Surface acoustic wave transducer and surface acoustic wave device

Abstract

The invention provides a surface acoustic wave transducer and a surface acoustic wave device. In the surface acoustic wave transducer, the density of at least part of the material of the interdigital electrode in the edge region is higher than the density of the material of the interdigital electrode in the main region, so that the acoustic velocity of the edge region is adjusted to be lower than the acoustic velocity of the main region, a working state of a piston mode can be generated, and effective suppression of a transverse mode is realized; and the performance and reliability of the surface acoustic wave device are improved. In specific application, parameters such as materials and thicknesses of the interdigital electrode and all areas, materials of the bus and the like can be flexibly adjusted according to requirements, so that the transverse suppression is realized, the power tolerance of the device is improved, and the electromechanical performance of the surface acoustic wave device is optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of surface acoustic wave devices, and in particular to a surface acoustic wave transducer and a surface acoustic wave device. Background Art

[0002] Surface acoustic wave (SAW) devices usually include a piezoelectric substrate and a surface acoustic wave transducer (IDT) formed on the piezoelectric substrate. The surface acoustic wave transducer IDT is used to achieve sound-to-electric conversion or electric-to-acoustic conversion. It is widely used due to its unique advantages of low conversion loss, flexible design and easy production. It is an important component of various SAW devices. For example, radio frequency filters based on SAW resonators are widely used in wireless communication equipment. With the increase of frequency bands and the limitation of radio frequency spectrum, the requirements for the performance of surface acoustic wave devices are higher. Therefore, it is necessary to optimize surface acoustic wave devices to improve their performance.

[0003] Among them, for surface acoustic wave transducers, due to the characteristics of the surface acoustic wave itself, unnecessary transverse modes will be generated while the main mode is excited. These transverse modes will produce spurious responses, increase the insertion loss of the surface acoustic wave device, reduce the quality factor of the surface acoustic wave device, and affect the performance of the device. In order to reduce the negative impact of the transverse mode, different technologies have been introduced in the past decade, including: hammerhead IDT structure, setting mass load elements, etc. However, these designs generally require higher process resolution, or will lead to a decrease in the overall performance of the resonator, or will increase the physical size of the resonator. Summary of the invention

[0004] The object of the present invention is to provide a surface acoustic wave transducer to achieve transverse mode suppression and improve the overall performance of the device.

[0005] To this end, the present invention provides a surface acoustic wave transducer, comprising: two busbars and a plurality of interdigital electrodes arranged opposite to each other, one end of each interdigital electrode being connected to one of the busbars, and the other end extending in a direction toward the other busbar, and the interdigital electrodes connected to different busbars are arranged crosswise in sequence. Wherein, in the cross-sectional area where the interdigital electrodes are arranged crosswise, the interdigital electrodes have a main area and edge areas located on both sides of the main area, and the density of at least part of the material of the interdigital electrodes in the edge area is higher than the density of the material in the main area.

[0006] Optionally, a metal layer is provided in a main region of the interdigital electrodes, an end block is provided in an edge region of the interdigital electrodes, and a density of the metal layer is lower than a density of the end block.

[0007] Optionally, the main region of the interdigital electrode is further provided with at least one non-metallic layer, the non-metallic layer and the metal layer are alternately stacked along the thickness direction, and the density of the non-metallic layer is not higher than the density of the end block.

[0008] Optionally, the interdigitated electrode includes a main layer and at least one embedded layer, the main layer extends from one end of the interdigitated electrode to the other end, the embedded layer is embedded in the main layer in the main region, and the density of the embedded layer is less than the density of the main layer.

[0009] Optionally, the interdigitated electrode includes two or more embedded layers, and the two or more embedded layers are sequentially stacked in the main layer along the thickness direction.

[0010] Optionally, the at least one embedded layer includes at least one metal layer and / or at least one non-metal layer, and the density of the metal layer and the non-metal layer are both lower than the density of the main layer.

[0011] Optionally, the at least one embedded layer includes at least one metal layer and at least one non-metal layer, and the metal layer and the non-metal layer are alternately stacked along the thickness direction.

[0012] Optionally, the at least one embedded layer includes two or more non-metallic layers, and the two or more non-metallic layers are interspersed in the main layer at intervals along the thickness direction.

[0013] Optionally, a transverse mode suppression unit and a reflection unit are arranged in the edge region, the material density of the transverse mode suppression unit is higher than the material density in the main region, and the reflection unit is arranged at intervals on a side of the transverse mode suppression unit away from the main region.

