Surface acoustic wave device with decoupling interdigital capacitor

Abstract

Certain aspects of the present disclosure provide an electro-acoustic device and a method of manufacturing such an electro-acoustic device. One example electro-acoustic device generally includes a piezoelectric layer (430), a surface acoustic wave (SAW) resonator (410) disposed above the piezoelectric layer, a non-piezoelectric region (440) disposed adjacent to the piezoelectric layer, and an interdigital transducer capacitor (420) IDC electrically coupled to the SAW resonator and disposed above the non-piezoelectric region.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit and priority of U.S. Application No. 18 / 543,953, filed December 18, 2023, which has been assigned to the assignee of this application and is expressly incorporated herein by reference in its entirety, as fully set forth below and for all applicable purposes. Technical Field

[0003] Certain aspects of this disclosure relate generally to electronic components, and more specifically to surface acoustic wave (SAW) devices. Background Technology

[0004] Electronic devices include traditional computing devices such as desktop computers, laptops, tablets, smartphones, wearable devices such as smartwatches, and internet servers. These diverse electronic devices provide human users with information, entertainment, social interaction, security, safety, productivity, transportation, manufacturing, and other services. Many of the functions of these diverse electronic devices rely on wireless communication. Wireless communication systems and devices are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, and broadcasting. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems (e.g., Long Term Evolution (LTE) systems or New Radio (NR) systems).

[0005] The wireless communication transceivers used in these electronic devices typically include multiple radio frequency (RF) filters for filtering signals at specific frequencies or frequency ranges. Electroacoustic devices (e.g., "acoustic filters") are used in many applications to filter high-frequency (e.g., typically greater than 100 MHz) signals. Using piezoelectric materials as the vibrating medium, acoustic resonators operate by converting electrical signal waves propagating along an electrical conductor into sound waves propagating via the piezoelectric material. Sound waves propagate at speeds much smaller than the propagation speed of electromagnetic waves. Generally, the propagation speed of a wave is proportional to its wavelength. Therefore, after converting an electrical signal into an acoustic signal, the wavelength of the acoustic signal wave is significantly smaller than the wavelength of the electrical signal wave. The resulting smaller wavelength of the acoustic signal allows for the use of smaller filter devices to perform filtering. This allows the use of acoustic resonators in size-constrained electronic devices such as those listed above (e.g., specifically portable electronic devices such as smartphones).

[0006] Today, surface acoustic wave (SAW) or bulk acoustic wave (BAW) components are used in wireless communication devices, such as for implementing RF filters. In SAW technology, acoustic waves propagate laterally across the surface of a piezoelectric substrate, where the movement of the piezoelectric material is generated by interdigitated metal transducers (IDTs) on the surface. The wavelength of the acoustic wave can be defined by the pitch of the IDT (e.g., the width of the metal fingers and the gap). In BAW technology, acoustic waves propagate vertically through a three-dimensional structure, where an electric field is applied through electrodes above and below the piezoelectric material. In this case, the wavelength is defined by the thickness of the piezoelectric material.

[0007] In one type of SAW device, surface acoustic waves are generated by the input IDT and detected by the output IDT. In another type of SAW device, reflectors on either side of the IDT can be used to confine the acoustic energy. A planar resonant cavity created between two mirrors consisting of reflective metal strips can also be used to capture acoustic energy.

[0008] As the number of frequency bands used in wireless communication increases and as the desired bandwidth of filters widens, the performance of acoustic filters becomes increasingly important in reducing losses and improving the overall performance of electronic devices. Acoustic filters with improved performance, especially those with reduced intermodulation distortion, are therefore highly sought after. Summary of the Invention

[0009] The systems, methods, and apparatus of this disclosure each have several aspects, none of which is solely responsible for its desired properties. Without limiting the scope of this disclosure as set forth in the following claims, some features will now be briefly discussed. After considering these discussions, and particularly after reading the section entitled “Detailed Description,” one will understand how the features of this disclosure provide advantages, including enhanced radio frequency (RF) filter performance.

[0010] Certain aspects of this disclosure provide an electroacoustic device. The electroacoustic device typically includes: a piezoelectric layer; a surface acoustic wave (SAW) resonator disposed above the piezoelectric layer; a first non-piezoelectric region disposed adjacent to the piezoelectric layer; and an interdigital capacitor (IDC) electrically coupled to the SAW resonator and disposed above the first non-piezoelectric region.

[0011] Certain aspects of this disclosure provide a filter circuit. This filter circuit typically includes multiple resonators and capacitors electrically coupled to the resonators, wherein the capacitors and resonators respectively include the IDC and SAW resonators of the electroacoustic device described herein.

[0012] Certain aspects of this disclosure provide a wireless device. A wireless device typically includes at least one of the electroacoustic device described herein and an antenna or radio frequency (RF) circuitry coupled to the electroacoustic device.

[0013] Certain aspects of this disclosure provide a method for manufacturing an electroacoustic device. The method typically includes forming a first non-piezoelectric region adjacent to a piezoelectric layer, forming a SAW resonator over the piezoelectric layer, and forming an IDC over the first non-piezoelectric region.

[0014] To achieve the foregoing and related objectives, one or more aspects include the features fully described below and specifically pointed out in the claims. The following description and drawings illustrate certain exemplary features of these one or more aspects in detail. However, these features indicate only a few of the various ways in which the principles of the various aspects may be employed. Attached Figure Description

[0015] To gain a more detailed understanding of the foregoing features of this disclosure, reference can be made to various aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain aspects of this disclosure and should therefore not be considered as limiting its scope, as the description may allow for other equivalent aspects.

[0016] Figure 1A This is a perspective view of an example electroacoustic device in which certain aspects of this disclosure can be practiced.

[0017] Figure 1B yes Figure 1A A cross-sectional view of an example electroacoustic device.

[0018] Figure 2A This is a top view of an example electrode structure for an electroacoustic device, in which certain aspects of this disclosure can be practiced.

[0019] Figure 2B This is a top view of another example electrode structure of an electroacoustic device, in which some aspects of this disclosure can be practiced.

[0020] Figure 3A This is a perspective view of an example electroacoustic device in which certain aspects of this disclosure may be implemented.

