Surface acoustic wave electro-acoustic device for reduced lateral modes

Abstract

Aspects of the present disclosure relate to an electroacoustic device including a piezoelectric material (602) and an electrode structure (604) including a first busbar (622) and a second busbar (624) and electrode fingers (626) arranged in an interdigitated fashion and including a first plurality of fingers (626a) connected to the first busbar and a second plurality of fingers (626b) connected to the second busbar. The electrode structure further includes a first conductive structure (629a) disposed between each of the first plurality of fingers and between the first busbar and the second plurality of fingers. The electrode structure further includes a second conductive structure (629b) disposed between each of the second plurality of fingers and between the second busbar and the first plurality of fingers. The first and second conductive structures each have a height that is less than a height of the second plurality of fingers.

Description

[0001] Cross-references to other applications

[0002] This patent application claims the benefit of U.S. Patent Application Serial No. 17 / 302224, filed April 27, 2021, entitled “SURFACE ACOUSTIC WAVE ELECTROACOUSTIC DEVICE FOR REDUCED TRANSVERSAL MODES”, and also claims the benefit of U.S. Provisional Patent Application No. 63 / 017955, filed April 30, 2020, assigned to its assignee, and is expressly incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to surface acoustic wave (SAW) electroacoustic devices such as SAW resonators, and more specifically to interdigital transducer (IDT) electrode structures for electroacoustic devices that reduce transverse acoustic modes. Background Technology

[0004] Electronic devices include traditional computing devices such as desktop computers, laptops, tablets, smartphones, wearable devices such as smartwatches, internet servers, and so on. These diverse electronic devices provide human users with information, entertainment, social interaction, confidentiality, security, 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, broadcasting, etc. These systems are capable of supporting 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] Wireless transceivers used in these electronic devices typically include multiple radio frequency (RF) filters for filtering signals at specific frequencies or frequency ranges. In many applications, electroacoustic devices (e.g., "acoustic filters") are used 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 a speed with an amplitude significantly smaller than the propagation speed of electromagnetic waves. Generally, the amplitude of a wave's propagation speed is proportional to the wavelength of the wave. Therefore, after the electrical signal is converted into an acoustic signal, the wavelength of the acoustic signal wave is significantly smaller than the wavelength of the electrical signal wave. The smaller wavelength of the resulting sound signal allows for the use of smaller filter devices to perform filtering. This allows acoustic resonators to be used in electronic devices with size limitations, such as those listed above (e.g., particularly portable electronic devices such as cellular phones).

[0006] As the number of frequency bands used in wireless communication increases and the desired bandwidth of filters widens, the performance of acoustic filters becomes increasingly important for reducing losses and improving the overall performance of electronic devices. Therefore, there is a subsequent search for acoustic filters with improved performance. Summary of the Invention

[0007] In one aspect of this disclosure, an electroacoustic device is provided. The electroacoustic device includes a piezoelectric material. The electroacoustic device also includes an electrode structure. The electrode structure includes a first busbar and a second busbar. The electrode structure also includes electrode fingers arranged in an interdigitated manner and including a first plurality of fingers connected to the first busbar and a second plurality of fingers connected to the second busbar. The electrode structure also includes a first conductive structure disposed between each of the first plurality of fingers and between the first busbar and the second plurality of fingers. The first conductive structure has a height smaller than the height of the first plurality of fingers. The electrode structure also includes a second conductive structure disposed between each of the second plurality of fingers and between the second busbar and the first plurality of fingers. The second conductive structure has a height smaller than the height of the second plurality of fingers.

[0008] In another aspect of this disclosure, a method is provided for filtering electrical signals via an electroacoustic device comprising a piezoelectric material and an interdigital transducer. The method includes providing an electrical signal to terminals of the interdigital transducer. The method also includes reducing transverse acoustic modes via conductive structures respectively connected between respective buses and electrode fingers of the interdigital transducer. The height of the conductive structures is less than the height of the electrode fingers.

[0009] In another aspect of this disclosure, a method for forming an electroacoustic device is provided. The method includes forming a piezoelectric material layer. The method further includes forming an electrode structure on or over the piezoelectric material. Forming the electrode structure includes forming a first busbar and a second busbar. Forming the electrode structure also includes forming electrode fingers arranged in an interdigitated manner. Forming the electrode fingers includes forming a first plurality of fingers connected to the first busbar and forming a second plurality of fingers connected to the second busbar. Forming the electrode structure further includes forming a first conductive structure disposed between each of the first plurality of fingers. The first conductive structure has a height smaller than the height of the first plurality of fingers. Forming the electrode structure further includes forming a second conductive structure disposed between each of the second plurality of fingers. The second conductive structure has a height smaller than the height of the second plurality of fingers.

[0010] In another aspect of this disclosure, an electroacoustic device is provided. The electroacoustic device includes a piezoelectric material. The electroacoustic device also includes an electrode structure comprising a first busbar and a second busbar. The electrode structure further includes electrode fingers arranged in an interdigitated manner and connected to the first busbar or the second busbar. The electrode structure also includes means for controlling the acoustic velocity in a first region between the first busbar and the electrode fingers, and in a second region between the second busbar and the electrode fingers. The means for controlling the acoustic velocity has a height less than the height of the electrode fingers.

[0011] In another aspect of this disclosure, an electroacoustic device is provided. The electroacoustic device includes a piezoelectric material. The electroacoustic device also includes an electrode structure comprising electrode fingers arranged in an interdigitated manner, and including a first plurality of fingers and a second plurality of fingers. The electrode structure further includes a first conductive structure connected to and between each of the first plurality of fingers. The first conductive structure has a height smaller than the height of the first plurality of fingers. The electrode structure also includes a second conductive structure connected to and between each of the second plurality of fingers. The second conductive structure has a height smaller than the height of the second plurality of fingers.

[0012] In another aspect of this disclosure, an electrode structure is provided. The electrode structure includes a first busbar and a second busbar. The electrode structure also includes electrode fingers arranged in a forked manner, comprising a first plurality of fingers connected to the first busbar and a second plurality of fingers connected to the second busbar. The electrode structure further includes a first conductive structure disposed between the ends of the second plurality of fingers and the first busbar. The first conductive structure has a height smaller than the height of the first plurality of fingers. The electrode structure also includes a second conductive structure disposed between the ends of the first plurality of fingers and the second busbar. The second conductive structure has a height smaller than the height of the second plurality of fingers. Attached Figure Description

[0013] Figure 1A This is a perspective view of an example of an electroacoustic device.

[0014] Figure 1B yes Figure 1A A side view of an electroacoustic device.

[0015] Figure 2A This is a top view of an example of the electrode structure of an electroacoustic device.

[0016] Figure 2B This is a top view of another example of the electrode structure of an electroacoustic device.

[0017] Figure 3A This is a perspective view of another example of an electroacoustic device.

[0018] Figure 3B yes Figure 3A A side view of an electroacoustic device.

[0019] Figure 4 This is a diagram of a portion of the electrode structure of an electroacoustic device, aligned with a graph showing the sound velocity distribution in different regions of the electroacoustic device.

[0020] Figure 5A and Figure 5B This is a diagram illustrating an example of an electrode structure, which shows a reference. Figure 4 Examples of different implementations of the defined trap area.

[0021] Figure 6A This is a diagram illustrating an example of an electrode structure for an electroacoustic device that reduces transverse acoustic modes according to various aspects of this disclosure.

[0022] Figure 6B yes Figure 6A The electrode structure is shown in a side view along the cross section.

[0023] Figure 6C and Figure 6D Based on certain aspects of this disclosure Figure 6A and Figure 6BAn illustration of an example implementation of the electrode structure.

[0024] Figure 7A and Figure 7B Based on certain aspects of this disclosure Figure 6A and Figure 6B An illustration of an example implementation of the electrode structure.

[0025] Figure 8A It shows that it is aimed at Figure 6A A graph showing the relationship between the acoustic wave propagation angle and frequency in different regions of the electrode structure.

[0026] Figure 8B It shows including Figure 6A The relationship between the admittance value and frequency of the electroacoustic device and the corresponding slowness curve is compared with that of the electrode structure and the alternative electrode structure.

[0027] Figure 9 This is a flowchart illustrating an example of a method for forming an electroacoustic device according to certain aspects of this disclosure, the electroacoustic device comprising a piezoelectric material and Figure 6A Electrode structure.

[0028] Figure 10 It can include Figure 6A A schematic diagram of an electroacoustic filter circuit with an electrode structure.

