Elastic wave device and electronic product

Abstract

The embodiment of the invention provides an elastic wave device and an electronic product. The elastic wave device comprises a piezoelectric layer; the IDT electrode layer is arranged on the piezoelectric layer, the IDT electrode layer comprises a first bus bar and a second bus bar which are oppositely arranged along a first direction, and a part between the first bus bar and the second bus bar is defined as an interdigital region; the electrode fingers are arranged in the interdigital area, the electrode fingers comprise a plurality of first electrode fingers and a plurality of second electrode fingers which are arranged at intervals in the second direction, first intervals are formed between the first electrode fingers and the second bus bars, and first intervals are formed between the second electrode fingers and the first bus bars; the interdigital area comprises a central area and additional film areas, the two edges of the central area in the first direction do not exceed the edges of the sides, away from the bus bar, of the first electrode fingers and the second electrode fingers, and the additional film areas are arranged on the two sides of the central area; and the additional film is arranged on the piezoelectric substrate, the additional film is arranged in the additional film area, and the material of the additional film is silicon dioxide, silicon oxide, silicon nitride, HfO2, silicon, resin, PI or titanium oxide.

Description

Elastic wave devices and electronic products Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to an elastic wave device and an electronic product. Background Technology

[0002] Surface acoustic wave (SAW) resonators, with their advantages of miniaturization and high reliability, have become core components in the RF filtering stage of wireless communication systems and are widely used in various terminal devices. Their working principle is based on interdigital transducers (IDTs) converting electrical signals into surface acoustic waves that propagate along the surface of the medium. However, in actual propagation, the sound wave does not strictly propagate in the direction perpendicular to the extension of the interdigital fingers (not the Y-direction), but rather has a propagation component in the Y-direction (the direction of the interdigital fingers' extension). When this component satisfies the resonance condition, it excites transverse modes. These transverse modes create additional resonance peaks within the resonator's passband and adjacent frequency bands, directly leading to increased passband ripple and deterioration of insertion loss, severely affecting the stability and consistency of filtering performance.

[0003] Therefore, there is an urgent need for an elastic wave device to suppress transverse modes and improve the stability and consistency of filtering performance. Summary of the Invention

[0004] Therefore, in order to overcome at least some of the defects and deficiencies in the prior art, embodiments of the present invention provide an elastic wave device and an electronic product.

[0005] Specifically, in one aspect, the elastic wave device provided in this embodiment of the invention includes: a piezoelectric layer; an IDT electrode layer disposed on the piezoelectric layer, the IDT electrode layer including: two busbars disposed opposite each other along a first direction, including a first busbar and a second busbar, the portion between the first busbar and the second busbar defined as an interdigitated region; electrode fingers disposed in the interdigitated region, the electrode fingers including a plurality of first electrode fingers and a plurality of second electrode fingers spaced apart along a second direction, the first electrode fingers extending from the first busbar to the second busbar, the second electrode fingers extending from the second busbar to the first busbar, the first electrode fingers extending from the first busbar to the second busbar, the second electrode fingers extending from the second busbar to the first busbar, the first electrode fingers extending from the first busbar to the second busbar, the second electrode fingers extending from the second busbar to the first busbar, the first electrode fingers extending from the first busbar to the second busbar, the second electrode fingers extending from the second busbar to the first busbar, the second electrode fingers extending from the first busbar to the second ... One electrode finger has a first gap with the second busbar, and the second electrode finger has a first gap with the first busbar; the interdigitated region includes a central region and an additional film region, the two edges of the central region along the first direction do not exceed the edges of the first electrode finger and the second electrode finger away from the busbar, the additional film region is disposed on both sides of the central region and is closer to the busbar than the central region; the additional film is disposed on the piezoelectric substrate and is disposed in the additional film region, the material of the additional film is silicon dioxide, silicon oxide, silicon nitride, HfO2, silicon, resin, PI or titanium oxide.

[0006] In one specific embodiment of the invention, the additional film has a first edge away from the central region along the first direction, the first edge being flush with the edge of the electrode finger near the first interval.

[0007] In one specific embodiment of the invention, the additional membrane has a first edge extending away from the central region along the first direction, the first edge extending to the first interval.

[0008] In one specific embodiment of the present invention, the additional membrane area is located between the central area and the busbar, and the end of the additional membrane away from the central area is disposed adjacent to the busbar.