[0021] Figure 3B yes Figure 3A A cross-sectional view of an example electroacoustic device.

[0022] Figure 4A This is a top view illustration of an example electroacoustic device according to certain aspects of this disclosure, the electroacoustic device including a surface acoustic wave (SAW) resonator and an interdigital capacitor (IDC).

[0023] Figure 4B This is a top view illustration of an example electroacoustic device according to certain aspects of this disclosure, the electroacoustic device including a SAW resonator and an IDC decoupled from the piezoelectric layer of the electroacoustic device.

[0024] Figure 4C This is a top view of another example electroacoustic device according to certain aspects of this disclosure, the electroacoustic device including a SAW resonator and an IDC decoupled from the piezoelectric layer of the electroacoustic device.

[0025] Figure 5A This is a cross-sectional view of an electroacoustic device having an IDC decoupled from the piezoelectric layer of the electroacoustic device, according to certain aspects of this disclosure.

[0026] Figure 5B This is a cross-sectional view of another electroacoustic device having an IDC decoupled from the piezoelectric layer of the electroacoustic device, according to certain aspects of this disclosure.

[0027] Figure 6 This is a flowchart depicting an example operation for manufacturing an electroacoustic device according to certain aspects of this disclosure.

[0028] Figure 7 Schematic diagrams and specific implementations of electroacoustic filter circuits according to certain aspects of this disclosure are illustrated.

[0029] Figure 8 This is a functional block diagram of at least a portion of an example simplified wireless transceiver circuit, in which an electroacoustic filter circuit may be employed.

[0030] Figure 9 It is a diagram of an environment including an electronic device having a wireless transceiver, such as... Figure 8 The transceiver circuit.

[0031] For ease of understanding, the same reference numerals have been used where possible to denote common elements in the figures. It is conceivable that elements disclosed in one aspect may be usefully applied to other aspects without specific description. Detailed Implementation

[0032] Certain aspects of this disclosure generally relate to an electroacoustic device having one or more interdigitated capacitors (IDCs) decoupled from a piezoelectric layer of the electroacoustic device. Such an electroacoustic device may include a piezoelectric layer, a surface acoustic wave (SAW) resonator disposed above the piezoelectric layer, a non-piezoelectric region disposed adjacent to the piezoelectric layer, and one or more IDCs electrically coupled to the SAW resonator and disposed above the non-piezoelectric region. In this manner, no portion of the piezoelectric layer is disposed between the IDCs and the non-piezoelectric region, such that the one or more IDCs are decoupled from the piezoelectric layer. In some aspects, the non-piezoelectric region may be disposed within a cavity of the piezoelectric layer.

[0033] The specific embodiments described below with reference to the accompanying drawings are intended as descriptions of exemplary embodiments and are not intended to represent the only specific embodiments in which aspects of this disclosure may be practiced. The term "exemplary" as used throughout this specification means "serving as an example, instance, or illustration" and should not be construed as superior to or better than other exemplary embodiments. The specific embodiments include particular details for the purpose of providing a thorough understanding of the exemplary embodiments. In some instances, some devices are shown in block diagram form. Drawing elements common in the following drawings may be identified using the same reference numerals.

[0034] Example electroacoustic equipment

[0035] Figure 1A This is a perspective view of an example electroacoustic device 100. Electroacoustic device 100 may be configured as or may be part of a SAW resonator. In some descriptions herein, electroacoustic device 100 may be referred to as a SAW resonator. However, other types of electroacoustic devices may exist that can be constructed based on the principles described herein.

[0036] Electroacoustic device 100 includes an electrode structure 104, referred to as an interdigital transducer (IDT), located on the surface of a piezoelectric material 102. The electrode structure 104 typically includes a first comb-shaped electrode structure and a second comb-shaped electrode structure (conductive and typically metallic), wherein electrode fingers extend from two busbars toward each other and are arranged in an interlocking manner between the two busbars (e.g., in an interdigital arrangement, as shown). An electrical signal excited (e.g., by applying an AC voltage) in the electrode structure 104 is converted into an acoustic wave 106, which propagates in a specific direction via the piezoelectric material 102. The acoustic wave 106 is converted back into an electrical signal and provided as an output. In many applications, the piezoelectric material 102 has a specific crystal orientation such that when the electrode structure 104 is arranged relative to the crystal orientation of the piezoelectric material 102, the acoustic wave propagates primarily in a direction perpendicular to the fingers (e.g., parallel to the busbars).

[0037] Figure 1B yes Figure 1A The electroacoustic equipment 100 along Figure 1AThe diagram shows a cross-sectional view of section 108. The electroacoustic device 100 is exemplified by a simplified layer stack comprising a piezoelectric material 102, wherein an electrode structure 104 is disposed on the piezoelectric material 102. The electrode structure 104 is conductive and is typically formed of a metallic material. Alternatively, the electrode structure 104 may be formed of a conductive but non-metallic material (e.g., graphene). The piezoelectric material 102 can be formed of various materials, such as quartz, lithium tantalate (LiTaO3), lithium niobate (LiNbO3), doped variants of these, other piezoelectric materials, or other crystals. The piezoelectric material 102 may be referred to as a "piezoelectric substrate," but may also be referred to as a "piezoelectric layer," as in examples where an additional layer exists beneath the piezoelectric material 102.

[0038] It should be understood that more complex layer stacks, including layers of various materials, are possible within this stack. For example, optionally, a temperature compensation layer 110, indicated by dashed lines, may be provided above the electrode structure 104. The piezoelectric material 102 may be extended with multiple interconnected electrode structures disposed thereon to form a multi-resonator filter or provide multiple filters. Although not illustrated, a capping layer may be provided above the electrode structure 104 when disposed as an integrated circuit component. The capping layer is applied such that a cavity is formed between the electrode structure 104 and the lower surface of the capping layer. Electrical vias or bumps may also be included to allow electrical connection of the component to a connector on the substrate (e.g., via flip chip or other techniques).