[0029] Figure 11 It can be used in it Figure 10 A functional block diagram of at least a portion of a simplified example of a wireless transceiver circuit with a filter circuit.

[0030] Figure 12 It is a diagram of an environment including electronic devices, such as... Figure 11 A wireless transceiver with transceiver circuitry. Detailed Implementation

[0031] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of exemplary embodiments and not as representing the only embodiments in which the invention can be practiced. The term "exemplary" as used throughout the specification means "serving as an example, instance, or illustration" and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details used to provide a thorough understanding of the exemplary embodiments. In some instances, some devices are shown in block diagram form. Common elements in the following drawings may be identified using the same reference numerals.

[0032] Electroacoustic devices employing electrode structures on the surface of piezoelectric materials (such as surface acoustic wave (SAW) resonators) are designed to cover a wider frequency range (e.g., 500 MHz to 6 GHz), have higher bandwidth (e.g., up to 25%), and exhibit improved efficiency and performance. Typically, some SAW resonators are designed to allow sound waves to propagate through the piezoelectric material in a specific direction (e.g., a dominant acoustic mode). However, due to the properties of the specific piezoelectric material used and the way it is excited by the electrode structure, at least some undesirable acoustic modes may be generated in other directions. For example, transverse acoustic modes, transverse to the dominant (e.g., fundamental) acoustic mode, may be excited in the piezoelectric material. These transverse acoustic modes may be undesirable and have an adverse effect on filter performance (e.g., introducing ripples in the filter's passband). By adjusting the characteristics of the electrode structure, the sound velocity in individual transverse regions can be controlled in a manner that reduces transverse acoustic modes. The adjusted characteristics may depend on the type of piezoelectric material and other characteristics of the SAW resonator. Aspects of this disclosure relate to specific electrode structure configurations for reducing transverse acoustic modes. Specifically, the electrode structure configuration described herein includes the introduction of a conductive structure disposed between the busbar and the electrode fingers of the electrode structure. The conductive structure is connected to at least a portion of the electrode fingers and between at least a portion of the electrode fingers, and has a height less than the height of the electrode fingers to control the sound velocity in certain regions, thereby reducing lateral modes.

[0033] Figure 1A This is a perspective view of an example of an electroacoustic device 100. The electroacoustic device 100 can be configured as a SAW resonator or as part of a SAW resonator. In some descriptions herein, the 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. The electroacoustic device 100 includes an electrode structure 104 on the surface of a piezoelectric material 102, which may be referred to as an interdigital transducer (IDT). The electrode structure 104 generally includes a first comb-shaped electrode structure and a second comb-shaped electrode structure (conductive and generally metallic), having electrode fingers extending from two busbars toward each other, the electrode fingers being arranged in an interlocking manner between the two busbars (e.g., in an interdigital arrangement). An electrical signal excited in the electrode structure 104 (e.g., an applied AC voltage) 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 waves propagate primarily in a direction perpendicular to the direction of the fingers (e.g., parallel to the generatrix).

[0034] Figure 1B yes Figure 1A The electroacoustic device 100 along Figure 1A The diagram shows a side view of section 107. The electroacoustic device 100 is shown as a simplified layer stack including piezoelectric material 102, with electrode structures 104 disposed on the piezoelectric material 102. The electrode structures 104 are conductive and generally formed of a metallic material. The piezoelectric material can be formed of a variety of materials, such as quartz, lithium tantalate (LiTaO3), lithium niobate (LiNbO3), doped variants of these materials, or other piezoelectric materials. It should be understood that more complex layer stacks including various material layers can be present within the stack. For example, optionally, a temperature compensation layer 108, indicated by dashed lines, can be disposed above the electrode structures 104. The piezoelectric material 102 can extend to have multiple interconnected electrode structures disposed thereon to form a multi-resonator filter or provide multiple filters. Although not shown, a cap layer can be provided above the electrode structures 104 when provided as an integrated circuit component. The cap layer is applied such that a cavity is formed between the electrode structures 104 and the lower surface of the cap layer. It may also include electrical vias or bumps that allow components to be electrically connected to connectors on a substrate (e.g., via flip chips or other technologies).

[0035] Figure 2A This is a top view of an example of the electrode structure 204a of the electroacoustic device 100. The electrode structure 204a has an IDT 205, which includes a first busbar 222 (e.g., a first conductive segment or rail) and a second busbar 224 (e.g., a second conductive segment or rail). The first busbar 222 is electrically connected to a first terminal 220, and the second busbar 224 is spaced apart from the first busbar 222 and connected 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.

[0036] Along the direction of the generatrix, there exists an overlapping region including a central region in which a portion of one finger overlaps with a portion of an adjacent finger, as shown in central region 225. This overlapping central region 225 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. This pitch can be indicated in various ways. For example, in some aspects, the pitch may correspond to the dimension of the distance between the fingers in central region 225. This distance may be defined, for example, the distance between the center points of each finger (and when the fingers have a uniform thickness, it can typically be 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 self-resonant (also called "master resonance") frequency of the electrode structure 204a. This frequency is determined at least in part by the pitch of the IDT 205 and other characteristics of the electroacoustic device 100.

[0037] An IDT 205 is arranged between two reflectors 228 that reflect sound waves back towards the IDT 205, serving to convert the sound waves into electrical signals via the IDT 205 in the illustrated configuration and to prevent loss (e.g., confining and preventing escaped sound waves). Each reflector 228 has two buses and a grating structure with conductive fingers connected to the two buses. The pitch of the reflectors can be similar to or the same as the pitch of the IDT 205 to reflect sound waves in the resonant frequency range. However, many configurations are possible.

[0038] 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.

[0039] Multiple electrode structures are possible. Figure 2A A single-port configuration is generally shown. Other two-port configurations are also possible. For example, electrode structure 204a may have an input IDT 205, in which each terminal 220 and 230 serves as an input. In this case, adjacent output IDTs (not shown) may be provided, positioned between reflectors 228 and adjacent to the input IDT 205, to convert acoustic waves propagating in the piezoelectric material 102 into electrical signals that will be provided at the output terminals of the output IDTs.

[0040] Figure 2BThis is a top view of another example of the electrode structure 204b of the electroacoustic device 100. In this case, a dual-mode SAW (DMS) electrode structure 204b is shown, which is a structure capable of inducing multiple resonances. The electrode structure 204b includes multiple IDTs and a reflector 228 connected as shown. The electrode structure 204b is provided to illustrate that the principles described herein can be applied to, among other things... Figure 2A and Figure 2B Various electrode structures of electrode structures 204a and 204b.

[0041] It should be understood that although a certain number of fingers 226 are shown, the actual number of fingers, as well as the length and width of the fingers 226 and the busbar, may differ in actual implementations. These parameters depend on the specific application of the filter and the desired frequency. Furthermore, the SAW filter may include multiple interconnected electrode structures, each including multiple IDTs to achieve the desired passband (e.g., multiple interconnected resonators or IDTs to form the desired filter transfer function).

[0042] Figure 3A This is a perspective view of another example of the electroacoustic device 300. The electroacoustic device 300 (e.g., it can be configured as a SAW resonator or part of a SAW resonator) is similar to... Figure 1A Electroacoustic device 100, but with a different layer stack. Specifically, electroacoustic device 300 includes a thin piezoelectric material 302 disposed 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). Based on the type of piezoelectric material 302 used (e.g., typically having a higher coupling factor than electroacoustic device 100 of FIG. 1) and the controlled thickness of piezoelectric material 302, the specific acoustic wave modes excited can be... Figure 1A The acoustic wave mode in the electroacoustic device 100 is slightly different. Based on the design (layer thickness and material selection, etc.), it differs from... Figure 1A Compared to the electroacoustic device 100, the electroacoustic device 300 can have a higher Q factor. For example, the piezoelectric material 302 can be lithium tantalate (LiTaO3) or some doped variant. Another example of the piezoelectric material 302 in Figure 3 could be lithium niobate (LiNbO3). Typically, the substrate 310 can be much thicker than the piezoelectric material 302 (e.g., as an example, possibly about 50 to 100 times thicker, or more). The substrate 310 may include other layers (or other layers may be included between the substrate 310 and the piezoelectric material 302).