[0009] In one specific embodiment of the present invention, one end of the additional film region near the central region is flush with the edge of the first electrode finger and the edge of the second electrode finger, respectively.

[0010] In one specific embodiment of the present invention, the additional membrane region partially overlaps with the busbar, and the additional membrane region completely covers the first interval.

[0011] In one specific embodiment of the present invention, the edge of the additional film region near the central region is flush with the edges of the first electrode finger and the second electrode finger, respectively.

[0012] In another aspect, embodiments of the present invention also provide an elastic wave device, comprising: a piezoelectric layer; an IDT electrode layer disposed on the piezoelectric layer, the IDT electrode layer comprising: two busbars disposed opposite each other along a first direction, including a first busbar and a second busbar, the portion between the first busbar and the second busbar defined as an interdigitated region; electrode fingers disposed in the interdigitated region, the electrode fingers comprising a plurality of first electrode fingers and a plurality of second electrode fingers disposed at intervals along a second direction, the first electrode fingers extending from the first busbar to the second busbar, and the second electrode fingers extending from the second busbar to the first busbar; and dummy electrode fingers comprising a plurality of first dummy electrode fingers and a plurality of second dummy electrode fingers, the first dummy electrode fingers extending from the first busbar to the second busbar. The two electrode fingers extend to the side, the second dummy electrode finger extends from the second busbar to the side of the first electrode finger, and there is a second gap between the first dummy electrode finger and the second electrode finger; the interdigitated region includes a central region and an additional film region, the two edges of the central region along the first direction do not exceed the edges of the first electrode finger and the second electrode finger away from the busbar, the additional film region is disposed on both sides of the central region, and is closer to the busbar than the central region; the additional film is disposed on the piezoelectric substrate, and the additional film is disposed in the additional film region, the material of the additional film is silicon dioxide, silicon oxide, silicon nitride, HfO2, silicon, resin, PI or titanium oxide.

[0013] In one specific embodiment of the invention, the additional film has a first edge away from the central region along the first direction, the first edge being flush with the edge of the electrode finger near the second interval.

[0014] In one embodiment of the invention, the additional film has a first edge extending away from the central region along the first direction, the first edge extending into the second interval. In another embodiment of the invention, the IDT electrode layer further includes two dual buses located on the side of the busbar away from the interdigitated region and two connecting electrodes located between the dual buses and the busbar.

[0015] In one specific embodiment of the present invention, the additional film is disposed between the piezoelectric substrate and the IDT electrode layer, or the additional film is disposed on the surface of the IDT electrode layer away from the piezoelectric substrate.

[0016] In one specific embodiment of the present invention, the thickness of the additional membrane is less than 0.1λ, where λ is the wavelength of the surface acoustic wave.

[0017] In another aspect, embodiments of the present invention also provide an electronic product comprising the elastic wave device described above.

[0018] As can be seen from the above, the elastic wave device provided in this embodiment of the invention forms a high and low sound velocity region with the interdigitated region by setting an additional membrane in the additional membrane region. This difference in sound velocity blocks the propagation and resonant excitation of the Y-direction sound wave component, suppressing lateral energy leakage and improving the stability and consistency of the filtering performance. On the other hand, introducing an additional membrane into the interval region can affect the dielectric constant in that region, adjust the path and intensity of the distorted electric field in the interval region, and also affect the elastic constant in that region, reducing the nonlinear effects caused by deformation. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 is a top view of an elastic wave device provided in an embodiment of the present invention; Figure 2 is a cross-sectional view of the elastic wave device in Figure 1 along AA; Figure 3 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 4 is a cross-sectional view of the elastic wave device in Figure 3 along AA; Figure 5 is a top view of yet another elastic wave device provided in an embodiment of the present invention; Figure 6 is a cross-sectional view of the elastic wave device in Figure 5 along AA; Figure 7A is a top view of yet another elastic wave device provided in an embodiment of the present invention; Figure 7B is a cross-sectional view of the elastic wave device in Figure 7A along AA. Figure 8A is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 8B is a cross-sectional view of the elastic wave device in Figure 8A along AA; Figure 9 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 10 is a cross-sectional view of the elastic wave device in Figure 9 along AA; Figure 11 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 12 is a cross-sectional view of the elastic wave device in Figure 11 along AA; Figure 13 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 14 is a cross-sectional view of the elastic wave device in Figure 13 along AA. Figure 15 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 16 is a cross-sectional view of the elastic wave device in Figure 15 along AA; Figure 17 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 18 is a cross-sectional view of the elastic wave device in Figure 17 along AA; Figure 19 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 20 is a cross-sectional view of the elastic wave device in Figure 19 along AA; Figure 21 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 22 Figure 21 is a cross-sectional view of the elastic wave device along AA; Figure 23 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 24 is a cross-sectional view of the elastic wave device in Figure 23 along AA; Figure 25 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 26 is a cross-sectional view of the elastic wave device in Figure 25 along AA; Figure 27 is a top view of another elastic wave device provided in an embodiment of the present invention; Figure 28 is a cross-sectional view of the elastic wave device in Figure 27 along AA; Figure 29 is a sound velocity variation diagram of the elastic wave device in the embodiment of Figure 3.