[0014] Optionally, a metal layer is provided in the main area of ​​the interdigitated electrode, and a first end block is provided in the edge area of ​​the interdigitated electrode, the first end block is connected to the end of the metal layer, and the density of the first end block is higher than the density of the metal layer for forming the transverse mode suppression unit.

[0015] Optionally, a second end block is further provided at an edge region of the interdigitated electrode, and the second end block is spaced apart at a side of the first end block away from the metal layer to form the reflection unit.

[0016] Optionally, the interdigitated electrode includes a main layer and an embedded layer, the main layer extends from one end to the other end of the interdigitated electrode, the embedded layer is stacked on the main layer in the main area, and the end of the main layer is protruding to form the reflection unit.

[0017] Optionally, an end block is further provided in the edge region of the interdigitated electrode, and the end block is connected to the end of the embedded layer.

[0018] Optionally, the material of the interdigital electrodes in the edge region includes copper and / or titanium, and the material of the interdigital electrodes in the main region includes aluminum and / or aluminum oxide.

[0019] Optionally, the material of the busbar is consistent with the material of the edge region of the interdigital electrodes.

[0020] Another object of the present invention is to provide a surface acoustic wave device, which includes the surface acoustic wave transducer as described above.

[0021] In the surface acoustic wave transducer provided by the present invention, by making the density of at least part of the material of the forked-finger electrode in the edge region higher than the material density in the main region, the acoustic wave velocity in the edge region is adjusted to be lower than the acoustic wave velocity in the main region, so that the piston mode working state can be allowed, the transverse mode can be effectively suppressed, and the performance and reliability of the surface acoustic wave device can be improved. For example, a high-density end block can be set in the edge region of the forked-finger electrode, so that the forked-finger electrode forms a transverse composite structure in the edge region and the main region, and the composite structure effectively reduces the acoustic wave velocity in the edge region; or, a low-density film layer can be embedded in the main region of the forked-finger electrode, so that the forked-finger electrode forms a longitudinal composite structure in the main region, and the composite structure effectively increases the acoustic wave velocity in the main region. In this way, effective lateral suppression can be achieved on the basis of avoiding a substantial increase in the physical size of the surface acoustic wave device and ensuring the overall performance of the device.

[0022] In a further solution, it is also helpful to flexibly adjust the material and thickness of each area of ​​the interdigital electrode, the material of the busbar and other parameter settings according to needs, so as to improve the power tolerance of the device and optimize the electromechanical performance of the surface acoustic wave device while achieving lateral suppression. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. 1 is a top view of the surface acoustic wave transducer in the first embodiment of the present invention.

[0024] Figure 2 Schematic cross-sectional view of the surface acoustic wave transducer in the first embodiment of the present invention along the extending direction of the interdigital electrodes.

[0025] Figure 3 It is a simulation diagram of the frequency-admittance of the surface acoustic wave transducer in the first embodiment of the present invention.

[0026] Figure 4 It is a simulation comparison diagram of the piezoelectric coupling coefficient K2 and phase velocity of the surface acoustic wave transducer in the first embodiment of the present invention and the traditional surface acoustic wave transducer.

[0027] Figure 5 It is a top view of the surface acoustic wave transducer in the second embodiment of the present invention.

[0028] Figure 6 It is a schematic cross-sectional view of the surface acoustic wave transducer in the second embodiment of the present invention along the extending direction of the interdigital electrodes.

[0029] Figure 7 Schematic cross-sectional view of the surface acoustic wave transducer in the third embodiment of the present invention along the extending direction of the interdigital electrodes.

[0030] Figure 8 This is a curve showing the thickness ratio of the copper material and the aluminum material in the interdigital electrodes and the resistance of the surface acoustic wave transducer in the third embodiment of the present invention.

[0031] Fig. 9 It is a simulation diagram of frequency-admittance of the surface acoustic wave transducer in the third embodiment of the present invention when the metal layers have different thicknesses.

[0032] Fig.10 A simulation diagram of frequency-admittance of the surface acoustic wave transducer in the third embodiment of the present invention when the edge regions have different lengths.

[0033] Fig.11 Simulation diagram of the piezoelectric coupling coefficient K2 and phase velocity of the surface acoustic wave transducer in the third embodiment of the present invention when the metal layer has different thicknesses.

[0034] Fig.12 Schematic cross-sectional view of the surface acoustic wave transducer in the fourth embodiment of the present invention along the extending direction of the interdigital electrodes.