[0043] Figure 3B yes Figure 3A A side view of the electroacoustic device 300. Figure 3A An exemplary layer stack is shown (along section 307). Figure 3B In the example shown, substrate 310 may include sublayers such as substrate sublayer 310-1 (e.g., silicon), which may have higher resistance (e.g., high resistivity layers relative to other layers). Substrate 310 may also include a trap-rich layer 310-2 (e.g., polycrystalline silicon). Substrate 310 may also include a compensation layer (e.g., silicon dioxide (SiO2) or other 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 of a specific thickness is disposed on substrate 310 to provide a specific acoustic mode (e.g., with...). Figure 1A Compared to the electroacoustic device 100, the thickness of the piezoelectric material 102 in the electroacoustic device 100 may not be a critical design parameter exceeding a certain thickness, and with Figure 3A and Figure 3B The piezoelectric material 302 of the electroacoustic device 300 can be thicker than usual. The electrode structure 304 is positioned above the piezoelectric material 302. In some aspects, one or more layers (e.g., a thin passivation layer) (not shown) may be present above the electrode structure 304.

[0044] Based on the type, thickness, and overall stack of piezoelectric materials, the coupling to electrode structure 304, and the sound velocity within the piezoelectric material in different regions of electrode structure 304, the effects vary between different types of electroacoustic devices (such as...). Figure 1A Electroacoustic devices 100 and Figure 3A and Figure 3B The electroacoustic devices (300 and above) can be different.

[0045] about Figure 1A and Figure 3A For electroacoustic devices 100 and 300, one source of potential loss that is expected to be reduced is stray acoustic wave modes that may include transverse acoustic modes. These transverse acoustic wave modes can cause undesirable ripples in the passband of the filter. Typically, electroacoustic devices are designed to confine or direct sound waves in a central region 225 (e.g., Figure 2AThe effective area shown is used to prevent entry into the main body (e.g., in the z-direction perpendicular to the surface) or lateral radiation. The limitation of acoustic waves can lead to the generation of a series of lateral acoustic modes (e.g., generally in a direction toward the generatrix and more parallel to the fingers 226). Specifically, the excited acoustic waves propagate perpendicular to the fingers 226, but also at certain angles relative to the main propagation direction, which can correspond to various lateral acoustic modes. Reducing these lateral acoustic modes is desirable because they cause sharp, deep dips in the filter passband when the corresponding electroacoustic device tracks are electrically connected.

[0046] Figure 4 This is a diagram of a portion of the electrode structure 404 of an electroacoustic device, which is aligned with a graph showing the sound velocity distribution in different regions of the electroacoustic device. Figure 4 Electrode structure 404 shows a portion of IDT 405, which is similar to reference DT 405. Figure 2A The described IDT has a first busbar 422, a second busbar 424, and interdigitated fingers 426. Since the angular and frequency positions of the transverse acoustic modes depend on the directional acoustic velocity, in one respect, the transverse velocity distribution within the acoustic track can be designed to reduce transverse acoustic modes and promote the excitation of the dominant or fundamental mode. Specifically, the electrode structure 404 (and possibly other layers) can be adjusted in different regions of the electrode structure 404 to modulate the transverse velocity distribution within the acoustic track, thereby reducing transverse acoustic modes (e.g., effectively forming transverse acoustic waveguides). In some respects, the velocity of sound can correspond to the velocity of sound of the fundamental mode of the electroacoustic device, although in other respects this velocity can be more generally understood as capturing different modes or being associated with different modes.

[0047] Figure 4 Different regions of electrode structure 404 are shown, and these regions can be designed or structurally modified to adjust the lateral velocity distribution. (See also: Regarding...) Figure 2A As described, the central region 425 (or effective track region or aperture) is defined where the intersecting fingers overlap (e.g., in a direction parallel to the generatrix) and is where the main pattern or basic pattern is generally intended and designed to propagate perpendicular to the fingers 426.

[0048] On one hand, a blocking region 429 (e.g., a gap region) is defined outside a central region 425, which includes the area between the first busbar 422 and the fingers 426a connected to the opposing second busbar 424. More specifically, the blocking region 429 includes a first blocking region 429a and a second blocking region 429b. The first blocking region 429a is defined between the first busbar 422 and the unconnected ends of the first set of fingers 426a connected to the second busbar 424. The second blocking region 429b is defined between the second busbar 424 and the unconnected ends of the second set of fingers 426b connected to the first busbar 422. The blocking region 429 may sometimes correspond to or be referred to as a lateral gap, which is included in the IDT to separate metal structures with different potentials (i.e., to separate fingers connected to opposing buses when the buses have different potentials).

[0049] To adjust the lateral velocity distribution, the number of fingers per wavelength within the blocking region 429 (e.g., one finger instead of the two fingers shown in the central region 425), and the distance or size of the blocking region 429 (and / or by adjusting other characteristics within the blocking region 429) are chosen such that a higher sound wave velocity exists, particularly higher than that in the central region 425. The graph 440 to the right of the electrode structure 404 shows the relative velocity of each region of the electrode structure 404, where the y-axis represents and is aligned with the direction along which the different regions of the electrode structure 404 extend along the fingers 426. As shown by line 450 (see the dashed section), the sound velocity along the x-axis is higher in the blocking region 429 compared to the sound velocity in the central region 425 (e.g., the effective track). Generally, a relatively higher wave velocity can be a hindrance to sound waves because sound waves may tend to propagate more easily where the velocity is lower. The distance / width of the blocking region 429 (e.g., at least 2-3 wavelengths for some applications) can be wider than the distance / width required to adequately separate metal structures at different potentials, providing sufficient blocking and preventing acoustic waves from coupling into the external region.

[0050] In addition to the blocking region 429, other regions referred to as trap regions 427 are provided at either outer boundary (e.g., defined at each end) of the central region 425 where the fingers 426 overlap. Specifically, a first trap region 427a is positioned near or at a first end (e.g., a boundary) of the central region 425 (e.g., the effective region), and between the first blocking region 429a and the central region 425 (e.g., in the region of the fingers 426 near the end of the first set of fingers 426a connected to the second busbar 424, wherein this region is away from the second busbar 424). The second trap region 427b is positioned near or at the second end of the central region 425 (opposite to the first end), and between the second blocking region 429b and the central region 425 (e.g., in the region of the ends of the fingers facing the second set of fingers 426b, which are connected to the first busbar 422, wherein this region is away from the first busbar 422). The trap region 427 may correspond to the outer edge or outer region of the central region 425. Different structural characteristics from those of the central region 425 are provided in the trap region 427 to create a region of the electroacoustic device aligned with the trap region 427, which has a reduced sound wave velocity, particularly lower than the sound wave velocity in the region defined by the central region 425. Such structural characteristics may include widening the electrode fingers 426 in the trap region 427, or increasing the height of the electrode fingers 426 in the trap region 427, but many implementations are possible. Generally, sound waves may tend to propagate more easily at lower velocities. Therefore, the trap region 427 with a low acoustic velocity can provide a way to shape the lateral amplitude distribution of the basic acoustic mode.

[0051] As a result of the design and selection of the dimensions of the blocking region 429, the trapping region 427, and the central region 425, the amplitude of the fundamental acoustic mode in the lateral direction (e.g., in the direction of the finger 426) can conform to a rectangular distribution indicated by line 444 of graph 440. The rectangular distribution caused by the different acoustic velocities in the different regions corresponds to modes where undesired lateral modes are suppressed. Line 442 in graph 440 corresponds to the fundamental mode amplitude in the lateral direction when there is no trapping region that could cause undesired lateral modes. Line 446 in graph 440 corresponds to the fundamental mode amplitude in the lateral direction when the trapping region 427 is not deep enough (e.g., the acoustic waves are not sufficiently slowed down in this region). Although improved, undesired lateral modes may continue to affect performance. Line 448 in graph 440 corresponds to the fundamental mode amplitude in the lateral direction when the trapping region 427 is too deep. This can also lead to undesired lateral acoustic modes. By adjusting the characteristics of the blocking region 429 and the trapping region 427, the amplitude of the basic mode in the lateral direction can be adjusted to conform to the rectangular distribution indicated by line 444, and the lateral mode can be effectively suppressed. The technique used to provide the blocking region 429 and the trapping region 427 in this configuration is sometimes referred to as the piston mode.