[0021] Key component labels: 10, Connection area; 20, Interdigitated area; 21, Central area; 22, Additional film area; 100, IDT electrode layer; 110, Busbar; 111, First busbar; 112, Second busbar; 113, First dual bus; 114, Second dual bus; 115, Connection electrode; 120, Electrode finger; 121, First electrode finger; 122, Second electrode finger; 130, Dummy electrode finger; 131, First dummy electrode finger; 132, Second dummy electrode finger; 133, First spacer; 134, Second spacer; 200, Substrate; 210, Support layer; 220, Dielectric layer; 230, Piezoelectric layer; 300, Additional film; 301, First edge. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] It should be noted that all directional indicators (such as up, down, left, right, front, back, top, and bottom) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the attached figures). If the specific posture changes, the directional indicator will also change accordingly. Furthermore, the term "vertical" used in the embodiments and claims refers to an angle of 90° between two components or a deviation of -5° to +5°, and the term "parallel" refers to an angle of 0° between two components or a deviation of -5° to +5°.

[0024] In the embodiments of this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0025] Referring to Figures 1 and 2, this embodiment of the invention provides a surface acoustic wave resonator (SAW) including a piezoelectric layer 230, an IDT electrode layer 100, and an additional film 300. The IDT electrode layer 100 is disposed on the piezoelectric layer 230 and includes busbars 110 and electrode fingers 120. Two busbars 110 are arranged opposite each other along a first direction, and the two busbars 110 include a first busbar 111 and a second busbar 112 arranged opposite each other along the first direction. As shown in Figure 1, the portion between the first busbar 111 and the second busbar 112 is defined as the interdigitated region 20, and the area between the first busbar 111 and the second busbar 112 is defined as the connection region 10. The two connection regions 10 are arranged opposite each other along the first direction, and the interdigitated region 20 is located between the two connection regions 10. The interdigitated region 20 includes a central region 21 and additional film regions 22 located on both sides of the central region 21. Furthermore, the two edges of the central region 21 along the first direction (i.e., the junction with the additional membrane region 22) do not exceed the edges of the first electrode fingers 121 and the second electrode fingers 122 on the side away from the busbar 110. Compared to the central region 21, the additional membrane region 22 is closer to the busbar 110. The electrode fingers 120 are disposed in the interdigitated region 20. The electrode fingers 120 include a plurality of first electrode fingers 121 and a plurality of second electrode fingers 122 spaced apart along the second direction. The first electrode fingers 121 extend from the first busbar 111 to the second busbar 112, and the second electrode fingers 122 extend from the second busbar 112 to the first busbar 111. There is a first gap 133 between the first electrode fingers 121 and the second busbar 112, and there is a first gap 133 between the second electrode fingers 122 and the first busbar 111. An additional film 300 is disposed on the piezoelectric substrate 200 and in the additional film region 22. The material of the additional film 300 can be a non-metallic material, such as silicon oxide, silicon nitride, HfO2, silicon, resin, PI, titanium oxide, etc. In this embodiment, silicon dioxide is used as the material of the additional film.

[0026] In this embodiment of the elastic wave device, a silicon dioxide supplementary film 300 is disposed in the supplementary film region 22. Due to the low sound velocity mass load of silicon dioxide, a high-low sound velocity region is formed in the interdigitated region 20. The sound velocity difference blocks the propagation and resonance excitation of the Y-direction (i.e., the first direction) sound wave component, suppressing lateral energy leakage and improving the stability and consistency of filtering performance. The supplementary film 300 is disposed on both sides of the central region 20 along the first direction. The sound velocity at the location of the supplementary film 300 is lower than that in the central region 20, and it also increases the sound velocity difference between it and the first interval (or the second interval mentioned below). Since the core cause of the lateral mode is that the sound wave component propagating in the Y direction satisfies the resonance condition and causes energy leakage, the sound velocity difference in the high-low sound velocity region forms an energy propagation barrier, directly blocking the propagation and resonance excitation of the Y-direction sound wave component, thereby suppressing lateral energy leakage. After the lateral mode is suppressed, the ineffective loss of the main mode energy is reduced, the main mode Q value of the elastic wave device can be improved, and ultimately the filtering performance is improved.