[0035] Fig.13 Schematic cross-sectional view of the surface acoustic wave transducer in the fifth embodiment of the present invention along the extending direction of the interdigital electrodes.

[0036] Fig.14 Schematic cross-sectional view of the surface acoustic wave transducer in Embodiment 6 of the present invention along the extending direction of the interdigital electrodes.

[0037] Fig.15 Schematic cross-sectional view of the surface acoustic wave transducer along the extension direction of the interdigital electrodes in the seventh embodiment of the present invention.

[0038] Fig.16 Schematic cross-sectional view of the surface acoustic wave transducer in the eighth embodiment of the present invention along the extending direction of the interdigital electrodes.

[0039] Fig.17 Schematic cross-sectional view of the surface acoustic wave transducer in Embodiment 9 of the present invention along the extending direction of the interdigital electrodes.

[0040] Fig.18 This is the stress distribution diagram at the interface of the aluminum material layer and the copper material layer with different thickness ratios in the interdigitated electrode.

[0041] Fig.19 This is a stress distribution diagram at the interface of the aluminum material layer and the copper material layer with different thickness ratios when a titanium material layer is added between the interdigital electrode and the piezoelectric layer.

[0042] The reference numerals are as follows:

[0043] 100-busbar;

[0044] 110-first busbar;

[0045] 120-second busbar;

[0046] 200-interdigitated electrodes;

[0047] 210-first interdigital electrode;

[0048] 220- second interdigital electrode;

[0049] 200a-metal layer;

[0050] 200b-end block;

[0051] 200b'-first end block;

[0052] 200b"-second end block;

[0053] 200c-main body layer;

[0054] 200c'-end of the main body layer;

[0055] 200d-metal layer;

[0056] 200d'- non-metallic layer;

[0057] 300-intersection area;

[0058] 310-main area;

[0059] 320-edge area. DETAILED DESCRIPTION

[0060] The core idea of ​​the present invention is to provide a novel surface acoustic wave transducer having a composite structure capable of effectively achieving transverse mode suppression and reducing the stray response of the surface acoustic wave device.

[0061] Specifically, the surface acoustic wave transducer provided by the present invention comprises two busbars and a plurality of interdigital electrodes arranged opposite to each other, one end of each interdigital electrode is connected to one of the busbars, and the other end extends in a direction toward the other busbar, and the interdigital electrodes connected to different busbars are arranged crosswise in sequence. In the cross region where the interdigital electrodes are arranged crosswise, the interdigital electrodes have a main region and edge regions located on both sides of the main region, and the density of at least part of the material of the interdigital electrodes in the edge region is higher than the material density in the main region.

[0062] Specifically, by making the density of at least part of the material in the edge area of ​​the forked electrode higher than the material density in the main area, the acoustic wave velocity corresponding to at least this part of the high-density material in the edge area is adjusted to be lower than the acoustic wave velocity in the main area, thereby forming a piston mode, achieving effective suppression of the transverse mode, and improving the performance and reliability of the surface acoustic wave device.

[0063] In an optional solution provided by the present invention, different materials can be combined in a transverse composite manner to form the interdigital electrodes of the surface acoustic wave transducer. For example, the edge region of the interdigital electrode can be provided with an end block of a high-density material, and the main region of the interdigital electrode can be provided with a metal layer of a low-density material. That is, the end block and the metal layer are laterally connected (specifically, they are laterally connected along the length direction of the interdigital electrode). At this time, even if the end size of the edge region is not adjusted and no additional mass load element is provided, it is still possible to achieve that the acoustic wave velocity of the edge region is lower than the acoustic wave velocity of the main region, allowing the piston mode working state and avoiding the increase in the physical size of the surface acoustic wave device. It can be understood that in this solution, a high-density material is provided in the edge region to reduce the acoustic wave velocity of the edge region, so as to allow the piston mode working state.

[0064] In another optional solution provided by the present invention, different materials can be combined in a longitudinal composite manner in the main area of ​​the interdigitated electrode. For example, the interdigitated electrode can include a main layer of high-density material and at least one embedded layer of low-density material, the main layer extends from one end of the interdigitated electrode to the other end, and the embedded layer is embedded in the main layer in the main area. That is, in the main area, the embedded layer is stacked above or below the main layer, so that the material density of the interdigitated electrode in the main area is lower than the material density of the edge area, and because the embedded layer is embedded in the main layer, it will not cause a significant increase in the physical size of the resonator. It can be understood that in this solution, a low-density material is embedded in the main area to increase the speed of sound waves in the main area, so as to allow the piston mode working state.