[0052] Figure 5A and Figure 5B These are illustrations of examples of electrode structures 504a and 504b, showing reference numerals. Figure 4 Examples of different implementations of the defined trap regions 527-1 and 527-2. The blocking region 529 is indicated but not specifically shown or drawn to scale. Instead, electrode structures 504a and 504b are provided to illustrate trap region 527-1. Figure 5A ) and 527-2 Figure 5B The implementation method of ). For example, in Figure 5A In the electrode structure 504a, the trap region 527-1 is shown as a portion 509 of the electrode structure 504a, which has an increased thickness relative to the rest of the effective region. A side view along section 531 is shown on the right. The increased height can result in a slower sound velocity in the trap region 527-1. In another embodiment, as... Figure 5B As shown in electrode structure 504b, the electrode structure 504b within the trap region 527-2 has a wider width compared to the effective region. This wider width can result in a slower sound velocity within the trap region 527-2. In some embodiments, the trap region 527-2 may have a wider width compared to the effective region and, as shown in the figure... Figure 5AThe increased height (e.g., thickness) is shown. Therefore, any techniques described herein for trap region 527-2 can be combined. In other embodiments, other materials (e.g., a dielectric material layer) may be positioned in trap region 427. Figure 4 Above, to reduce the sound velocity in trap region 427 (e.g., or other types of mass load). Furthermore, one or more trimming operations can be adjusted or have a structural effect in each region, such that the relative sound velocity in trap region 427 is reduced relative to central region 425. Other embodiments using different techniques may also be employed, such that the structural characteristics in trap region 427 are adjusted and differ from those in central region 425, resulting in a reduced sound velocity in trap region 427.

[0053] In some electroacoustic device designs, the blocking region 429 can be a parameter sufficient to be adjusted to create a desired transverse sound velocity distribution to work in conjunction with the trapping region 427 to suppress transverse acoustic modes (e.g., achieving relatively higher sound velocities than in the effective region). However, for some other electroacoustic devices that wish to use different materials, configuring the size of the blocking region 429 may not create a transverse mode acoustic distribution that results in sound velocities in the blocking region 429 being high enough to create the desired transverse velocity distribution. For example, Figure 3A and Figure 3B A thin-film electroacoustic device 300 is shown. In some embodiments, the piezoelectric material 302 in this electroacoustic device 300 may be formed of lithium tantalate (LiTaO3). This is based on the coupling factor (and can also be partly due to the specific layer stacking and thickness of the lithium tantalate, such as for...) Figure 3A and Figure 3B As shown in the thin film type, the sound velocity distribution of lithium tantalate can differ from other systems. For example, for lithium tantalate-based devices, the velocity difference between the central region 425 and the blocking region 429 may be low, so lateral modes may not be easily confined across the entire stopband of the electroacoustic device 300. Furthermore, for lithium tantalate-based electroacoustic devices, in the central region 425, the increased frequency may correspond to an angle increasing from the propagation direction of the main sound wave (e.g., sometimes referred to as "convex slowness"). However, for lithium tantalate-based systems, in the blocking region 429, the mode frequency decreases with increasing propagation angle ("concave slowness" in the blocking region 429). Concave slowness is attractive to sound waves and can create stray modes. Therefore, having concave slowness in the blocking region 429 can lead to the excitation of undesirable modes within the blocking region 429. Therefore, it is desirable to provide a structure that achieves convex slowness in the blocking region 429 to reduce unwanted modes in the blocking region 429 and to provide a desired higher sound velocity within the blocking region 429.

[0054] Some techniques for addressing these problems with such electroacoustic devices may be difficult to implement with high metallization ratios and high metal heights (and due to other manufacturing difficulties of this solution), and may increase ohmic losses. Furthermore, for certain configurations, such as when using reference... Figure 3A When referring to the lithium tantalate-based device, as shown in the reference Figure 4 The blocking region 429 (e.g., one strip for each wavelength) can result in a slowing effect. The aspects of this disclosure described herein relate to embodiments for the blocking region 429 that suppress lateral modes while being easier to manufacture and design. These techniques can be applied to a wide variety of electroacoustic devices, but may offer unique advantages for thin-film electroacoustic devices using lithium tantalate.

[0055] Figure 6A This is an illustration of an example electrode structure 604 for an electroacoustic device (e.g., a SAW resonator) that reduces transverse acoustic modes according to various aspects of this disclosure. The electrode structure 604 may be disposed on or above (or arranged relative to) a piezoelectric material 602 such that electroacoustic coupling exists between the piezoelectric material 602 and the electrode structure 604. The electrode structure 604 (which may be in the form of or include an IDT 605) includes a first busbar 622 and a second busbar 624. In some aspects, the first busbar 622 and the second busbar 624 may be more generally referred to as a conductive connection structure. In some aspects, the first busbar 622 and the second busbar 624 extend in a certain direction and are parallel or parallel to each other (although some difference in the angle between the busbars is possible).

[0056] The electrode structure 604 also includes electrode fingers 626, which are arranged in an interdigitated manner and connected to a first busbar 622 or a second busbar 624. Specifically, the electrode fingers 626 include a first plurality of fingers 626a, which are connected to the first busbar 622 and extend toward the second busbar 624. Furthermore, the electrode fingers 626 include a plurality of second fingers 626b, which are connected to the second busbar 624 and extend toward the first busbar 622. The electrode fingers 626 have a pitch 652. Similar to that described above with reference to FIG2 2, in some aspects, the pitch 652 may correspond to the periodicity of the electrode fingers 626. In some aspects, the pitch 652 may be indicated by the distance between the centers of adjacent electrode fingers 626. When the electrode fingers 626 generally have the same width, this distance may also be defined by the distance between the left edges (or right edges) of adjacent electrode fingers 626. Furthermore, in some aspects where the electrode fingers 626 are not uniformly distributed, the pitch 652 can be indicated by the average distance between the centers of adjacent electrode fingers 626. Other ways of measuring or indicating the pitch 652 are also possible. In some aspects, the electrode fingers 626 extend in a direction orthogonal to the directions of the first generatrix 622 and the second generatrix 624 (although some other angles are also possible).

[0057] Electrode structure 604 includes a first conductive structure 629a disposed between each of the first plurality of fingers 626a. In some aspects, the first conductive structure 629a is connected to each of the first plurality of fingers. The height of the first conductive structure 629a is less than the height of the first plurality of fingers 626a. This is in Figure 6B As shown in the image.

[0058] Figure 6B yes Figure 6A The electrode structure 604 is shown in a side view along section 654. As shown, the height of the first conductive structure 629a is less than the height of the first plurality of electrode fingers 626a.

[0059] The first conductive structure 629a is disposed between the first busbar 622 and the second plurality of electrode fingers 626b (e.g., in reference to...). Figure 4 In the first blocking region 429a described in A). A gap exists between the first conductive structure 629a and the second plurality of electrode fingers 626b in a direction extending along the second plurality of electrode fingers 626b. In some aspects, the first conductive structure 629a is connected to the first busbar 622. However, in some embodiments, the first conductive structure 629b may not be connected to the first busbar 622 (e.g., a gap exists between the first busbar 622 and one or more portions of the first conductive structure 629a).

[0060] Electrode structure 604 includes a second conductive structure 629b disposed between each of the second plurality of fingers 626b. In some aspects, the second conductive structure 629b is connected to each of the second plurality of fingers. The height of the second conductive structure 629b is smaller than the height of the second plurality of fingers 626b (e.g., similar to the height of the second plurality of fingers 626b). Figure 6B (As shown in the side view shown). The second conductive structure 629b is disposed between the second busbar 624 and the first plurality of electrode fingers 626a (e.g., in reference). Figure 4 In the second blocking region 429b described in A). A gap exists between the second conductive structure 629b and the first plurality of electrode fingers 626a in the direction extending along the first plurality of electrode fingers 626a. In some aspects, the second conductive structure 629b is connected to the second busbar 624. However, in some embodiments, the second conductive structure 629b may not be connected to the second busbar 624 (e.g., a gap exists between one or more portions of the second busbar 624 and the second conductive structure 629b). The first conductive structure 629a and the second conductive structure 629b may be collectively referred to as conductive structure 629. In some aspects, conductive structure 629 extends in the same direction as the first busbar 622 and the second busbar 624.

[0061] The height of the conductive structure 629 can vary depending on the application and the height of the electrode fingers 626, but is generally significantly lower than the height of the electrode fingers 626. Various heights are possible. As just one example, the height of the conductive structure 629 can be 5 nm–20 nm relative to the 150 nm height of the electrode fingers 626. Typically, some reflection from the electrode fingers 626 should be present. In other words, if the height of the conductive structure 629 is close to the heights of the busbars 622 and 624, the conductive structure 629 will be functionally incorporated into the busbars. In another example, the height (e.g., thickness) of the conductive structure 629 is between a few nanometers and tens of nanometers. Other exemplary ranges can be between 10 nm and 25 nm, although higher is also possible. In one example, the height of the conductive structure 629 is at least less than half the height of the electrode fingers 626. In another example, for the operating frequency of the electroacoustic device, the height of the conductive structure 629 is less than ten to fifteen percent of the wavelength.