[0027] Referring to Figures 3 and 4, this embodiment of the invention also provides a surface acoustic wave resonator (SAW). Compared with the embodiment in Figure 1, the difference lies in that the IDT electrode layer 100 further includes dummy electrode fingers 130. The dummy electrode fingers 130 include a plurality of first dummy electrode fingers 131 and a plurality of second dummy electrode fingers 132. The first dummy electrode fingers 131 extend from the first busbar 111 towards the second electrode fingers 122, and the second dummy electrode fingers 132 extend from the second busbar 112 towards the first electrode fingers 121. A second gap 134 exists between the first dummy electrode fingers 131 and the second electrode fingers 122, and a second gap 134 exists between the second dummy electrode fingers 132 and the first electrode fingers 121. An additional film 300 is disposed on the piezoelectric layer 230 and in the additional film region 22. The material of the additional film 300 can be a non-metallic material, such as silicon oxide, silicon nitride, HfO2, silicon, resin, PI, titanium oxide, etc. In this embodiment, silicon dioxide is used as the material of the additional film. By setting up the dummy electrode 130, the dummy electrode 130 can simulate the sound field boundary conditions of the main interdigital finger. By filling the "sound field gap" between the central area and the busbar, the dummy electrode 130 can adjust the sound velocity distribution in the Y direction, further enhance the sound velocity difference barrier effect in the high and low sound velocity regions, block the propagation and resonance excitation of the Y direction sound wave component, reduce lateral energy leakage, improve the Q value, and thus improve the filtering performance of the elastic wave device.

[0028] Specifically, as shown in Figure 2, the piezoelectric substrate 200 may include a support layer 210, a dielectric layer 220, and a piezoelectric layer 230. The dielectric layer 220 is disposed on the support layer 210, the piezoelectric layer 230 is disposed on the dielectric layer 220, and the IDT electrode layer 100 is disposed on the piezoelectric layer 230. The support layer 210 may be made of materials such as sapphire, silicon, silicon carbide, spinel, gallium nitride, heavy metals, silicon nitride, aluminum nitride, diamond, quartz, or glass. It is mainly used to enhance the overall mechanical strength of the device, adjust the flatness of the substrate, and reduce the interference of the substrate material on the acoustic and electrical properties of the upper layer. The dielectric layer 220 may be made of materials such as silicon dioxide or silicon nitride. The dielectric layer 220 can achieve electrical isolation and dielectric buffering, adjust the sound velocity matching between the upper and lower layers, and help optimize the sound field distribution to reduce insertion loss. The piezoelectric layer 230 can be made of materials such as lithium niobate, lithium tantalate, or quartz. As the core functional layer of the SAW device, it completes the mutual conversion between electrical signals and surface acoustic waves through the piezoelectric effect. The IDT electrode layer 100 can be made of aluminum, aluminum-copper alloy, or gold. It consists of busbars and interdigitated electrode fingers. When an electrical signal is input, it can excite the piezoelectric layer to generate surface acoustic waves. When the surface acoustic waves are received, they are converted into electrical signals, realizing the core acoustic-electric coupling.

[0029] In one embodiment of this invention, the thickness of the dielectric layer 220 can be 3-4 μm, the material of the IDT electrode layer 100 can be composed of Cu and Al, the piezoelectric layer 230 is selected as 42 tangential lithium niobate (42LT), and the support layer 210 is made of spinel; the length of the dummy electrode finger 130 can be 1 / 4λ (λ is the wavelength of the elastic wave), the second spacing 134 can be 0.4 μm, and the electrode duty cycle is 0.5. Of course, this embodiment is not limited to these limitations.