[0065] For the solution of longitudinally compounding different material layers in the main region, the longitudinally compounded embedded layer may include a metal layer; and / or, the longitudinally compounded embedded layer may include a non-metal layer, the material density of the non-metal layer is not higher than the material density of the edge region. In addition, in other optional solutions, different materials are combined in a combination of transverse compounding and longitudinal compounding to form the interdigital electrodes of the surface acoustic wave transducer.

[0066] In another optional solution provided by the present invention, a high-density material is provided in the edge region of the interdigital electrode to form a transverse mode suppression unit for realizing transverse mode suppression, and a reflection unit may also be provided in the edge region of the interdigital electrode, and the reflection unit is located on the side of the transverse mode suppression unit away from the main region. In this way, not only transverse mode suppression can be realized, but also energy confinement can be better realized and scattering loss can be reduced.

[0067] The surface acoustic wave transducer and surface acoustic wave device proposed in the present invention are further described in detail in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be more clear. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, relative terms such as "above", "below", "top", "bottom", "above" and "below" shown in the accompanying drawings can be used to describe the relationship between various elements. These relative terms are intended to cover different orientations of elements other than the orientations depicted in the accompanying drawings. For example, if the device is inverted relative to the view in the accompanying drawings, an element described as being "above" another element will now be below the element.

[0068] Embodiment 1

[0069] Figure 1 is a top view of the surface acoustic wave transducer in the first embodiment of the present invention, Figure 2 It is a schematic cross-sectional view of the surface acoustic wave transducer along the aa' direction in the first embodiment of the present invention.

[0070] First reference Figure 2 As shown, the surface acoustic wave transducer is specifically formed on a piezoelectric layer 400, and the material of the piezoelectric layer 400 includes but is not limited to LiTaO (lithium tantalate), LiNbO (lithium niobate), quartz, etc. in various cuts. In addition, the surface acoustic wave transducer may also be covered with a passivation layer (not shown in the figure), and the material of the passivation layer includes, for example, silicon oxide.

[0071] Then combine Figure 1 and Figure 2As shown, the surface acoustic wave transducer includes: two busbars 100 arranged opposite to each other and a plurality of interdigitated electrodes 200, one end of each interdigitated electrode 200 is connected to one of the busbars, and the other end extends in a direction toward the other busbar, and the interdigitated electrodes 200 connected to different busbars 100 are arranged crosswise in sequence.

[0072] Specific reference Figure 1 As shown, two busbars 100 arranged opposite to each other are respectively a first busbar 110 and a second busbar 120, and a plurality of interdigital electrodes 200 include a first interdigital electrode 210 and a second interdigital electrode 220. One end of the first interdigital electrode 210 is connected to the first busbar 110, and the other end of the first interdigital electrode 210 extends toward the second busbar 120; one end of the second interdigital electrode 220 is connected to the second busbar 120, and the other end of the second interdigital electrode 220 extends toward the first busbar 110. The first busbar 110 and the second busbar 120 are arranged along a first direction (e.g. Figure 1 The first interdigitated electrodes 210 and the second interdigitated electrodes 220 extend along the second direction (eg, Figure 1 Also, the region where the first interdigital electrodes 110 and the second interdigital electrodes 120 are cross-arranged may be defined as a cross region 300, in which each interdigital electrode 200 has a main region 310 and edge regions 320 located on both sides of the main region 310.

[0073] Furthermore, the material density of each interdigital electrode 200 in the edge region 320 is higher than that in the main region 310. In this way, the acoustic wave velocity in the edge region 320 is lower than that in the main region 310, thereby forming a piston mode, achieving effective suppression of the transverse mode, and improving the performance and reliability of the surface acoustic wave device. On this basis, a material with good adhesion, high conductivity, and low mechanical loss can be selected for the main region 310 of the interdigital electrode 200, and the main region 310 is optimized to achieve transverse mode suppression on the basis of ensuring good power tolerance.

[0074] In this embodiment, the edge region 320 and the main region 310 of the interdigital electrode 200 are made of different materials and are combined in a transversely connected manner to form the interdigital electrode 200. Figure 2As shown, the edge region 320 of the interdigital electrode 200 is provided with an end block 200b of a high-density material, and the main region 310 of the interdigital electrode 200 is provided with a metal layer 200a of a low-density material, wherein the density of the end block 200b is higher than the density of the metal layer 200a. Specifically, the metal layer 200a extends along the extension direction of the interdigital electrode, and the end blocks 200b are provided on the outer sides of the two ends in the extension direction of the metal layer 200a, and the end blocks 200b are laterally connected to the end side walls of the metal layer 200a. In this embodiment, the end block 200b and the metal layer 200a are directly formed on the piezoelectric layer 400, and the thickness of the end block 200b can be not greater than the thickness of the metal layer 200a. For example, the thickness of the end block 200b can be consistent with the thickness of the metal layer 200a, and at this time, the top surfaces of the end block 200b and the metal layer 200a are correspondingly flush.

