching the single-crystal piezoelectric layer in between; the single-crystal piezoelectric layer is made of lithium tantalate or lithium niobate and includes a plurality of 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; at least one of the base portion and the membrane portion includes a single-crystal silicon layer; the single-crystal silicon layer includes an upper surface facing upward and a plurality of silicon cleavage directions extending along a boundary line between a cleavage plane occurring when the single-crystal silicon layer is cleaved and the upper surface; and at least one direction of the plurality of piezoelectric body cleavage directions is non-parallel to each of the plurality of silicon cleavage directions. ### Claim 16 (depends on 15) The piezoelectric device according to claim 15, wherein an entire or substantially an entire circumference of the upper electrode outer edge and an entire or substantially an entire circumference of the lower electrode outer edge are non-parallel to at least one direction of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 17 (depends on 15) The piezoelectric device according to claim 15, wherein at least a portion of the upper electrode outer edge and at least a portion of the lower electrode outer edge are non-parallel to any of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 18 (depends on 15) The piezoelectric device according to claim 15, wherein an entire or substantially an entire circumference of the upper electrode outer edge and an entire or substantially an entire circumference of the lower electrode outer edge are non-parallel to any of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 19 (depends on 15) The piezoelectric device according to claim 15, wherein the upper electrode outer edge and the lower electrode outer edge each include a plurality of electrode straight portions extending in a straight-line shape when viewed in the vertical direction; and at least a portion of the plurality of electrode straight portions is non-parallel to at least one direction of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction. ### Claim 20 (depends on 19) The piezoelectric device according to claim 19, wherein all of the plurality of electrode straight portions are non-parallel to at least one direction of the plurality of piezoelectric body cleavage directions when viewed in the vertical direction.