[0039] Figure 2A This is a top view of an example electrode structure 204a for an electroacoustic device. The electrode structure 204a has an IDT 205, which includes a first busbar 222 (e.g., a first conductive segment or conductive trunk) electrically coupled to a first terminal 220 and a second busbar 224 (e.g., a second conductive segment or conductive trunk) spaced apart from the first busbar 222 and coupled to a second terminal 230. A plurality of conductive fingers 226 are interdigitatedly connected to either the first busbar 222 or the second busbar 224. The fingers 226 connected to the first busbar 222 extend toward the second busbar 224 but are not connected to the second busbar 224, such that a small gap exists between the ends of these fingers 226 and the second busbar 224. Similarly, the fingers 226 connected to the second busbar 224 extend toward the first busbar 222 but are not connected to the first busbar 222, such that a small gap exists between the ends of these fingers 226 and the first busbar 222. Similarly, small gaps can also be formed between the finger 226 and any structure (e.g., a truncated finger) extending from the first busbar 222 or the second busbar 224.

[0040] Between the busbars, there exists an overlapping region comprising a central region where a portion of one finger overlaps with a portion of an adjacent finger, as illustrated by central region 225. This central region 225, including the overlap, may be referred to as an aperture, track, or active region, in which an electric field is generated between the fingers 226 to allow sound waves to propagate in this region of the piezoelectric material 102. The periodicity of the fingers 226 is referred to as the pitch of the IDT. The pitch can be indicated in various ways. For example, in some aspects, the pitch may correspond to the magnitude of the distance between the fingers in central region 225. This distance may be defined, for example, as the distance between the center points of each of these fingers (and when the fingers have a uniform width, it is typically measured between the right (or left) edge of one finger and the right (or left) edge of an adjacent finger). In some aspects, the average distance between adjacent fingers may be used as the pitch. The frequency of the piezoelectric material's vibration is the dominant resonant frequency of the electrode structure 204a. The frequency is determined at least in part by the pitch of the IDT 205 and other characteristics of the electroacoustic device 100.

[0041] An IDT 205 is arranged between two reflectors 228 that reflect sound waves toward the IDT 205 back to convert the sound waves into electrical signals via the IDT 205 in the illustrated configuration, and to prevent losses (e.g., limiting and preventing sound wave escape). Each reflector 228 has a grid structure with two buses and conductive fingers, each connected to one of the two buses. The pitch of the reflectors may be similar to or the same as the pitch of the IDT 205 to reflect sound waves within the resonant frequency range. However, many configurations are possible.

[0042] When converted back to an electrical signal, the converted electrical signal can be provided as an output, such as one of the first terminal 220 or the second terminal 230, while the other terminal can be used as an input.

[0043] Multiple electrode structures are possible. Figure 2A A single-port configuration can be broadly illustrated. Other configurations (e.g., dual-port configurations) are also possible. For example, electrode structure 204a may have an input IDT 205, where each terminal 220 and 230 serves as an input terminal. In this case, an adjacent output IDT (not shown) positioned between reflectors 228 and adjacent to the input IDT 205 can be provided to convert the acoustic waves propagating in the piezoelectric material 102 into electrical signals to be provided at the output terminals of the output IDTs.

[0044] Figure 2BThis is a top view of another example electrode structure 204b for an electroacoustic device. In this case, a dual-mode SAW (DMS) electrode structure 204b is illustrated; a DMS structure is a structure capable of inducing multiple resonances. Electrode structure 204b includes multiple IDTs arranged between reflectors 228 and connected as shown. Electrode structure 204b is provided to illustrate various electrode structures in which the principles described herein can be applied.

[0045] It should be understood that although a certain number of fingers 226 are illustrated, the actual number of fingers, as well as the length and width of the fingers 226 and the bus, may differ in actual implementations. These parameters depend on the specific application and desired filter characteristics. Furthermore, the SAW filter may include multiple interconnect electrode structures, each including multiple IDTs to achieve a desired passband (e.g., multiple interconnect resonators or IDTs to form the desired filter transfer function).

[0046] Figure 3A This is a perspective view of another example of an electroacoustic device 300. The electroacoustic device 300 (e.g., which may be configured as a SAW resonator or a portion thereof) is similar to... Figure 1A Electroacoustic device 100, but with different layer stacks. Specifically, electroacoustic device 300 includes a thin piezoelectric material 302 provided on a substrate 310 (e.g., silicon). In some cases, electroacoustic device 300 may be referred to as a thin-film SAW resonator (TF-SAW). The choice of piezoelectric material 302 depends on the type used (e.g., typically relative to...). Figure 1A The electroacoustic device 100 has a higher coupling factor and a controlled thickness of the piezoelectric material 302, and the specific acoustic wave mode excited can be... Figure 1A The sound wave modes in the electroacoustic device 100 are slightly different. Based on the design (layer thickness and material selection, etc.), and... Figure 1A Compared to electroacoustic device 100, electroacoustic device 300 may have a higher quality factor (Q). Generally, substrate 310 may be substantially thicker than piezoelectric material 302 (e.g., about 50 to 100 times thicker, or more). Substrate 310 may include other layers (or other layers may be included between substrate 310 and piezoelectric material 302).

[0047] Figure 3B yes Figure 3A A cross-sectional view of the electroacoustic device 300 is shown, illustrating an exemplary layer stack (along section 307). Figure 3BIn the example shown, substrate 310 may include sublayers that may have higher resistance (e.g., higher resistivity layers relative to other layers), such as substrate sublayer 310-1 (e.g., made of silicon). Substrate 310 may also include a well-rich layer 310-2 (e.g., polycrystalline silicon). Substrate 310 may also include a compensation layer 310-3 (e.g., silicon dioxide (SiO2) or another dielectric material) that can provide temperature compensation and other properties. These sublayers may be considered as part of substrate 310 or as separate layers on their own. A relatively thin piezoelectric material 302 is provided on substrate 310 at a specific thickness to provide a specific acoustic mode (e.g., with...). Figure 1A Compared to the electroacoustic device 100, the thickness of the piezoelectric material 102 is not a critical design parameter exceeding a certain thickness, and compared with... Figure 3A and Figure 3B The piezoelectric material 302 of the electroacoustic device 300 may be thicker than it would typically be. The electrode structure 304 is positioned above the piezoelectric material 302. In addition, in some aspects, one or more layers (not shown) (e.g., a thin passivation layer) may be present above the electrode structure 304.