[0075] For example, the metal layer 200a can be made of aluminum (Al), and the material of the end block 200b can be made of a metal material with a higher density, such as copper (Cu), platinum (Pt), etc. Alternatively, the material of the end block 200b can also be made of a high-density non-metallic material, such as aluminum oxide. In a specific example, the end block 200b can be formed of copper material. Specifically, the density ρ of the copper material is about 8900 kg / m3, and the density ρ of the aluminum material is about 2700 kg / m3. At this time, the acoustic wave velocity in the aluminum material can reach 6320 m / s, while the acoustic wave velocity in the copper material is lower, which is about 4700 m / s. Therefore, by setting the material of the edge region 320 of the interdigital electrode 200 to copper material and setting the material of the main region 310 to aluminum material, the acoustic wave velocity of the edge region 320 is lower than the acoustic wave velocity of the main region 310, allowing the piston mode to work, and achieving the effect of transverse mode suppression.

[0076] Furthermore, for surface acoustic wave devices in the medium and high frequency bands, the thickness of the metal layer 200a can be controlled to be 20nm-200nm; and for surface acoustic wave devices in the low frequency band, the thickness of the metal layer 200a can be controlled to be between 100nm and 800nm, for example. In addition, in order to achieve better transverse mode suppression, the thickness of the metal layer 200a can be further adjusted according to the specific application frequency band, the specific material of the metal layer 200a, the specific length of the end block 200b, etc.; for example, for surface acoustic wave devices in the medium and high frequency bands, and the metal layer 200a using aluminum material, the length of the end block 200b is 0.5 times the wavelength, the thickness of the metal layer 200a can be controlled to be, for example, below 120nm, and more specifically, the thickness of the metal layer 200a can be between 40nm and 100nm.

[0077] Combine the following Figure 3The simulation diagram of the frequency-admittance of the surface acoustic wave transducer in this embodiment is shown to further verify the transverse mode suppression performance of the surface acoustic wave transducer in this embodiment and the thickness optimization of the metal layer 200a in the main area 310. The simulation model is, for example, a characteristic analysis performed by the finite element method (Finite Element Method, FEM) based on the parameter that the length of the end block 200b of the edge area 320 along the extension direction of the interdigital electrode is 0.5 times the wavelength (for example, for a surface acoustic wave device with a wavelength of 4μm, 0.5 times the wavelength is approximately 2μm). Figure 3 It can be clearly seen that the corresponding admittance curves of the transducer under the metal layer 200a of different thicknesses, wherein the parasitic resonance peak is significantly reduced when the thickness of the metal layer 200a is less than or equal to 120nm, indicating that the corresponding surface acoustic wave transducer can effectively suppress the transverse mode, which is beneficial to improve the Q value of the surface acoustic wave device. In particular, when the thickness of the metal layer 200a is within the range of 40nm-100nm, the corresponding admittance curve has the least parasitic resonance peak, reflecting the optimal choice of thickness.

[0078] It should also be noted that the surface acoustic wave transducer provided in this embodiment can avoid affecting other performances on the basis of achieving transverse mode suppression. The following is verified by simulating the piezoelectric coupling coefficient K2 and phase velocity of the traditional surface acoustic wave transducer and the surface acoustic wave transducer in this embodiment.

[0079] Figure 4 : is a simulation comparison diagram of the surface acoustic wave transducer in this embodiment and the traditional surface acoustic wave transducer with respect to the piezoelectric coupling coefficient K2 and the phase velocity, Figure 4 The middle curve PV_1 represents the phase velocity curve of the traditional surface acoustic wave transducer. Figure 4 The middle curve PV_2 represents the phase velocity curve of the surface acoustic wave transducer in this embodiment. By comparing the phase velocity curve PV_1 and the phase velocity curve PV_2, it can be found that the phase velocity of the surface acoustic wave transducer in this embodiment is almost the same as the phase velocity of the traditional surface acoustic wave transducer. The reason is that this embodiment only optimizes the edge area 320 of the forked electrode 200 (that is, the edge area 320 of the forked electrode 200 is set as the end block 200b of high-density material), and the main area 310 can remain unchanged, thereby ensuring the main performance of the device.