[0030] In this embodiment, the thickness of the additional film 300 is less than 0.1λ. This configuration allows for the utilization of the acoustic velocity difference and dielectric and elastic properties between the additional film 300 and the piezoelectric substrate 200 to synergistically suppress transverse modes and enhance second-order harmonic suppression within the existing device structure, without interfering with the normal propagation of surface acoustic waves and the acoustic-electric coupling efficiency. Furthermore, it improves the interlayer adhesion with the piezoelectric substrate 200 and the IDT electrode layer 100, reduces interface defects, and further enhances the consistency and long-term stability of the device performance.

[0031] In some embodiments of this example, the additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100. The additional film 300 is directly bonded to the piezoelectric substrate 200 and the IDT electrode layer 100, forming a high and low sound velocity interface that covers the entire domain. This distribution is more uniform and can completely block the propagation and resonant excitation of the Y-direction acoustic wave component, reducing the path of lateral energy leakage and being more conducive to second-order harmonic suppression. The energy loss of the main mode is further reduced, the Q value of the main mode is significantly improved, and the flatness of the filter passband is better. It can also optimize the bonding stability between the IDT electrode layer 100 and the piezoelectric substrate 200, reducing the impact of environmental factors on the acoustic-electric conversion; at the same time, the uniform sound velocity and dielectric distribution make the performance of each region of the device more consistent, improving the stability during mass production. In other embodiments of this example, the additional film 300 can also be disposed on the surface of the IDT electrode layer 100 away from the piezoelectric substrate 200, and on the upper surface of the piezoelectric substrate 200.

[0032] Referring to Figures 1 and 2, in the embodiment shown in Figure 1, the IDT electrode layer 100 includes busbars 110 and electrode fingers 120. An additional film 300 has a first edge 301 along a first direction away from the central region 21, and the first edge 301 is flush with the edge of the electrode fingers 120 near the first interval 133. Specifically, two additional films 300 are included, correspondingly positioned near the first busbar 110 and the second busbar 120. The first edge 301 of one additional film 300 is flush with the edge of the second electrode finger 122 near the first interval 133, and the first edge 301 of the other additional film 300 is flush with the edge of the first electrode finger 121 near the first interval 133. The additional films 300 are disposed between the piezoelectric substrate 200 and the IDT electrode layer 100. The flush arrangement of the additional films 300 with the edges of the electrode fingers 120 accurately defines the boundaries of the high and low sound velocity regions, avoiding blurring or abrupt changes in the sound velocity distribution boundaries. This precise boundary can specifically block the propagation path of the transverse acoustic wave component in the Y direction, suppress its resonant excitation, minimize transverse energy leakage, reduce ineffective energy loss of the master mode, and improve the master mode Q value. Furthermore, the precise alignment of the additional film 300 with the electrode finger 120 ensures the uniformity of sound velocity and dielectric constant distribution in various regions of the device, avoiding local performance fluctuations caused by boundary misalignment and improving performance consistency and stability. In this embodiment, the width of the additional film 300 is 0.5λ, and the thickness is set to 0.019λ. This size configuration can further optimize the acoustic-electric coupling efficiency of the electrode.

[0033] Referring to Figures 3 and 4, in the embodiment shown in Figure 3, the IDT electrode layer 100 includes a busbar 110, electrode fingers 120, and dummy electrode fingers 130. An additional film 300 has a first edge 301 located away from the central region 21 along a first direction, the first edge 301 being flush with the edge of the electrode fingers 120 near the second spacing 134. Specifically, two additional films 300 are included: one additional film 300 has its first edge 301 flush with the edge of the second electrode fingers 122 near the second spacing 134, and the other additional film 300 has its first edge 301 flush with the edge of the first electrode fingers 121 near the second spacing 134. The additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100. The precise alignment of the additional membrane 300 with the edge of the electrode finger 120 effectively blocks the propagation of transverse sound waves in the Y direction by clearly defining the high and low sound velocity boundaries. The dummy electrode finger 130 further fills the acoustic field gaps between the intervals and connection areas. Simulating the acoustic field characteristics of the electrode finger 120, the dummy electrode finger 130, in conjunction with the sound velocity difference barrier of the additional membrane 300, provides a double barrier against the resonant excitation and energy leakage of the Y-direction sound wave components, resulting in more thorough suppression of transverse modes. In this embodiment, the width of the additional membrane 300 is 0.6λ, and the thickness is set to 0.021λ. This dimensional configuration further optimizes the acoustic-electric coupling efficiency of the electrodes.