[0048] Based on the type, thickness, and overall layer stacking of the piezoelectric material, the coupling to the electrode structure 304 and the sound velocity within the piezoelectric material in different regions of the electrode structure 304 can vary between different types of electroacoustic devices (such as...). Figure 1A Electroacoustic equipment 100 and Figure 3A and Figure 3B The electroacoustic equipment (300) varies.

[0049] Example electroacoustic device with interdigitated capacitors (IDC)

[0050] Some electroacoustic devices (e.g., SAW devices) may include an IDC to improve the skirt steepness (e.g., transition band) of filters implemented by the electroacoustic device. The IDC can be integrated into the electroacoustic device and can utilize a structure similar to that of a SAW resonator implemented as an IDT, but can resonate at a higher frequency to minimize (or at least reduce) in-band losses in the electroacoustic device. Figure 4A This is a top view illustration of an example electroacoustic device 400A according to certain aspects of this disclosure, which includes a surface acoustic wave (SAW) resonator and an IDC. Although only a single IDC is illustrated in the figures and mentioned herein, any number of IDCs may be utilized in the electroacoustic device described herein.

[0051] like Figure 4AAs shown, the electroacoustic device 400A may include a SAW resonator 410 (which may be implemented as an IDT) and an IDC 420, both disposed above a piezoelectric layer 430 (e.g., piezoelectric materials 102, 302). The IDC 420 is electrically coupled to the SAW resonator 410 via conductive traces 435. The SAW resonator 410 may include an array of conductive fingers 415 (e.g., fingers 226) aligned in a first direction, and the IDC 420 may include an array of conductive fingers 425 (e.g., similar to fingers 226) also aligned in the first direction. In this way, the array of conductive fingers 415 in the SAW resonator 410 and the array of conductive fingers 425 in the IDC 420 are aligned in the same direction.

[0052] exist Figure 4A In the electroacoustic device 400A, the IDC 420 is disposed above and coupled to the piezoelectric layer 430. As a result, spurious modes may exist in any filter implemented by the electroacoustic device 400A. Furthermore, because the IDC 420 resonates at a higher frequency than the SAW resonator 410, the pitch of the IDC 420 can be smaller. Due to this smaller pitch, the capacitance of the IDC 420 may vary significantly between different electroacoustic devices produced due to variations in finger width that occur during manufacturing.

[0053] Some aspects of this disclosure relate to an electroacoustic device utilizing an IDC decoupled from the piezoelectric layer of the electroacoustic device. In this way, spurious modes in any filter implemented by the electroacoustic device can be removed or at least reduced.

[0054] Figure 4B This is a top view illustration of an example electroacoustic device 400B according to certain aspects of this disclosure, which includes a SAW resonator and an IDC decoupled from a piezoelectric layer included in the electroacoustic device. Electroacoustic device 400B may be similar to electroacoustic device 400A, but with the addition of a non-piezoelectric region 440 disposed below the IDC 420 (e.g., adjacent to the piezoelectric layer 430), as... Figure 4B As shown. In some respects, no part of the piezoelectric layer 430 is disposed between the IDC 420 and the non-piezoelectric region 440, thereby decoupling the IDC 420 from the piezoelectric layer 430.

[0055] The array of conductive fingers 415 included in the SAW resonator 410 can be aligned in the same direction as the array of conductive fingers 425 included in the IDC 420. As a result, it is easier and less costly to manufacture the arrays of conductive fingers 415 included in the SAW resonator 410 and the arrays of conductive fingers 425 included in the IDC 420.

[0056] Figure 4CThis is a top view illustration of another example electroacoustic device according to certain aspects of this disclosure, which includes a SAW resonator and an IDC decoupled from a piezoelectric layer included in the electroacoustic device. Electroacoustic device 400C may be similar to electroacoustic device 400B, but the array of conductive fingers 415 included in the SAW resonator 410 may be aligned in a different direction than the array of conductive fingers 425 included in the IDC 420. For example, the array of conductive fingers 415 included in the SAW resonator 410 may be aligned in a first direction, while the array of conductive fingers 425 included in the IDC 420 may be aligned in a second direction perpendicular to the first direction, such as... Figure 4C As shown.

[0057] Figure 5A This is a cross-sectional view of an electroacoustic device 500A having an IDC 420 decoupled from the piezoelectric layer 430 of the electroacoustic device, according to certain aspects of this disclosure. In some aspects, the electroacoustic device 500A can be implemented as a SAW resonator, which can be a thin-film SAW (TF-SAW) resonator.

[0058] like Figure 5A As shown, the electroacoustic device 500A may include a SAW resonator 410 disposed above the piezoelectric layer 430 and an IDC 420 disposed above the non-piezoelectric region 440. The SAW resonator 410 may include an array of conductive fingers 415, and the IDC 420 may include an array of conductive fingers 425. The piezoelectric layer 430 may be disposed above a substrate 310, which may include a substrate sublayer 310-1, a well-rich layer 310-2, and a compensation layer 310-3, as described above. The compensation layer 310-3 may be referred to as a temperature compensation layer and may be disposed below the first non-piezoelectric region 440. The temperature compensation layer may include, for example, silicon dioxide (SiO2) or be formed of, for example, silicon dioxide. In other aspects, the substrate 310 may not be included in the electroacoustic device 500A, and the piezoelectric layer 430 may be implemented as a piezoelectric substrate (e.g., a bulk piezoelectric layer).

[0059] As described above, the non-piezoelectric region 440 may be disposed adjacent to the piezoelectric layer 430. In some aspects, no portion of the piezoelectric layer 430 is disposed between the IDC 420 and the non-piezoelectric region 440, thereby decoupling the IDC 420 from the piezoelectric layer 430. The non-piezoelectric region 440 may be disposed within a cavity 545 of the piezoelectric layer 430. The cavity 545 may be implemented by recesses (e.g., truncated conical recesses), channels, grooves, cavities, trenches, etc. In some aspects, the cavity 545 may extend from the top surface of the piezoelectric layer 430 to the bottom surface of the piezoelectric layer 430, such as... Figure 5AAs shown. In other aspects, the cavity 545 may not extend from the top surface of the piezoelectric layer 430 to the bottom surface of the piezoelectric layer 430, such that a portion of the piezoelectric layer 430 (e.g., the bottom) is disposed below the non-piezoelectric region 440 (e.g., the piezoelectric layer 430 is continuous throughout the electroacoustic device 500A). In other aspects, the cavity 545 may extend from the top surface of the piezoelectric layer 430 to a portion of the substrate 310 (e.g., to at least a portion of the compensation layer 310-3). For some aspects, the depth of the non-piezoelectric region 440 may be at least two wavelengths, where the wavelengths may correspond to the center frequency of the bandpass filter response of the electroacoustic device.