[0062] In some aspects, the conductive structure 629 includes different conductive portions between each of the respective fingers. For example, the first conductive structure 629a may include multiple conductive portions between each of the first plurality of fingers 626a.

[0063] As shown in the figure, and similar to the reference. Figure 4 As described, the electrode fingers 626 have a central region 625, which may correspond to or include an effective region (also referred to as a track or aperture). In this region, a first plurality of fingers 626a and a second plurality of fingers 626b overlap in the direction in which the first generatrix 622 and the second generatrix 624 extend. A first trap region 627a and a second trap region 627b are collectively referred to as trap region 627, which is defined on the boundary of the central region 625 (see also reference). Figure 4 (Description of the described trap region 427). In some aspects, the first trap region 627a may be positioned in a region of the electrode fingers 626 aligned with the portion facing or located at the end of a second plurality of fingers 626b, the end of which is close to the first conductive structure 629a (wherein a gap exists between the first conductive structure 629a and the second plurality of fingers 626b). Correspondingly, the second trap region 627b may be positioned in a region of the electrode fingers 626 aligned with the portion facing the end of the first plurality of fingers 626a, the end of which is close to the second conductive structure 629b (wherein a gap exists between the second conductive structure 629b and the first plurality of fingers 626a). Referring above... Figure 4 , Figure 5A and Figure 5B The structural characteristics of the electroacoustic device differ relative to the central region 625 in the first trap region 427a and the second trap region 627b. For example, the structural characteristics may correspond to a portion of the electrode finger 626 that has an increased width or increased height within the first and second trap regions 627, or as referenced above. Figure 4 , Figure 5A and Figure 5B Any other characteristics mentioned above. Specifically, this structural characteristic results in a lower sound velocity in the region defined by the trap region 627 compared to the sound velocity in the central region 625 (and also lower than the blocking region including the conductive structure 629). In some aspects, the dimension of the trap region 627 in the direction in which the electrode fingers 626 extend can be between half the pitch 652 of the electrode fingers 626 and twice the pitch of the electrode fingers 626 (although the amount can vary based on the application).

[0064] As described above, conductive structure 629 corresponds to the reference as shown in the figure. Figure 4 The implementation of the blocking region 429. The conductive structure 629 is configured such that the sound velocity in the region of the conductive structure 629 is higher than that in the central region 625. Furthermore, the height of the conductive structure 629 can be adjusted to achieve a specific lateral velocity distribution to better suppress lateral acoustic modes (e.g., for a specific piezoelectric material 602 and layer stack for an electroacoustic device, achieving the same effect as...). Figure 4 The line 444 in the diagram shows a distribution similar to the rectangular distribution.

[0065] The acoustic velocity in the region of the conductive structure 629 is maintained higher than that in the central region 625 to provide effective blocking. (See above reference.) Figure 4 The difference in transverse acoustic velocity between the regions (combined with trap region 627) suppresses transverse acoustic modes. Furthermore, the conductive structure 629 can provide a convexity slowdown within its region, which is desirable for reducing acoustic modes excited in that region (particularly for certain piezoelectric materials such as lithium tantalate). Additionally, the manufacturability of the conductive structure 629 can be significantly improved compared to other embodiments (e.g., the same process used to increase the thickness in trap region 627 can be used to deposit a metallic conductive structure 629 with a specific height, although many fabrication techniques are possible). Furthermore, uniform metallization of the conductive structure 629 can reduce ohmic losses. Moreover, the gap between the conductive structure 629 and the unconnected fingers 626 can be kept sufficiently large to avoid peaks in the electric field strength, thereby increasing power endurance.

[0066] The dimension of the conductive structure 629 extending along the direction of the electrode fingers 626 can also be made smaller compared to certain other embodiments (e.g., for another structure or for increasing the size of the blocking region 429 to provide the desired sound velocity). In some respects, the dimension can be between 1.25 times and 4 times the wavelength for the operating frequency of the electroacoustic device. As an example, 125 nm may be sufficient for this dimension (e.g., length). Other dimensions are possible. Having a smaller blocking region, or in other words, using the conductive structure 629, can allow for savings in chip area. This is particularly valuable for embodiments involving cascaded tracks with multiple blocking regions and can allow for smaller chip sizes.

[0067] The first busbar 622, the second busbar 624, the conductive structure 629, and the electrode fingers 626 can generally be metallic or made of some other conductive material. In some respects, they can be formed from at least some of the same materials and can be implemented using a variety of different metal layer stacks.

[0068] Figure 6C and Figure 6D yes Figure 6A and Figure 6B An example illustration of an embodiment of electrode structure 604. Figure 6C and Figure 6DElectrode structure 604c shows a configuration where conductive structure 629 is not connected to electrode fingers 626 (e.g., a gap exists between portions of electrode fingers 626 and conductive structure 629 in the direction extending along the busbar). While in many embodiments conductive structure 629 is connected to electrode fingers 626, electrode structure 604c shows an alternative configuration. In this case, a first conductive structure 629a is disposed between a first busbar 622 and a plurality of fingers 626b, wherein the first conductive structure 629a has a height less than the height of the first plurality of fingers 626a. A second conductive structure 629b is disposed between a second busbar 624 and the first plurality of fingers 626a, wherein the second conductive structure 629b has a height less than the height of the second plurality of fingers 626b. Furthermore, as described above, although conductive structure 629 is shown as connected to buses 622 and 624, in a configuration based on... Figure 6C and Figure 6D In some configurations of the electrode structure 604c, gaps may exist between the busbar 622 and the conductive structure 629, as well as between the busbar 624 and the conductive structure 629.

[0069] Figure 7A and Figure 7B yes Figure 6A and 6B A schematic diagram illustrating an example of an embodiment of the electrode structure 604. Figure 7A and Figure 7B The electrode structure of 704 is similar to Figure 6A and Figure 6B The electrode structure 604 is shown, but a different implementation for the trap region 727 is illustrated. The trap region 727 is implemented with an electrode portion that is wider than the central region 725 (see reference above). Figure 5B (As described above). The trap region 727 can be implemented in various different ways.

[0070] Figure 8A It shows that it is aimed at Figure 6A The relationship between the propagation angle and frequency in different regions of electrode structure 604 is shown in graph 800a. On the y-axis, the indicator k with a value of zero... y Corresponding to the main propagation direction, where the increased k yThe value corresponds to an increased propagation angle (e.g., it may correspond to a lateral acoustic mode). The x-direction represents the frequency. The curve represented by graph 700 is sometimes referred to as the slowness curve. Line 862 corresponds to the curve for the central region 625, sometimes referred to as the track. Line 864 corresponds to the curve for the conductive structure 629. Line 866 corresponds to the curve for the busbars 622 and 624. Line 868 corresponds to the curve for an implementation using a gap instead of the conductive structure 629. Line 864 shows that the slowness curve for the conductive structure 629 can correspond to a convex slowness, which is necessary to suppress acoustic modes that may generate in the blocking region. Furthermore, the rate difference between the central region 625 and the region of the conductive structure 629 increases.

[0071] Figure 8B It shows including Figure 6A The relationship between the admittance and frequency of the electroacoustic device and the corresponding slowness curve is shown in Figure 800b, comparing the electrode structure 604 with that of the electroacoustic device using an alternative electrode structure. The top portion includes... Figure 8A The slow-motion curve includes curve 862 for the central region 625, curve 864 for the conductive structure 629, and curve 866 for the busbars 622 and 624. The bottom portion of the graph includes line 872, which corresponds to the use of... Figure 6A The electrode structure 604 represents the admittance of the electroacoustic device versus frequency. Line 874 corresponds to the admittance of the electroacoustic device versus frequency, which does not include the conductive structure 629, but only includes a gap extending in the blocking region 429. As shown, line 874 includes multiple significant ripples caused by transverse acoustic modes that degrade performance. Line 872, corresponding to the electrode structure 604 of Figure 6, includes significantly fewer ripples as shown, indicating the effectiveness of suppressing transverse acoustic modes.