[0034] Referring to Figure 29, which shows the sound velocity variations in the corresponding embodiments of Figures 3 and 4, it can be seen that due to the mass load, the gap has the highest sound velocity because there are no electrode fingers (no metal mass loading). The busbar has the second highest sound velocity due to the weak scattering effect on elastic waves. Without the additional film, the sound velocity at the electrode fingers should be the same. However, due to the addition of the additional film, the electrode fingers are divided into a central region and an additional film region. The sound velocity in the additional film region is lower (because of the low sound velocity mass load of silicon oxide), dividing what was originally one sound velocity into two sound velocity segments. At the same time, the sound velocity difference between the additional film region and the gap is greater, further enhancing the sound velocity difference barrier effect in the high and low sound velocity regions, blocking the propagation and resonance excitation of the Y-direction sound wave component, reducing lateral energy leakage, increasing the Q value, and thus improving the filtering performance of the elastic wave device.

[0035] Referring to Figures 5 and 6, in the embodiment shown in Figure 5, the first edge 301 extends into the first gap 133. Introducing an additional film (e.g., silicon oxide material) into the gap region affects the dielectric constant of that region, adjusts the path and intensity of the distorted electric field in the gap region, and also affects the elastic constant of that region, mitigating the nonlinear effects caused by deformation. In this embodiment, the width of the additional film 300 is 0.6λ, and the thickness is set to 0.017λ. This dimensional configuration further optimizes the acoustic-electric coupling efficiency of the electrodes.

[0036] Referring to Figures 7A and 7B, in the embodiment shown in Figure 7A, compared to the embodiment in Figure 5, a dummy electrode finger 130 is also included. The additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100, with the first edge 301 extending into the second gap 134. The additional film 300 fills and covers the second gap 134, changing the elastic constant distribution in this region, weakening the nonlinear deformation caused by the "edge effect" when sound waves propagate to the gap, and in conjunction with electric field optimization, further suppressing the generation of second-order harmonics, resulting in better insertion loss performance. In this embodiment, the width of the additional film 300 is 0.6λ, and the thickness is set to 0.017λ. This size configuration can further optimize the acoustic-electric coupling efficiency of the electrode.

[0037] Figures 5, 6, 7A, and 7B illustrate two different embodiments of the elastic wave device of the present invention, in which the two additional films 300 extend toward the adjacent busbar in the embodiments shown in Figures 1 and 3. Figures 5 to 28 show several different elastic wave devices, differing from the embodiments shown in Figures 1 and 3 in that the two additional films 300 extend toward the adjacent busbar to different degrees, which can be used to meet the different requirements of elastic wave devices in different applications.

[0038] Referring to Figures 8A and 8B, in the embodiment shown in Figure 8A, the first edge 301 is flush with the edge of the dummy electrode finger 130 near the second interval 134, meaning the additional film 300 covers part of the electrode finger 120 and all of the second interval 134. In this embodiment, the width of the additional film 300 is 0.6λ and the thickness is set to 0.017λ. This size configuration can further optimize the acoustic-electric coupling efficiency of the electrodes.

[0039] Referring to Figures 9, 10, 11, and 12, in the embodiment shown in Figures 9 and 11, the additional film region 22 completely covers the portion between the central region 21 and the busbar 110, and the end of the additional film 300 away from the central region 21 is disposed adjacent to the busbar 110. The additional film 300 is located between the piezoelectric substrate 200 and the IDT electrode layer 100. In this embodiment, the width of the additional film 300 is 0.5λ, and the thickness is set to 0.019λ. This size configuration can further optimize the acoustic-electric coupling efficiency of the electrode.

[0040] Referring to Figures 13 and 14, in the embodiment shown in Figure 13, the IDT electrode layer 100 includes a busbar 110 and electrode fingers 120. One end of the additional film region 22 near the central region 21 is flush with the edge of the first electrode finger 121 and the edge of the second electrode finger 122, respectively. Specifically, both ends of the central region 21 along a first direction are flush with the edges of the first electrode finger 121 and the second electrode finger 122. The two additional film regions 22 are located between the central region 21 and the connection region 10, and the connection region 10, the additional film regions 22, and the central region 21 are arranged adjacent to each other. The additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100, and is disposed on the additional film region 22, filling the first gap 133.

[0041] Referring to Figures 15 and 16, in the embodiment shown in Figure 15, compared to the embodiment in Figure 13, a dummy electrode finger 130 is also included. One end of the additional film region 22 near the central region 21 is flush with the edge of the first electrode finger 121 and the edge of the second electrode finger 122, respectively. The additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100, and is disposed on the additional film region 22. The additional film 300 fills the second spacer 134 and the dummy electrode finger 130.