[0060] like Figure 5A As shown, the top surface of the piezoelectric layer 430 and the top surface of the non-piezoelectric region 440 can be coplanar. In other respects, the top surface of the non-piezoelectric region 440 can be lower than the top surface of the piezoelectric layer 430, or the top surface of the non-piezoelectric region 440 can be higher than the top surface of the piezoelectric layer 430.

[0061] The non-piezoelectric region 440 may include a dielectric material. The dielectric material may include, or be made of, any of silicon dioxide (SiO2), tantalum pentoxide (Ta2O5), or various other suitable non-piezoelectric dielectric materials.

[0062] like Figure 5A As shown, the distance between the top of the conductive finger 415 included in the SAW resonator 410 and the top surface of the piezoelectric layer 430 is different from the distance between the top of the conductive finger 425 included in the IDC 420 and the top surface of the non-piezoelectric region 440. In other words, the height of the conductive finger 415 included in the SAW resonator 410 and the height of the conductive finger 425 included in the IDC 420 can be different. In other respects, the distance between the top of the finger included in the SAW resonator 410 and the piezoelectric layer 430 and the distance between the top of the finger included in the IDC 420 and the non-piezoelectric region 440 can be the same. In these respects, the height of the conductive finger 415 included in the SAW resonator 410 and the height of the conductive finger 425 included in the IDC 420 are the same.

[0063] Figure 5B This is a cross-sectional view of another electroacoustic device 500B having an IDC 420 decoupled from the piezoelectric layer 430 of the electroacoustic device, according to certain aspects of this disclosure. Electroacoustic device 500B may be similar to electroacoustic device 500A, but the non-piezoelectric region 440 may be implemented using a variety of different non-piezoelectric materials. For example... Figure 5BAs shown, the non-piezoelectric region 440 can be implemented as a first non-piezoelectric region 540 and a second non-piezoelectric region 550. The second non-piezoelectric region 550 can be disposed below the first non-piezoelectric region 540, such as... Figure 5B As shown, or vice versa. The first non-piezoelectric region 540 may include a first material, and the second non-piezoelectric region 550 may include a second material different from the first material. The first material may have a higher, lower, or the same dielectric constant than the second material. In this way, the capacitance characteristics of the IDC 420 in the electroacoustic device 500B can be modified.

[0064] In some respects, filter circuits (e.g., the following about...) Figure 7 The described filter circuit 700 may include a plurality of resonators and capacitors electrically coupled to the resonators, and the capacitors and resonators may each include electroacoustic devices (e.g., Figure 5A or Figure 5B The IDC 420 and SAW resonator 410 of the electroacoustic equipment (500A, 500B).

[0065] In some respects, wireless devices (e.g., the following about...) Figure 9 The described electronic device 902) may include electroacoustic devices (e.g., respectively) Figure 5A or Figure 5B The electroacoustic devices 500A and 500B, and the wireless devices may also include at least one of an antenna or a radio frequency (RF) circuit coupled to the electroacoustic devices.

[0066] Example operation for manufacturing electroacoustic equipment

[0067] Figure 6 It describes, according to certain aspects of this disclosure, the manufacture of electroacoustic devices (e.g., respectively). Figure 4A , Figure 4B , Figure 4C , Figure 5A or Figure 5B The flowchart illustrates example operations 600 of electroacoustic devices 400A, 400B, 400C, 500A, and 500B. These operations 600 are described as a set of boxes specifying executable operations. However, the operations are not necessarily limited to... Figure 6 The order shown or described herein is not specified, as these operations can be performed in an alternative order or in a manner that is wholly or partially overlapping. Furthermore, more, fewer, and / or different operations can be performed to execute operation 600. Operation 600 can be performed, for example, by a semiconductor manufacturing facility (also known as a “manufacturing plant”) or other facilities for the manufacture of electroacoustic devices.

[0068] Operation 600 may begin at block 602, wherein a fabrication facility forms a first non-piezoelectric region (e.g., first non-piezoelectric region 440, 540) adjacent to a piezoelectric layer (e.g., piezoelectric layer 430). According to some aspects, forming the first non-piezoelectric region includes forming a cavity (e.g., cavity 545) in the piezoelectric layer and depositing a first non-piezoelectric material in the cavity to form the first non-piezoelectric region. In some cases, the first non-piezoelectric material may completely fill the cavity, while in other cases, the first non-piezoelectric material may partially fill the cavity. Forming the cavity may include removing a portion of the piezoelectric layer. Removing the portion of the piezoelectric layer may include etching (e.g., dry etching) the piezoelectric layer to form the cavity. Any other suitable removal process may also be used to form the cavity. In some aspects, the first non-piezoelectric material may include a dielectric material (e.g., tantalum pentoxide, silicon dioxide, etc.).

[0069] At frame 604, the manufacturing facility may form a SAW resonator (e.g., SAW resonator 410) over the piezoelectric layer.

[0070] At frame 606, the manufacturing facility may form an IDC (e.g., IDC 420) above the first non-piezoelectric region.

[0071] According to some aspects, operation 600 may further include forming a second non-piezoelectric region adjacent to the piezoelectric layer (e.g., a second non-piezoelectric region 550). In this case, forming the first non-piezoelectric region may include forming the first non-piezoelectric region over the second non-piezoelectric region. In some aspects, the first non-piezoelectric region comprises a first material, and the second non-piezoelectric region comprises a second material different from the first material. The first material may have a higher dielectric constant than the second material, the same dielectric constant as the second material, or a lower dielectric constant than the second material. For example, the first material may be tantalum pentoxide, and the second material may be silicon dioxide.

