# US 2019/0379345 A1 · Plate wave devices with wave confinement structures and fabrication methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0379345 A1 - Document ID: US20190379345A1 - Status: Published application - Kind: A1 - Application number: 16/544,279 - Filed: 2019-08-19 - Published: 2019-12-12 - Earliest claimed: 2014-12-17 - Assignees: Qorvo US, Inc. - Applicants: Qorvo US, Inc. - Inventors: Kushal Bhattacharjee - Web page: https://patentgrep.com/patent/US20190379345A1 ## CPC - H03H 9/02244: {of microelectro-mechanical resonators} - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - H03H 9/02228: {Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer} - H03H 9/02275: {Comb electrodes} - H03H 9/02574: {of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate} - H03H 9/25: Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)} - H10N 30/072: by laminating or bonding of piezoelectric or electrostrictive bodies - H10N 30/08: Shaping or machining of piezoelectric or electrostrictive bodies - H10N 30/87: Electrodes or interconnections, e.g. leads or terminals - H03H 2003/027: {the resonators or networks being of the microelectro-mechanical [MEMS] type} - 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 micro-electrical-mechanical system (MEMS) guided wave device includes a single crystal piezoelectric layer and at least one guided wave confinement structure configured to confine a laterally excited wave in the single crystal piezoelectric layer. A bonded interface is provided between the single crystal piezoelectric layer and at least one underlying layer. A multi-frequency device includes first and second groups of electrodes arranged on or in different thickness regions of a single crystal piezoelectric layer, with at least one guided wave confinement structure. Segments of a segmented piezoelectric layer and a segmented layer of electrodes are substantially registered in a device including at least one guided wave confinement structure. ## Claims ### Claim 1 A method of fabricating a micro-electrical-mechanical system (MEMS) guided wave device, the method comprising: locally thinning a single crystal piezoelectric material layer to define a first thickness region and a second thickness region, wherein a thickness of the first thickness region differs from a thickness of the second thickness region; bonding the locally thinned single crystal piezoelectric material layer on or over an underlying layer to provide a bonded interface; defining a first plurality of electrodes arranged on or adjacent to the first thickness region and configured for transduction of a lateral acoustic wave having a wavelength λ1 in the first thickness region; and defining a second plurality of electrodes arranged on or adjacent to the second thickness region and configured for transduction of a lateral acoustic wave having a wavelength λ2 in the second thickness region. ### Claim 2 (depends on 1) The method of claim 1, further comprising planarizing at least one surface of the single crystal piezoelectric material layer prior to the bonding of the locally thinned single crystal piezoelectric material layer on or over the underlying layer. ### Claim 3 (depends on 1) The method of claim 1, further comprising depositing a temperature compensation material on a surface of at least one of the first thickness region or the second thickness region. ### Claim 4 (depends on 3) The method of claim 3, wherein the temperature compensation material comprises a first temperature compensation layer thickness proximate to the first thickness region, and comprises a second temperature compensation layer thickness proximate to the second thickness region, wherein the second temperature compensation layer thickness differs from the first temperature compensation layer thickness. ### Claim 5 (depends on 1) The method of claim 1, wherein the first plurality of electrodes comprises a first interdigital transducer, and the second plurality of electrodes defines a second interdigital transducer. ### Claim 6 (depends on 1) The method of claim 1, wherein the first plurality of electrodes is substantially coplanar with the second plurality of electrodes. ### Claim 7 (depends on 1) The method of claim 1, wherein the first plurality of electrodes is non-coplanar with the second plurality of electrodes. ### Claim 8 (depends on 1) The method of claim 1, wherein the underlying layer comprises at least one of a fast wave propagation layer or a Bragg mirror. ### Claim 9 (depends on 1) The method of claim 1, wherein the underlying layer comprises a substrate. ### Claim 10 A micro-electrical-mechanical system (MEMS) guided wave device comprising: a segmented single crystal piezoelectric layer; a plurality of electrodes arranged in or on the segmented single crystal piezoelectric layer and configured for transduction of a lateral acoustic wave having a wavelength λ in the segmented single crystal piezoelectric layer, wherein the plurality of electrodes comprises a segmented layer of first electrodes; and at least one guided wave confinement structure arranged proximate to the segmented single crystal piezoelectric layer and configured to confine the lateral acoustic wave in the segmented single crystal piezoelectric layer; wherein segments of the segmented single crystal piezoelectric layer are substantially registered with segments of the segmented layer of first electrodes. ### Claim 11 (depends on 10) The MEMS guided wave device of claim 10, wherein the plurality of electrodes further comprises a substantially continuous layer of a second electrode. ### Claim 12 (depends on 10) The MEMS guided wave device of claim 10, comprising gaps between segments of the segmented layer of first electrodes, wherein the gaps are at least partially filled with a slow wave propagation material. ### Claim 13 (depends on 10) The MEMS guided wave device of claim 10, further comprising at least one slow wave propagation material layer between (i) the segmented layer of first electrodes and (ii) the at least one guided wave confinement structure. ### Claim 14 (depends on 10) The MEMS guided wave device of claim 10, wherein the at least one guided wave confinement structure comprises a Bragg mirror. ### Claim 15 (depends on 10) The MEMS guided wave device of claim 10, wherein the at least one guided wave confinement structure comprises a fast wave propagation layer. ### Claim 16 (depends on 10) The MEMS guided wave device of claim 10, wherein: the at least one guided wave confinement structure comprises a first guided wave confinement structure and a second guided wave confinement structure; gaps between segments of the segmented layer of first electrodes, and gaps between segments of the segmented single crystal piezoelectric layer, are filled with a slow wave propagation material; and the plurality of electrodes, the segmented single crystal piezoelectric layer, and the slow wave propagation material are arranged between the first guided wave confinement structure and the second guided wave confinement structure. ### Claim 17 (depends on 16) The MEMS guided wave device of claim 16, wherein each of the first guided wave confinement structure and the second guided wave confinement structure comprises a Bragg mirror. ### Claim 18 (depends on 16) The MEMS guided wave device of claim 16, wherein each of the first guided wave confinement structure and the second guided wave confinement structure comprises a fast wave propagation layer. ### Claim 19 (depends on 16) The MEMS guided wave device of claim 16, wherein one of the first guided wave confinement structure or the second guided wave confinement structure comprises a Bragg mirror, and the other of the first guided wave confinement structure or the second guided wave confinement structure comprises a fast wave propagation layer. ### Claim 20 (depends on 16) The MEMS guided wave device of claim 16, further comprising at least one slow wave propagation material layer between (i) the segmented layer of first electrodes and (ii) at least one of the first guided wave confinement structure or the second guided wave confinement structure.