[0042] Referring to Figures 17 and 18, in the embodiment shown in Figure 17, the IDT electrode layer 100 includes busbars 110 and electrode fingers 120. An additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100. The additional film region 22 partially overlaps with the busbars 110, that is, the additional film region 22 partially overlaps with the connection region 10, and the additional film region 22 completely covers the first gap 133. Specifically, one end of one additional film 300 extends to a portion under the first busbar 111, and the other end extends to a portion under the second electrode finger 122; another additional film 300 extends to a portion under the second busbar 112, and the other end extends to a portion under the first electrode finger 121. Referring to Figures 19 and 20, the difference from the embodiment shown in Figure 17 is that it also includes dummy electrode fingers 130.

[0043] Referring to Figures 21 and 22, in the embodiment shown in Figure 21, the IDT electrode layer 100 includes a busbar 110 and electrode fingers 120. An additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100. The additional film region 22 partially overlaps with the connection region 10 and completely covers the first gap 133. The edge of the additional film region 22 near the central region 21 is flush with the edges of the first electrode finger 121 and the second electrode finger 122, respectively. Both ends of the central region 21 along a first direction are flush with the edges of the first electrode finger 121 and the second electrode finger 122.

[0044] Referring to Figures 23 and 24, the embodiment shown in Figure 21 differs in that it also includes dummy electrode fingers 130. The additional film 300 is disposed between the piezoelectric substrate 200 and the IDT electrode layer 100. The additional film region 22 partially overlaps with the connection region 10 and completely covers the second gap 134. The edge of the additional film region 22 near the central region 21 is flush with the edges of the first electrode finger 121 and the second electrode finger 122, respectively. Both ends of the central region 21 along the first direction are flush with the edges of the first electrode finger 121 and the second electrode finger 122.

[0045] Referring to Figures 25, 26, 27, and 28, in the embodiments shown in Figures 25 and 27, the IDT electrode layer 100 further includes two dual buses and two connection electrodes 115. The dual buses are located at both ends of the busbar 110 away from the interdigitated region 20. The dual buses include a first dual bus 113 and a second dual bus 114. The first dual bus 113 is disposed at the end of the first busbar 111 away from the second busbar 112, and the second dual bus 114 is disposed at the end of the second busbar 112 away from the first busbar 111. The connection electrode 115 between the first busbar 111 and the first dual bus 113 is correspondingly disposed with the second electrode finger 122, and the connection electrode 115 between the second busbar 112 and the second dual bus 114 is correspondingly disposed with the first electrode finger 121.

[0046] In one embodiment, as shown in Figures 25 and 26, the additional film 300 is disposed on the surface of the IDT electrode layer 100 away from the piezoelectric substrate 200, and on the upper surface of the piezoelectric substrate 200. The additional film region 22 partially overlaps with the connection region 10. One end of one additional film 300 is flush with the edge of the first busbar 111 away from the second busbar 112, and one end of the other additional film 300 is flush with the edge of the second busbar 112 away from the first busbar 111. This embodiment can bidirectionally optimize the dielectric environment and elastic characteristics around the busbar 110 and the electrode finger 120, enhance second-order harmonic suppression and optimize insertion loss, and also make the global acoustic-electric characteristics of the device more uniform, further improving performance consistency and stability.

[0047] In another embodiment, as shown in Figures 27 and 28, the additional film 300 is disposed on the surface of the IDT electrode layer 100 away from the piezoelectric substrate 200, and on the upper surface of the piezoelectric substrate 200. The additional film region 22 partially overlaps with the connection region 10, with one end of the additional film region 22 extending to the end of the connection electrode 115 away from the busbar 110, and the other end extending to the corresponding electrode finger 120.