[0072] Each of the layers or regions described above can be formed using any suitable technique used in the production of electroacoustic devices. For example, these layers can be formed using electron beam evaporation and stripping processes.

[0073] Example applications of electroacoustic equipment

[0074] Figure 7 A schematic diagram of an electroacoustic filter circuit 700 according to certain aspects of this disclosure is illustrated. This electroacoustic filter circuit may include electroacoustic devices with decoupled IDCs, such as… Figure 5A 500A or electroacoustic equipment Figure 5BThe electroacoustic device 500B. A filter circuit 700 provides an example of a SAW device that can be used. The filter circuit 700 includes an input terminal 702 and an output terminal 714. A ladder network of SAW resonators is provided between the input terminal 702 and the output terminal 714. The filter circuit 700 includes a first SAW resonator 704, a second SAW resonator 706, a third SAW resonator 708, and a fourth SAW resonator 709, all electrically connected in a series path between the input terminal 702 and the output terminal 714. A fifth SAW resonator 710 (e.g., a parallel resonator) has a first terminal connected between the first SAW resonator 704 and the second SAW resonator 706, and a second terminal connected to a reference potential node 730 (e.g., electrically grounded) of the filter circuit 700. The sixth SAW resonator 712 (e.g., a parallel resonator) has a first terminal connected between the second SAW resonator 706 and the third SAW resonator 708, and a second terminal connected to the reference potential node 730. The seventh SAW resonator 713 (e.g., a parallel resonator) has a first terminal connected between the third SAW resonator 708 and the fourth SAW resonator 709, and a second terminal connected to the reference potential node 730.

[0075] In some respects, the electroacoustic filter circuit 700 may include at least one capacitor element. Figure 7 (not shown in the example), it can be provided by IDC (e.g., Figures 4A to 4C and Figures 5A to 5B The capacitor (IDC 420) is implemented and can be connected in series or parallel in the filter circuit 700. Such a capacitor can replace... Figure 7 One of the SAW resonators shown can be coupled in series or in parallel.

[0076] Figure 8 This is one of the options that can be adopted. Figure 7This is a functional block diagram of at least a portion of an example of a simplified wireless transceiver circuit 800, such as filter circuit 700 (or other filters as described herein for wireless transmission using electroacoustic devices with decoupled IDCs). Transceiver circuit 800 is configured to receive a signal / information (shown as in-phase (I) and quadrature (Q) values) for transmission provided to one or more baseband (BB) filters 812. The filtered output is provided to one or more mixers 814 for upconversion to a radio frequency (RF) signal. The output from one or more mixers 814 can be provided to a driver amplifier (DA) 816, the output of which can be provided to a power amplifier (PA) 818 to produce an amplified signal for wireless transmission. The amplified signal is output to antenna 822 via one or more filters 820 (e.g., a duplexer (if used as a frequency division duplex transceiver) or other filters). One or more filters 820 may include... Figure 7 The filter circuit 700 (or another filter for wireless transmission using an electroacoustic device with one or more decoupled IDCs, as described herein).

[0077] Antenna 822 can be used to wirelessly transmit data and receive signals. Transceiver circuitry 800 includes the following receiving path: before the signal is further processed (e.g., provided to an analog-to-digital converter (ADC) and subsequently demodulated or otherwise processed in the digital domain), it passes through one or more filters 820 to be supplied to a low-noise amplifier (LNA) 824 and additional filters 826, and is subsequently down-converted from the received frequency to a baseband frequency by one or more mixer circuits 828. Separate filters may be present for the receiving circuitry (e.g., the receiving circuitry may have a separate antenna or a separate receiving filter), which can be used... Figure 7 The filter circuit 700 (or another filter for wireless transmission using an electroacoustic device with one or more decoupled IDCs, as described herein) is used to implement this.

[0078] Figure 9This is a diagram of an environment 900 including electronic device 902, in which various aspects of the present disclosure can be practiced. In environment 900, electronic device 902 communicates with base station 904 (or other network node) via wireless link 906. As shown, electronic device 902 is depicted as a smartphone. However, electronic device 902 can be implemented as any suitable computing device or other electronic device, such as a cellular base station, broadband router, access point, cellular or mobile phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, server computer, network attached storage (NAS) device, smart appliance, vehicle-based communication system, Internet of Things (IoT) device, sensor or security device, asset tracker, extended reality device, wearable device, etc.

[0079] Base station 904 communicates with electronic device 902 via wireless link 906, which can be implemented as any suitable type of wireless link. Although depicted as a base station tower of a cellular radio network, base station 904 can represent or be implemented as another device, such as a satellite, terrestrial broadcast tower, access point, peer device, mesh network node, fiber optic line, or another electronic device generally described above. Therefore, electronic device 902 can communicate with base station 904 or another device via wired connection, wireless connection, or a combination thereof. Wireless link 906 can include a downlink transmitting data or control information from base station 904 to electronic device 902, and an uplink transmitting other data or control information from electronic device 902 to base station 904. Any suitable communication protocol or standard can be used, such as 3GPP LTE, 3GPP NR 5G, IEEE 802.11, IEEE 802.16, Bluetooth, etc. ™ To achieve wireless link 906.

[0080] Electronic device 902 includes at least one processor 980 and at least one memory 982. Memory 982 may be part of or form part of a computer-readable storage medium. Processor 980 may include any type of processor configured to execute processor-executable instructions (e.g., code) stored in memory 982, such as an application processor or a multi-core processor. Memory 982 may include any suitable type of data storage medium, such as volatile memory (e.g., random access memory (RAM)), non-volatile memory (e.g., flash memory), optical media, magnetic media (e.g., magnetic disk or magnetic tape), etc. In the context of this disclosure, memory 982 is implemented to store instructions 984, data 986, and other information of electronic device 902, and therefore, when configured as a computer-readable storage medium or part thereof, memory 982 does not include transient propagation signals or carrier waves.

[0081] Electronic device 902 may also include input / output port 990. I / O port 990 enables data exchange or interaction with other devices, networks, users, or components of the device.

[0082] The electronic device 902 may also include at least one signal processor (SP) 992 (e.g., such as a digital signal processor (DSP)). The signal processor 992 may function similarly to a processor and may be able to execute instructions and / or process information in conjunction with memory 982.