[0080] Next reference Figure 4 As shown, Figure 4 The middle curve K2_1 represents the piezoelectric coupling coefficient K2 of the traditional surface acoustic wave transducer. Figure 4The middle curve K2_2 represents the piezoelectric coupling coefficient K2 of the surface acoustic wave transducer in this embodiment. By comparison, it can be found that the piezoelectric coupling coefficient K2 of the surface acoustic wave transducer in this embodiment is slightly reduced, especially when the electrode thickness increases, the piezoelectric coupling coefficient K2 decreases accordingly. However, when the electrode thickness is less than 100nm, the piezoelectric coupling coefficient K2 of the surface acoustic wave transducer in this embodiment is only reduced by about 0.1% at most relative to the piezoelectric coupling coefficient K2 of the traditional surface acoustic wave transducer. Therefore, by reasonably adjusting the thickness of the electrode, the piezoelectric coupling coefficient K2 of the surface acoustic wave transducer can still be effectively guaranteed.

[0081] Embodiment 2

[0082] Different from the first embodiment, in this embodiment, the busbar and the portion of the interdigital electrode connected to the busbar can be made of the same material as the edge region of the interdigital electrode. On this basis, materials with high electrical conductivity and high thermal conductivity can be selected and applied to the busbar and the interdigital electrode in other regions except the main region, so that the device has better performance and conductivity.

[0083] Figure 5 is a top view of the surface acoustic wave transducer in the second embodiment of the present invention, Figure 6 for Figure 5 The schematic cross-sectional view of the surface acoustic wave transducer along the aa' direction in the second embodiment of the present invention is shown. Figure 5 and Figure 6 As shown, the main area 310 of the interdigital electrode 200 in this embodiment is provided with a metal layer 200a of low density material, and the edge area 320 of the interdigital electrode 200 is provided with an end block 200b of high density material. Similar to the first embodiment, the end block 200b in this embodiment is also arranged outside the end of the metal layer 200a in its extension direction, and the end block 200b is laterally connected to the end side wall of the metal layer 200a. In addition, the thickness of the end block 200b can also be made consistent with the thickness of the metal layer 200a, and in this case, the top surface of the end block 200b and the metal layer 200a are made flush.

[0084] Different from the first embodiment, in this embodiment, the connection portion of the interdigital electrode 200 connected to the busbar 100 can also be made of high-density material, and the busbar 100 also uses high-density material, wherein the high-density material used for the connection portion of the interdigital electrode 200 and the busbar 100 can be the same as the material of the end block 200b.

[0085] That is, the high-density material applied to the end block 200b can be extended to the connection part of the interdigital electrode 200 and the busbar 100. It can be considered that in this embodiment, a low-density material (such as an aluminum material) is used in the main area 310 of the interdigital electrode 200, and a high-density material (such as a copper material) is used in other areas of the interdigital electrode 200 and the busbar 100. In a specific example, the busbar 100 and the interdigital electrode 200 can be formed based on the same high-density material, and then the high-density material in the main area 310 of the interdigital electrode 200 is replaced by the metal layer 200a of the low-density material.

[0086] In one example, the high-density material used from the edge region 320 of the interdigital electrode 200 to the busbar 100 includes, for example, copper (Cu), so that on the basis of achieving transverse mode suppression, the insertion loss can be further reduced and a lower resistance can be achieved. Specifically, the copper (Cu) material has good thermal conductivity and electrical conductivity, so expanding the application of the copper material to the busbar 100 is conducive to reducing the insertion loss and achieving a lower resistance, so the surface acoustic wave transducer in this embodiment can further optimize the overall performance of the device.

[0087] It should be noted that the parameter settings of the metal layer 200 a of the interdigital electrode 200 in this embodiment may refer to the parameter settings of the metal layer 200 a of the interdigital electrode 200 in the first embodiment.

[0088] Embodiment 3

[0089] Different from the first and second embodiments, in this embodiment, a low-density material is embedded in the main region to increase the acoustic wave velocity of the main region, thereby achieving the effect of transverse mode suppression. That is, in the main region of the interdigital electrode, a low-density material can be stacked on a high-density material in a longitudinal composite manner, so as to increase the overall acoustic wave velocity of the main region.