[0072] Exemplary Operation

[0073] Figure 9 This is a flowchart illustrating an example of a method 900 for forming an electroacoustic device according to certain aspects of this disclosure, the electroacoustic device comprising a piezoelectric material 602 ( Figure 6A )and Figure 6A Electrode structure 604. Method 900 is described in the form of a set of blocks specifying operable operations. However, the operations are not necessarily limited to... Figure 9The order shown or described herein may vary, as operations may be performed in an alternative order or in a fully or partially overlapping manner. Furthermore, more, fewer, and / or different operations may be performed to execute method 900 or alternative methods. At block 902, method 900 includes forming a piezoelectric material layer 602. At block 904, method 900 further includes forming an electrode structure 604 on or over the piezoelectric material 602. The electrode structure 604 forming block 904 includes forming a first busbar 622 and a second busbar 624 at block 906. The electrode structure forming block 904 also includes forming electrode fingers 626 arranged in an interdigitated manner at block 908, wherein forming the electrode fingers 626 includes forming a first plurality of fingers 626a connected to the first busbar 622 and forming a second plurality of fingers 626b connected to the second busbar 624. The electrode structure forming frame 904 further includes a first conductive structure 629a formed at frame 910. The first conductive structure 629a is disposed between each of the first plurality of fingers 626a, and the first conductive structure 629a has a height smaller than the height of the first plurality of fingers 626a. The electrode structure forming frame 904 further includes a second conductive structure 629b formed at frame 912. The second conductive structure 629b is disposed between each of the second plurality of fingers 626b, and the second conductive structure 629b has a height smaller than the height of the second plurality of fingers 626b.

[0074] As described above, the electrode finger 626 has a central region 625, and the central region 625 has a first trap region 627a and a second trap region 627b respectively located on the boundary of the central region 625. In some aspects, the method 900 may further include at block 914 adjusting or forming structural characteristics of the electroacoustic device in the first and second trap regions 627 to reduce the speed of sound.

[0075] In some respects, reference Figure 6A A method for filtering electrical signals via an electroacoustic device including a piezoelectric material 602 and an interdigital transducer 605 can be provided. The method includes providing an electrical signal to terminals of the interdigital transducer 605. The method also includes reducing transverse acoustic modes via a conductive structure 629 respectively connected between a corresponding busbar (622 or 624) of the interdigital transducer 605 and an electrode finger 626, wherein the height of the conductive structure 629 is less than the height of the electrode finger 626.

[0076] have Figure 6A Electroacoustic devices with electrode structure 604 can be used in a variety of applications.

[0077] Figure 10 It can include Figure 6AA schematic diagram of an electroacoustic filter circuit 1000 with electrode structure 604 is provided. The filter circuit 1000 provides an example of the use of electrode structure 604. The filter circuit 1000 includes an input terminal 1002 and an output terminal 1014. A ladder network of SAW resonators is provided between the input terminal 1002 and the output terminal 1014. The filter circuit 1000 includes a first SAW resonator 1004, a second SAW resonator 1006, and a third SAW resonator 1008, all of which are electrically connected in series between the input terminal 1002 and the output terminal 1014. A fourth SAW resonator 1010 (e.g., a shunt resonator) has a first terminal connected between the first SAW resonator 1004 and the second SAW resonator 1006, and a second terminal connected to ground potential. A fifth SAW resonator 1012 (e.g., a shunt resonator) has a first terminal connected between the second SAW resonator 1006 and the third SAW resonator 1008, and a second terminal connected to ground potential. The electroacoustic filter circuit 1000 can, for example, be a bandpass circuit with a passband having a selected frequency range (e.g., on the order of 100 MHz and 3.5 GHz). Although Figure 10 An example of a ladder network as described above is shown, but Figure 6A The electrode structure 604 can be incorporated into other resonator configurations, such as the DMS design.

[0078] Figure 11 It can be used in it Figure 10 A functional block diagram of at least a portion of a simplified example of a wireless transceiver circuit 1100, comprising a filter circuit 1000, the filter circuit 1000 including... Figure 6A The electrode structure is 604. Transceiver circuitry 1100 is configured to receive a signal / information (shown as I and Q values) for transmission provided to one or more baseband filters 1112. The filtered output is provided to one or more mixers 1114. The output from one or more mixers 1114 is provided to a driver amplifier 1116, and the output of the driver amplifier 1116 is provided to a power amplifier 1118 to generate an amplified signal for transmission. The amplified signal is output to antenna 1122 through one or more filters 1120 (e.g., duplexers, if used as frequency division duplex transceivers or other filters). The one or more filters 1120 may include... Figure 10 The filter circuit 1000, and may include Figure 6AThe electrode structure 604. Antenna 1122 can be used to wirelessly transmit and receive data. Transceiver circuitry 1100 includes a receive path that is provided to a low-noise amplifier (LNA) 1124 and another filter 1126 via one or more filters 1120, and then down-converted from the receive frequency to the baseband frequency via one or more mixer circuits 1128 before the signal is further processed (e.g., provided to an analog-to-digital converter, then demodulated in the digital domain, or otherwise processed). A separate filter may be present for the receive circuitry (e.g., it may have a separate antenna or a separate receive filter), which can be used... Figure 10 The filter circuit 1000 is used to implement this. Furthermore, the transceiver circuit 1100 shown represents a simplified example of a transceiver architecture, and other architectures with different filter configurations (e.g., shared or non-shared antennas) are possible.

[0079] Figure 12 This is a diagram of an environment 1200 including electronic device 1202, which includes, for example, electronic device 1202. Figure 11 The transceiver circuit 1100 of the wireless transceiver 1296 (and may include the use of Figure 6A (The filter of electrode structure 604). In environment 1200, electronic device 1202 communicates with base station 1204 via wireless link 1206. As shown, electronic device 1202 is depicted as a smartphone. However, electronic device 1202 can be implemented as any suitable computing 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, desktop computer, tablet, server computer, network attached storage (NAS) device, smart home appliance, vehicle-based communication system, Internet of Things (IoT) device, sensor or security device, asset tracker, etc.

[0080] Base station 1204 communicates with electronic device 1202 via wireless link 1206, which can be implemented as any suitable type of wireless link. Although depicted as a base station tower in a cellular radio network, base station 1204 can represent or be implemented as another device, such as a satellite, terrestrial broadcast tower, access point, peer-to-peer device, mesh network node, fiber optic line, or another electronic device generally as described above. Therefore, electronic device 1202 can communicate with base station 1204 or another device via a wired connection, a wireless connection, or a combination thereof. Wireless link 1206 can include a downlink for transmitting data or control information from base station 1204 to electronic device 1202, and an uplink for transmitting other data or control information from electronic device 1202 to base station 1204. Wireless link 1206 can be implemented using any suitable communication protocol or standard, such as 3GPP LTE, 3GPP NR 5G, IEEE 802.11, IEEE 802.16, Bluetooth. TM wait.

[0081] Electronic device 1202 includes processor 1280 and memory 1282. Memory 1282 may be or form part of a computer-readable storage medium. Processor 1280 may include any type of processor (such as an application processor or a multi-core processor) configured to execute processor-executable instructions (e.g., code) stored in memory 1282. Memory 1282 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 1282 is implemented to store instructions 1284, data 1286, and other information of electronic device 1202, and therefore, when configured as a computer-readable storage medium or part thereof, memory 1282 does not include transient propagation signals or carrier waves.

[0082] Electronic device 1202 may also include input / output port 1290 (I / O port 116). I / O port 1290 enables data exchange or interaction with other devices, networks, users, or components of the device.

[0083] Electronic device 1202 may also include signal processor (SP) 1292 (e.g., such as digital signal processor (DSP)). Signal processor 1292 may function similarly to a processor and is capable of executing instructions and / or processing information in conjunction with memory 1282.

[0084] For communication purposes, electronic device 1202 also includes a modem 1294, a wireless transceiver 1296, and an antenna (not shown). The wireless transceiver 1296 uses radio frequency (RF) wireless signals to provide connectivity to a corresponding network and other electronic devices connected thereto, and may include... Figure 11 The transceiver circuit 1100. The wireless transceiver 1296 can facilitate communication over any suitable type of wireless network, such as wireless local area network (LAN) (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).