[0083] For communication purposes, electronic device 902 also includes a modem 994, a wireless transceiver 996, and an antenna (not shown). The wireless transceiver 996 uses radio frequency (RF) wireless signals to provide connectivity to a corresponding network and other electronic devices connected to those networks, and may include... Figure 8 The transceiver circuit 800. The wireless transceiver 996 can facilitate communication on any suitable type of wireless network, such as wireless local area network (WLAN), peer-to-peer (P2P) network, mesh network, cellular network, wireless wide area network (WWAN), navigation network (e.g., North American Global Positioning System (GPS) or another Global Navigation Satellite System (GNSS)) and / or wireless personal area network (WPAN).

[0084] Example

[0085] In addition to the various aspects described above, specific combinations of these aspects are also within the scope of this disclosure, some of which are detailed below:

[0086] Aspect 1: An electroacoustic device comprising: a piezoelectric layer; a surface acoustic wave (SAW) resonator disposed above the piezoelectric layer; a first non-piezoelectric region disposed adjacent to the piezoelectric layer; and an interdigital capacitor (IDC) electrically coupled to the SAW resonator and disposed above the first non-piezoelectric region.

[0087] Aspect 2: In the electroacoustic device according to aspect 1, any portion of the piezoelectric layer is not disposed between the IDC and the first non-piezoelectric region, such that the IDC is decoupled from the piezoelectric layer.

[0088] Aspect 3: The electroacoustic device according to aspect 1 or 2, wherein the first non-piezoelectric region is disposed in the cavity of the piezoelectric layer.

[0089] Aspect 4: The electroacoustic device according to aspect 3, wherein the cavity extends from the top surface of the piezoelectric layer to the bottom surface of the piezoelectric layer.

[0090] Aspect 5: An electroacoustic device according to any one of Aspects 1 to 4, wherein the top surface of the piezoelectric layer and the top surface of the first non-piezoelectric region are coplanar.

[0091] Aspect 6: An electroacoustic device according to any one of aspects 1 to 5, wherein the top surface of the first non-piezoelectric region is lower than the top surface of the piezoelectric layer.

[0092] Aspect 7: An electroacoustic device according to any one of Aspects 1 to 6, wherein the first non-piezoelectric region comprises a first dielectric material.

[0093] Aspect 8: The electroacoustic device according to aspect 7, wherein the first dielectric material comprises silicon dioxide (SiO2).

[0094] Aspect 9: The electroacoustic device according to any one of Aspects 1 to 8, the electroacoustic device further includes a second non-piezoelectric region disposed below the first non-piezoelectric region.

[0095] Aspect 10: The electroacoustic device according to aspect 9, wherein the first non-piezoelectric region comprises a first material, wherein the second non-piezoelectric region comprises a second material, and wherein the first material has a higher dielectric constant than the second material.

[0096] Aspect 11: An electroacoustic device according to any one of Aspects 1 to 10, wherein the SAW resonator is a thin-film SAW (TF-SAW) resonator, wherein the TF-SAW resonator includes a temperature compensation layer disposed below the first non-piezoelectric region, and wherein the temperature compensation layer includes silicon dioxide (SiO2).

[0097] Aspect 12: An electroacoustic device according to any one of Aspects 1 to 11, wherein the distance between the top of the finger in the SAW resonator and the piezoelectric layer is different from the distance between the top of the finger in the IDC and the first non-piezoelectric region.

[0098] Aspect 13: An electroacoustic device according to any one of aspects 1 to 12, comprising an array of fingers in the IDC aligned in a first direction, and comprising an array of fingers in the SAW resonator aligned in a second direction perpendicular to the first direction.

[0099] Aspect 14: A filter circuit comprising a plurality of resonators and a capacitor electrically coupled to the resonators in the plurality of resonators, wherein the capacitor and the resonators respectively comprise the IDC and the SAW resonator of the electroacoustic device according to any one of Aspects 1 to 13.

[0100] Aspect 15: A wireless device comprising an electroacoustic device according to any one of Aspects 1 to 14, the wireless device further comprising at least one of an antenna or a radio frequency (RF) circuit coupled to the electroacoustic device.

[0101] Aspect 16: A method of manufacturing an electroacoustic device, the method comprising: forming a first non-piezoelectric region adjacent to a piezoelectric layer; forming a SAW resonator over the piezoelectric layer; and forming an IDC over the first non-piezoelectric region.

[0102] Aspect 17: According to the method of aspect 16, forming the first non-piezoelectric region includes: forming a cavity in the piezoelectric layer; and depositing a first non-piezoelectric material in the cavity to form the first non-piezoelectric region.

[0103] Aspect 18: The method according to aspect 17, wherein forming the cavity includes removing a portion of the piezoelectric layer.

[0104] Aspect 19: The method according to aspect 18, wherein removing the portion of the piezoelectric layer includes etching the piezoelectric layer to form the cavity.

[0105] Aspect 20: The method according to any one of aspects 16 to 19, the method further comprising forming a second non-piezoelectric region adjacent to the piezoelectric layer, wherein forming the first non-piezoelectric region comprises forming the first non-piezoelectric region over the second non-piezoelectric region.

[0106] Aspect 21: According to the method of aspect 20, the first non-piezoelectric region comprises a first material, the second non-piezoelectric region comprises a second material, and the first material has a higher dielectric constant than the second material.

[0107] Additional Notes

[0108] The various operations of the methods described above can be performed by any suitable component capable of performing the corresponding function. This component may include various hardware and / or software components and / or modules.

[0109] As used herein, the term "determine" encompasses a wide variety of actions. For example, "determine" can include calculation, operation, processing, deduction, investigation, lookup (e.g., searching in a table, database, or other data structure), assertion, etc. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), etc. Additionally, "determine" can include parsing, selecting, picking, building, etc.