[0090] Figure 7 FIG. 4 is a schematic cross-sectional view of the surface acoustic wave transducer in the third embodiment of the present invention along the extending direction of the interdigital electrodes. Figure 7 As shown, the interdigitated electrode 200 in this embodiment includes a main layer 200c of a high-density material and at least one embedded layer of a low-density material (eg Figure 7The main body layer 200c extends from one end of the interdigital electrode 200 to the other end, and the embedded layer is embedded in the main body layer 200c in the main region 310. That is, the embedded layer and the main body layer 200c are stacked in the main region 310 of the interdigital electrode 200. In this embodiment, the embedded layer is stacked above the main body layer 200c as an example. However, in other embodiments, the embedded layer can also be stacked below or inside the main body layer 200c. In addition, at least two embedded layers can be provided in the main region 310, and at least two embedded layers are interspersed in the main body layer 200c at intervals along the thickness direction.

[0091] Furthermore, the top surface of the embedded layer in the main region 310 and the top surface of the main layer 200c in the edge region 320 can be made flush, that is, the thickness of the region where the film layer is embedded and the thickness of the region where the film layer is not embedded can be kept consistent. In this embodiment, the total thickness of the metal layer 200d and the main layer 200c in the main region 310 is the same as the thickness of the main layer 200c in the edge region 320.

[0092] The main body layer 200c may be made of a high-density metal material, such as copper (Cu); the embedded layer in this embodiment includes a metal layer 200d, which specifically uses a low-density metal material, such as aluminum (Al). It should be noted that the main body layer 200c and the metal layer 200d in this embodiment are stacked in the main region 310, so that the main body layer 200c and the metal layer 200d are easy to form an alloy at the interface, which is beneficial to improving the power tolerance of the device.

[0093] Furthermore, the busbar 100 may also be made of a high-density material, and the high-density material used may be consistent with the material of the main layer 200c. That is, the busbar 100 and the main layer 200c may be made of the same high-density metal material, such as copper material (Cu). As mentioned above, the copper material (Cu) has good thermal conductivity and electrical conductivity, which is conducive to reducing the insertion loss of the device and achieving lower resistance, thereby further optimizing the overall performance of the device and improving the power tolerance of the device. In this embodiment, by selecting a material with high thermal conductivity and high electrical conductivity to be applied to the main layer 200c, the main layer 200c is formed in the edge region 320 and the main region 310 of the interdigitated electrode 200, and the high thermal conductivity and high electrical conductivity of the main region 310 are correspondingly achieved. Therefore, in a specific application, the thickness ratio of the main layer 200c and the embedded layer (the metal layer 200d in this embodiment) in the main region 310 can be adjusted according to the needs to balance the transverse mode suppression performance and resistance loss of the device.

[0094] Figure 8 : is a curve showing the thickness ratio of the copper material and the aluminum material in the interdigital electrodes and the resistance of the surface acoustic wave transducer in the third embodiment of the present invention. Figure 8 As shown, due to the high electrical conductivity of copper material, as the thickness of copper material increases, the overall resistance of the interdigital electrode decreases accordingly. Compared with the case where all aluminum materials are used, the resistivity can be reduced by 60% when all copper materials are used. Therefore, in order to reduce the resistance loss of the interdigital electrode, the thickness of the copper material layer can be appropriately increased, for example, the thickness of the copper material can reach 40%-80% of the total thickness of the electrode.

[0095] In a specific example, the thickness of the embedded layer (the metal layer 200d in this embodiment) can be set in the main region 310 of the interdigital electrode 200 to be 20%-40% of the total thickness, so that the main material in the main region 310 is still a material with high thermal conductivity and high electrical conductivity (such as copper material), so the interdigital electrode 200 can still maintain a high electrical conductivity. For example, if the total thickness of the interdigital electrode 200 is 300nm, the thickness of the embedded layer (the metal layer 200d in this embodiment) can be set to 60nm-120nm, and the thickness of the main layer 200c in the main region 310 is 180nm-240nm.

[0096] Combine the following Fig. 9 The simulation diagram of the surface acoustic wave transducer in this embodiment about frequency-admittance is shown to further verify the transverse mode suppression performance of the surface acoustic wave transducer in this embodiment and the thickness optimization of the metal layer 200d in the main area 310. The simulation model is, for example, a characteristic analysis performed by the finite element method (Finite Element Method, FEM) based on the reference that the total thickness of the interdigital electrodes is fixed to 300nm. Fig. 9 It can be clearly seen that the corresponding admittance curves of the transducers with metal layers (aluminum material layers) of different thicknesses, where the parasitic resonance peak is significantly reduced when the thickness of the metal layer 200d is 60nm-100nm, indicating that the corresponding surface acoustic wave transducer can effectively suppress the transverse mode, which is beneficial to improving the Q value of the surface acoustic wave device. In particular, when the thickness of the metal layer 200d is within the range of 80nm-100nm, the corresponding admittance curve has the least parasitic resonance peak, reflecting the optimal choice of thickness.