[0085] Examples of implementation methods are described in the following numbered clauses:

[0086] 1. An electroacoustic device, comprising:

[0087] piezoelectric materials; and

[0088] Electrode structure, including:

[0089] First busbar and second busbar;

[0090] The electrode fingers are arranged in an interdigitated manner and include a first plurality of fingers connected to a first busbar and a second plurality of fingers connected to a second busbar;

[0091] A first conductive structure is disposed between each of the first plurality of fingers and between the first busbar and the second plurality of fingers, the first conductive structure having a height less than the height of the first plurality of fingers; and

[0092] A second conductive structure is disposed between each of the second plurality of fingers and between the second busbar and the first plurality of fingers, the second conductive structure having a height less than the height of the second plurality of fingers.

[0093] 2. The electroacoustic device according to Clause 1, wherein the height of the first conductive structure is less than half the height of the first plurality of fingers, and wherein the height of the second conductive structure is less than half the height of the second plurality of fingers.

[0094] 3. An electroacoustic device according to any one of clauses 1 to 2, wherein the height of the first conductive structure is between 5 nanometers and 20 nanometers, and the height of the second conductive structure is between 5 nanometers and 20 nanometers.

[0095] 4. An electroacoustic device according to any one of clauses 1 to 3, wherein a first conductive structure is connected to a first busbar, and a second conductive structure is connected to a second busbar.

[0096] 5. An electroacoustic device according to any one of clauses 1 to 4, wherein the electrode fingers have a central region, the central region having a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

[0097] 6. An electroacoustic device according to Clause 5, wherein structural characteristics correspond to a portion of each electrode finger in the electrode fingers, and in the first trap region and the second trap region, the portion has an increased width or an increased height relative to the central region.

[0098] 7. An electroacoustic device according to Clause 5, wherein the structural characteristics correspond to at least one of the following: dielectric material located above the trap region, mass load within the trap region, or structural effects of fine-tuning operation.

[0099] 8. An electroacoustic device according to any one of clauses 5 to 7, wherein the sound velocity in the region of the electroacoustic device defined by the first conductive structure and the second conductive structure is higher than that in the region of the electroacoustic device defined by the first trap region, the second trap region and the central region.

[0100] 9. An electroacoustic device according to Clause 8, wherein the speed of sound in the first trap region and the second trap region is lower than the speed of sound in the central region.

[0101] 10. An electroacoustic device according to Clause 5, wherein the size of the trap region in the direction in which the electrode fingers extend is between half the pitch of the electrode fingers and twice the pitch of the electrode fingers.

[0102] 11. An electroacoustic device according to Clause 1, wherein the electrode fingers have a central region having a first trap region and a second trap region respectively positioned on the boundary of the central region, wherein the sound velocity in the region of the electroacoustic device defined by the first trap region and the second trap region is lower than that in the region of the electroacoustic device defined by the central region.

[0103] 12. An electroacoustic device according to any one of clauses 1 to 11, wherein the dimension of the first conductive structure in the direction in which the electrode fingers extend is between 1.25 times and 4 times the wavelength of the operating frequency of the electroacoustic device.

[0104] 13. An electroacoustic device according to any one of clauses 1 to 12, wherein the electrode fingers extend in a direction orthogonal to the directions of the first and second busbars.

[0105] 14. An electroacoustic device according to any one of clauses 1 to 13, wherein electrode fingers extend in a direction orthogonal to the direction of the first conductive structure and the second conductive structure.

[0106] 15. An electroacoustic device according to any one of clauses 1 to 14, wherein the piezoelectric material includes lithium tantalate (LiTaO3).

[0107] 16. An electroacoustic device according to any one of clauses 1 to 15 further includes:

[0108] substrate;

[0109] A trap-rich layer is formed as part of the substrate or disposed on the substrate; and

[0110] A dielectric material layer is disposed on the substrate, and a piezoelectric material is disposed on the dielectric material layer.

[0111] 17. An electroacoustic device according to any one of clauses 1 to 15 further includes:

[0112] Substrate; and

[0113] A compensation layer is disposed on the substrate, and a piezoelectric material is disposed between the electrode structure and the compensation layer.

[0114] 18. An electroacoustic device according to any one of clauses 1 to 17, wherein the electroacoustic device is at least a portion of a SAW resonator that forms part of a filter circuit.

[0115] 19. An electroacoustic device pursuant to Clause 18, wherein the filter circuitry is part of the transceiver.

[0116] 20. A method for forming an electroacoustic device, comprising:

[0117] Forming a piezoelectric material layer; and

[0118] An electrode structure is formed on or above a piezoelectric material, wherein the formation of the electrode structure includes:

[0119] Forming the first busbar and the second busbar;

[0120] Forming electrode fingers arranged in an interdigitated manner, wherein forming electrode fingers includes forming a first plurality of fingers connected to a first busbar and forming a second plurality of fingers connected to a second busbar;

[0121] A first conductive structure is formed, the first conductive structure being disposed between each of the first plurality of fingers, the first conductive structure having a height smaller than the height of the first plurality of fingers; and

[0122] A second conductive structure is formed, which is disposed between each of the second plurality of fingers, and the second conductive structure is formed to have a height smaller than the height of the second plurality of fingers.

[0123] 21. The method according to Clause 20, wherein the electrode fingers have a central region and a first trap region and a second trap region located on the boundary of the central region, wherein the method further includes adjusting or forming structural characteristics of the electroacoustic device in the first trap region and the second trap region to reduce the speed of sound.

[0124] 22. An electroacoustic device, comprising:

[0125] piezoelectric materials; and

[0126] Electrode structure, including:

[0127] First busbar and second busbar;

[0128] Electrode fingers, arranged in an interdigitated manner, are connected to either the first busbar or the second busbar; and

[0129] A device for controlling the speed of sound in a first region and a second region, the first region being between a first busbar and an electrode finger, and the second region being between a second busbar and an electrode finger, the device for controlling the speed of sound having a height less than the height of the electrode finger.

[0130] 23. An electroacoustic device according to Clause 22, wherein the means for controlling the speed of sound has a height less than half the height of the electrode fingers.

[0131] 24. An electroacoustic device according to any one of clauses 22 to 23, wherein the electrode fingers have a central region having a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

[0132] 25. An electrode structure for an electroacoustic device, comprising:

[0133] First busbar and second busbar;

[0134] The electrode fingers are arranged in an interdigitated manner and include a first plurality of fingers connected to a first busbar and a second plurality of fingers connected to a second busbar;

[0135] A first conductive structure is disposed between the ends of a first busbar and a plurality of fingers, the first conductive structure having a height less than the height of the first plurality of fingers; and

[0136] A second conductive structure is disposed between the ends of the second busbar and the first plurality of fingers, and the second conductive structure has a height less than the height of the second plurality of fingers.

[0137] 26. The electrode structure according to Clause 25, wherein the height of the first conductive structure is less than half the height of the first plurality of fingers, and wherein the height of the second conductive structure is less than half the height of the second plurality of fingers.

[0138] 27. An electrode structure according to any one of clauses 25 to 26, wherein a first conductive structure is connected to a first busbar, and a second conductive structure is connected to a second busbar.

[0139] 28. An electrode structure according to any one of clauses 25 to 27, wherein the electrode fingers have a central region having a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

[0140] 29. An electrode structure according to any one of clauses 25 to 28, wherein the electrode structure is disposed on a piezoelectric material comprising lithium tantalate (LiTaO3).

[0141] 30. A wireless communication device comprising an electroacoustic device according to Clause 1.

[0142] 31. A method for filtering electrical signals via an electroacoustic device, the electroacoustic device comprising a piezoelectric material and an interdigital transducer, the method comprising:

[0143] Provide electrical signals to the terminals of the interdigital transducer; and

[0144] Transverse acoustic modes are reduced by conductive structures that are respectively connected between the corresponding busbars and electrode fingers of the interdigitated transducer. The height of the conductive structures is smaller than the height of the electrode fingers.

[0145] 32. An electroacoustic device, comprising:

[0146] piezoelectric materials; and

[0147] Electrode structure, including:

[0148] Electrode fingers, the electrode fingers are arranged in an interdigitated manner, and include a first plurality of fingers and a second plurality of fingers;

[0149] A first conductive structure is connected to each of the first plurality of fingers and to the relationships between each of the first plurality of fingers, the first conductive structure having a height less than the height of the first plurality of fingers; and

[0150] A second conductive structure is connected to each of the second plurality of fingers and to the distance between each of the second plurality of fingers, the second conductive structure having a height less than the height of the second plurality of fingers.

[0151] The various operations of the above methods can be performed by any suitable device capable of performing the corresponding functions. This device may include various hardware components and / or software components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors.