[0110] Within this disclosure, the term "exemplary" is used to mean "serving as an example, instance, or illustration." Any specific implementation or aspect described herein as "exemplary" is not necessarily to be construed as superior to or better than other aspects of this disclosure. Similarly, the term "aspect" does not require that all aspects of this disclosure include the features, advantages, or modes of operation discussed. The term "coupling" is used herein to refer to direct or indirect coupling between two objects. For example, if object A physically contacts object B, and object B contacts object C, objects A and C can still be considered coupled to each other, even if objects A and C are not in direct physical contact. For example, a first object can be coupled to a second object, even if the first object never has direct physical contact with the second object. The term "circuit" is used broadly and is intended to include hardware implementations of electronic devices and conductors that, when connected and configured, enable the performance of the functions described in this disclosure, without limitation on the type of electronic circuit.

[0111] The apparatus and methods described in the detailed description are illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively, "elements"). These elements may be implemented, for example, in hardware.

[0112] One or more of the components, steps, features, and / or functions illustrated herein may be rearranged and / or combined into a single component, step, feature, or function, or embodied in several components, steps, or functions. Additional elements, components, steps, and / or functions may also be added without departing from the features disclosed herein. The apparatus, devices, and / or components illustrated herein may be configured to perform one or more of the methods, features, or steps described herein.

[0113] It should be understood that the specific order or hierarchy of steps in the disclosed methods is an example of an exemplary process. It should be understood that the specific order or hierarchy of steps in these methods may be rearranged based on design preferences. The appended method claims present the elements of various steps in an exemplary order, but are not intended to limit them to the specific order or hierarchy presented, unless specifically stated herein.

[0114] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are to be consistent with the full scope of the claims, wherein references to elements in the singular form are not intended to mean “one and only one”, but rather “one or more”, unless specifically stated otherwise. The term “some” refers to one or more unless specifically stated otherwise. The phrase “at least one of” referring to the list of items means any combination of those items, including a single member. As an example, “at least one of a, b, or c” is intended to cover at least: a, b, c, ab, ac, bc, and abc, and any combination having multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c). All structural and functional equivalents of the elements throughout the various aspects described herein that are known to or will later be known to a person skilled in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is explicitly recited in the claims. No claim element should be construed in accordance with 35 USC § 112(f) unless it is expressly recited using the phrase “component for…” or, in the case of a method claim, using the phrase “step for…”.

[0115] It should be understood that the claims are not limited to the precise configurations and components illustrated above. Various modifications, variations, and alterations may be made to the arrangement, operation, and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. An electroacoustic device, the electroacoustic device comprising: piezoelectric layer; A surface acoustic wave (SAW) resonator, wherein the surface acoustic wave (SAW) resonator is disposed above the piezoelectric layer; A first non-piezoelectric region is disposed adjacent to the piezoelectric layer; and Interdigitated capacitors (IDCs) are electrically coupled to the SAW resonator and disposed above the first non-piezoelectric region.

2. The electroacoustic device according to claim 1, wherein no portion of the piezoelectric layer is disposed between the IDC and the first non-piezoelectric region, thereby decoupling the IDC from the piezoelectric layer.

3. The electroacoustic device according to claim 1, wherein the first non-piezoelectric region is disposed in the cavity of the piezoelectric layer.

4. The electroacoustic device according to claim 3, wherein the cavity extends from the top surface of the piezoelectric layer to the bottom surface of the piezoelectric layer.

5. The electroacoustic device according to claim 1, wherein the top surface of the piezoelectric layer and the top surface of the first non-piezoelectric region are coplanar.

6. The electroacoustic device according to claim 1, wherein the top surface of the first non-piezoelectric region is lower than the top surface of the piezoelectric layer.

7. The electroacoustic device according to claim 1, wherein the first non-piezoelectric region comprises a first dielectric material.

8. The electroacoustic device according to claim 7, wherein the first dielectric material comprises silicon dioxide (SiO2).

9. The electroacoustic device according to claim 1, wherein the electroacoustic device further comprises a second non-piezoelectric region disposed below the first non-piezoelectric region.

10. The electroacoustic device of claim 9, wherein the first non-piezoelectric region comprises a first material, wherein the second non-piezoelectric region comprises a second material, and wherein the first material has a higher dielectric constant than the second material.

11. The electroacoustic device according to claim 1, wherein the SAW resonator is a thin-film SAW (TF-SAW) resonator, wherein the TF-SAW resonator includes a temperature compensation layer disposed below the first non-piezoelectric region, and wherein the temperature compensation layer includes silicon dioxide (SiO2).

12. The electroacoustic device of claim 1, wherein the distance between the top of the finger in the SAW resonator and the piezoelectric layer is different from the distance between the top of the finger in the IDC and the first non-piezoelectric region.

13. The electroacoustic device of claim 1, comprising an array of fingers in the IDC aligned in a first direction, and comprising an array of fingers in the SAW resonator aligned in a second direction perpendicular to the first direction.

14. A filter circuit comprising a plurality of resonators and a capacitor electrically coupled to the resonators in the plurality of resonators, wherein the capacitor and the resonators respectively comprise the IDC and the SAW resonator of the electroacoustic device according to claim 1.

15. A wireless device comprising the electroacoustic device of claim 1, the wireless device further comprising at least one of an antenna or radio frequency (RF) circuitry coupled to the electroacoustic device.

16. A method for manufacturing an electroacoustic device, the method comprising: A first non-piezoelectric region is formed adjacent to the piezoelectric layer; A surface acoustic wave (SAW) resonator is formed above the piezoelectric layer; as well as An interdigitated capacitor (IDC) is formed above the first non-piezoelectric region.

17. The method of claim 16, wherein forming the first non-piezoelectric region comprises: A cavity is formed in the piezoelectric layer; as well as A first non-piezoelectric material is deposited in the cavity to form the first non-piezoelectric region.

18. The method of claim 17, wherein forming the cavity includes removing a portion of the piezoelectric layer.

19. The method of claim 18, wherein removing the portion of the piezoelectric layer comprises etching the piezoelectric layer to form the cavity.

20. The method of claim 16, further comprising forming a second non-piezoelectric region adjacent to the piezoelectric layer, wherein forming the first non-piezoelectric region includes forming the first non-piezoelectric region over the second non-piezoelectric region, wherein the first non-piezoelectric region comprises a first material, wherein the second non-piezoelectric region comprises a second material, and wherein the first material has a higher dielectric constant than the second material.

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