[0048] In another embodiment, an electronic product is proposed that may include the elastic wave device of any of the above embodiments. Furthermore, it is understood that the foregoing embodiments are merely illustrative examples of the present invention, and the technical solutions of the various embodiments can be arbitrarily combined and used, provided that the technical features do not conflict, the structure is not contradictory, and the inventive purpose is not violated.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An elastic wave device, characterized in that, include: piezoelectric layer; An IDT electrode layer is disposed on the piezoelectric layer. The IDT electrode layer includes two busbars disposed opposite to each other along a first direction, including a first busbar and a second busbar, and the portion between the first busbar and the second busbar is defined as an interdigitated region. Electrode fingers, disposed in the interdigitated region, include a plurality of first electrode fingers and a plurality of second electrode fingers spaced apart along a second direction. The first electrode fingers extend from the first busbar to the second busbar, and the second electrode fingers extend from the second busbar to the first busbar. A first gap exists between the first electrode fingers and the second busbar, and a first gap exists between the second electrode fingers and the first busbar. The interdigitated region includes a central region and an additional film region. The two edges of the central region along the first direction do not exceed the edges of the first electrode fingers and the second electrode fingers on the side away from the busbar. The additional film region is disposed on both sides of the central region and is closer to the busbar than the central region. An additional film is disposed on the piezoelectric substrate and is disposed in the additional film region. The material of the additional film is silicon dioxide, silicon oxide, silicon nitride, HfO2, silicon, resin, PI, or titanium oxide.

2. The elastic wave device as described in claim 1, characterized in that, The additional membrane has a first edge away from the central region along the first direction, and the first edge is flush with the edge of the electrode finger near the first interval.

3. The elastic wave device as described in claim 1, characterized in that, The additional membrane has a first edge extending away from the central region along the first direction, the first edge extending to the first interval.

4. The elastic wave device as described in claim 1, characterized in that, The additional membrane area is located between the central area and the busbar, and the end of the additional membrane furthest from the central area is adjacent to the busbar.

5. The elastic wave device as described in claim 4, characterized in that, The end of the additional film region near the central region is flush with the edge of the first electrode finger and the edge of the second electrode finger, respectively.

6. The elastic wave device as described in claim 1, characterized in that, The additional membrane area partially overlaps with the busbar, and the additional membrane area completely covers the first interval.

7. The elastic wave device as described in claim 6, characterized in that, The edge of the additional film area near the central area is flush with the edges of the first electrode finger and the second electrode finger, respectively.

8. An elastic wave device, characterized in that, include: piezoelectric layer; An IDT electrode layer is disposed on the piezoelectric layer. The IDT electrode layer includes two busbars disposed opposite to each other along a first direction, including a first busbar and a second busbar, and the portion between the first busbar and the second busbar is defined as an interdigitated region. Electrode fingers, disposed in the interdigitated finger region, include a plurality of first electrode fingers and a plurality of second electrode fingers spaced apart along a second direction. The first electrode fingers extend from the first busbar to the second busbar, and the second electrode fingers extend from the second busbar to the first busbar. Dummy electrode fingers include a plurality of first dummy electrode fingers and a plurality of second dummy electrode fingers. The first dummy electrode fingers extend from the first busbar to the side of the second electrode fingers, and the second dummy electrode fingers extend from the second busbar to the side of the first electrode fingers, with a distance between the first dummy electrode fingers and the second electrode fingers. There is a second gap between the second dummy electrode finger and the first electrode finger; the interdigitated region includes a central region and an additional film region, the two edges of the central region along the first direction do not exceed the edges of the first electrode finger and the second electrode finger away from the busbar, the additional film region is disposed on both sides of the central region and is closer to the busbar than the central region; the additional film is disposed on the piezoelectric substrate and is disposed in the additional film region, the material of the additional film is silicon dioxide, silicon oxide, silicon nitride, HfO2, silicon, resin, PI or titanium oxide.

9. The elastic wave device as described in claim 8, characterized in that, The additional membrane has a first edge away from the central region along the first direction, and the first edge is flush with the edge of the electrode finger near the second interval.

10. An elastic wave device as described in claim 8, characterized in that, The additional membrane has a first edge extending away from the central region along the first direction, the first edge extending into the second interval.

11. The elastic wave device as described in claim 1 or 8, characterized in that, The IDT electrode layer also includes two dual buses located on the side of the bus bar away from the interdigitated area and two connection electrodes, the connection electrodes being located between the dual buses and the bus bar.

12. The elastic wave device as described in claim 1 or 8, characterized in that, The additional film is disposed between the piezoelectric substrate and the IDT electrode layer, or the additional film is disposed on the surface of the IDT electrode layer away from the piezoelectric substrate.

13. The elastic wave device as described in claim 1 or 8, characterized in that, The thickness of the additional membrane is less than 0.1λ, where λ is the wavelength of the surface acoustic wave.

14. An electronic product, characterized in that, It includes the elastic wave device as described in any one of claims 1 to 13.

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