[0152] As an example, the elements described herein, or any portion thereof, or any combination thereof, may be implemented as a “processing system” including one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system-on-a-chip (SoCs), baseband processors, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuitry, and other suitable hardware configured to perform the various functionalities described throughout this disclosure. One or more processors in a processing system may execute software. Software should be interpreted broadly as representing instructions, instruction sets, code, code segments, program code, programs, subroutines, software components, application programs, software applications, software packages, routines, subroutines, objects, executable documents, threads of execution, procedures, functions, etc., whether or not referred to as software, firmware, middleware, microcode, hardware description languages, or others.

[0153] Therefore, in one or more example embodiments, the described functions or circuit blocks can be implemented in hardware, software, or any combination thereof. If implemented in software, these functions can be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any available medium accessible by a computer. By way of example and not limitation, such computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of computer-readable media of the foregoing types, or any other medium that can be used to store computer-executable code in the form of computer-accessible instructions or data structures. In some aspects, components described in circuitry can be implemented in hardware, software, or any combination thereof.

[0154] Generally, in the case of the operations shown in the figure, these operations may have corresponding devices and functional components with similar numbers.

[0155] As used herein, the term "determine" encompasses a variety of actions. For example, "determine" can include calculation, operation, processing, derivation, investigation, searching (e.g., searching in a table, database, or other data structure), confirmation, etc. Furthermore, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), etc. Additionally, "determine" can include resolving, selecting, picking, establishing, etc.

[0156] As used herein, the phrase “at least one of” in a list of items refers to any combination of these items, including a single member. As an example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbb, bbc, cc, and ccc, or any other order of a, b, and c).

[0157] The methods disclosed herein include one or more steps or actions for implementing the methods. The method steps and / or actions may be interchanged without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions may be modified without departing from the scope of the claims. It should be understood that the claims are not limited to the precise configuration and components described above. Various modifications, alterations, and variations may be made to the arrangement, operation, and details of the described methods and apparatus without departing from the scope of the claims.

Claims

1. An electroacoustic device, comprising: piezoelectric materials; as well as Electrode structure, including: First busbar and second busbar; The electrode fingers are arranged in an interdigitated manner and include a first plurality of fingers connected to the first busbar and a second plurality of fingers connected to the second busbar; A first conductive structure is disposed between each of the first plurality of fingers and between the first busbar and the second plurality of fingers, the first conductive structure having a height less than the height of the first plurality of fingers; and A second conductive structure is disposed between each of the second plurality of fingers and between the second busbar and the first plurality of fingers, the second conductive structure having a height less than the height of the second plurality of fingers.

2. The electroacoustic device according to claim 1, wherein the height of the first conductive structure is less than half the height of the first plurality of fingers, and the height of the second conductive structure is less than half the height of the second plurality of fingers.

3. The electroacoustic device according to claim 1, wherein the height of the first conductive structure is between 5 nanometers and 20 nanometers, and wherein the height of the second conductive structure is between 5 nanometers and 20 nanometers.

4. The electroacoustic device according to claim 1, wherein the first conductive structure is connected to the first busbar, and wherein the second conductive structure is connected to the second busbar.

5. The electroacoustic device according to claim 1, wherein the electrode fingers have a central region, the central region having a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

6. The electroacoustic device of claim 5, wherein the structural characteristics correspond to a portion of each of the electrode fingers, and the portion has an increased width or increased height relative to the central region within the first trap region and the second trap region.

7. The electroacoustic device of claim 5, wherein the structural characteristic corresponds to at least one of the following: a dielectric material located above the trap region, a mass load within the trap region, or a structural effect of fine-tuning operation.

8. The electroacoustic device of claim 5, wherein the sound velocity in the region of the electroacoustic device defined by the first conductive structure and the second conductive structure is higher than that in the region of the electroacoustic device defined by the first trap region, the second trap region and the central region.

9. The electroacoustic device according to claim 8, wherein the speed of sound in the first trap region and the second trap region is lower than the speed of sound in the central region.

10. The electroacoustic device of claim 5, wherein the size of the trap region in the direction in which the electrode fingers extend is between half the pitch of the electrode fingers and twice the pitch of the electrode fingers.

11. The electroacoustic device of claim 1, wherein the electrode fingers have a central region, the central region having a first trap region and a second trap region respectively positioned on the boundary of the central region, wherein the sound velocity in the region of the electroacoustic device defined by the first trap region and the second trap region is lower than in the region of the electroacoustic device defined by the central region.

12. The electroacoustic device of claim 1, wherein the dimension of the first conductive structure in the direction in which the electrode fingers extend is between 1.25 times and 4 times the wavelength of the operating frequency of the electroacoustic device.

13. The electroacoustic device of claim 1, wherein the electrode fingers extend in a direction orthogonal to the directions of the first busbar and the second busbar.

14. The electroacoustic device according to claim 1, wherein the electrode fingers extend in a direction orthogonal to the directions of the first conductive structure and the second conductive structure.

15. The electroacoustic device according to claim 1, wherein the piezoelectric material comprises lithium tantalate (LiTaO3).

16. The electroacoustic device according to claim 1, further comprising: substrate; A trap-rich layer is formed as part of the substrate or disposed on the substrate; as well as A dielectric material layer is disposed on the substrate, and the piezoelectric material is disposed on the dielectric material layer.

17. The electroacoustic device according to claim 1, further comprising: substrate; as well as A compensation layer is disposed on the substrate, and the piezoelectric material is disposed between the electrode structure and the compensation layer.

18. The electroacoustic device of claim 1, wherein the electroacoustic device is at least a portion of a SAW resonator, the SAW resonator forming part of a filter circuit.

19. The electroacoustic device of claim 18, wherein the filter circuit is part of a transceiver.

20. A method for forming an electroacoustic device, comprising: Forming a piezoelectric material layer; as well as An electrode structure is formed on or above the piezoelectric material, wherein forming the electrode structure includes: Forming the first busbar and the second busbar; Forming electrode fingers arranged in an interdigitated manner, wherein forming the electrode fingers includes forming a first plurality of fingers connected to the first busbar and forming a second plurality of fingers connected to the second busbar; A first conductive structure is formed, the first conductive structure being disposed between each of the first plurality of fingers, the first conductive structure having a height smaller than the height of the first plurality of fingers; and A second conductive structure is formed, which is disposed between each of the second plurality of fingers, and the second conductive structure has a height smaller than the height of the second plurality of fingers.

21. The method of claim 20, wherein the electrode fingers have a central region and a first trap region and a second trap region located on the boundary of the central region, wherein the method further comprises adjusting or forming structural characteristics of the electroacoustic device in the first trap region and the second trap region to reduce the speed of sound.

22. An electroacoustic device, comprising: piezoelectric materials; as well as Electrode structure, including: First busbar and second busbar; Electrode fingers, arranged in an interdigitated manner, are connected to the first busbar or the second busbar; and A device for controlling the speed of sound in a first region and a second region, the first region being between a first busbar and the electrode fingers, the second region being between a second busbar and the electrode fingers, the device for controlling the speed of sound having a height less than the height of the electrode fingers.

23. The electroacoustic device of claim 22, wherein the means for controlling the speed of sound has a height less than half the height of the electrode fingers.

24. The electroacoustic device of claim 22, wherein the electrode fingers have a central region, the central region having a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

25. An electrode structure for an electroacoustic device, comprising: First busbar and second busbar; The electrode fingers are arranged in an interdigitated manner and include a first plurality of fingers connected to the first busbar and a second plurality of fingers connected to the second busbar; A first conductive structure is disposed between the ends of the first busbar and the second plurality of fingers, the first conductive structure having a height less than the height of the first plurality of fingers; as well as A second conductive structure is disposed between the ends of the second busbar and the first plurality of fingers, and the second conductive structure has a height less than the height of the second plurality of fingers.

26. The electrode structure according to claim 25, wherein the height of the first conductive structure is less than half the height of the first plurality of fingers, and wherein the height of the second conductive structure is less than half the height of the second plurality of fingers.

27. The electrode structure according to claim 25, wherein the first conductive structure is connected to the first busbar, and wherein the second conductive structure is connected to the second busbar.

28. The electrode structure of claim 25, wherein the electrode fingers have a central region, the central region having a first trap region and a second trap region respectively located on the boundary of the central region, wherein the structural characteristics of the electroacoustic device are different relative to the central region in the first trap region and the second trap region.

29. The electrode structure according to claim 25, wherein the electrode structure is disposed on a piezoelectric material comprising lithium tantalate (LiTaO3).

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