[0097] In addition, the length of the edge region 320 of the interdigital electrode 200 can also be adjusted accordingly. In a specific example, the length of the edge region 320 along the extension direction of the interdigital electrode can be less than 0.3 times the wavelength. For example, for a surface acoustic wave device with a wavelength of 4μm, 0.3 times the wavelength is approximately 1.2μm.

[0098] Combine the following Fig.10The simulation diagram of the surface acoustic wave transducer in this embodiment about frequency-admittance is shown. In this simulation model, the length of the edge region 320 is mainly optimized and verified. This simulation model is, for example, a characteristic analysis based on the reference that the total thickness of the interdigital electrodes is fixed to 300nm by using the finite element method (Finite Element Method, FEM). Fig.10 It can be clearly seen that the corresponding admittance curves of the transducers with edge regions 320 of different lengths are significantly reduced when the length of the edge region 320 is 0.6μm-1.2μm, indicating that the corresponding surface acoustic wave transducer can effectively suppress the transverse mode, which is beneficial to improving the Q value of the surface acoustic wave device. In particular, when the length of the edge region 320 is 0.6μm, the corresponding admittance curve has the least parasitic resonance peak and has a nearly complete transverse suppression capability, reflecting the optimal choice of the length of the edge region 320.

[0099] Therefore, by optimizing the length of the edge region 320 of the interdigital electrode 200 and the thickness of the embedded layer (the metal layer 200d in this embodiment) in the main region 310, the lateral suppression capability can be improved to a greater extent.

[0100] In a further solution, the piezoelectric coupling coefficient K2 and the phase velocity of the surface acoustic wave transducer may be combined to optimize the parameters of the metal layer 200 d in the main region 310 of the interdigital electrode 200 . Fig.11 : is a simulation diagram of the piezoelectric coupling coefficient K2 and the phase velocity of the surface acoustic wave transducer in this embodiment when the metal layer 200d has different thicknesses, as shown in FIG. Fig.11 As shown, as the thickness of the metal layer 200d (for example, the aluminum material layer) increases, that is, the thickness of the metal layer 200d of the low-density material gradually increases, and at the same time, the mass load of the main area 310 decreases, so its phase velocity PV will increase accordingly with the increase in the thickness of the metal layer 200d. In addition, the piezoelectric coupling coefficient k2 of the surface acoustic wave device reaches a maximum value when the thickness of the metal layer 200d is approximately 80nm to 100nm, so the thickness of the metal layer 200d can be set to 80nm to 100nm to balance the device's piezoelectric coupling coefficient k2 and transverse mode suppression capabilities.

[0101] Embodiment 4

[0102] Different from the third embodiment, the embedded layer in the main region of the interdigitated electrode in this embodiment may also include a non-metallic layer, and the density of the non-metallic layer is less than the density of the main layer. Specifically, the embedded layer in the main region may include a metal layer and a non-metallic layer; or, the embedded layer in the main region may also include only a non-metallic layer. In this embodiment, the embedded layer includes only a non-metallic layer as an example for description.

[0103] Fig.12 FIG. 4 is a schematic cross-sectional view of the surface acoustic wave transducer in the fourth embodiment of the present invention along the extending direction of the interdigital electrodes. Fig.12 As shown, the interdigitated electrode 200 includes a main body layer 200c and at least one embedded layer, the embedded layer includes a non-metal layer 200d', and the density of the non-metal layer 200d' is less than the density of the main body layer 200c. Similar to the third embodiment, in this embodiment, the top surface of the non-metal layer 200d' in the main area 310 can be flush with the top surface of the main body layer 200c in the edge area 320, that is, the total thickness of the non-metal layer 200d' and the main body layer 200c in the main area 310 is the same as the thickness of the main body layer 200c in the edge area 320. The material of the main layer 200c is specifically a high-density metal material, such as copper material (Cu); the material of the non-metal layer 200d' is specifically a low-density non-metal material, such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (SiN) or diamond-like carbon material (DLC).

[0104] Specifically, a low-density non-metallic layer 200d' is used to increase the acoustic surface wave velocity of the main region, so that the structure allows the working state of transverse mode suppression. However, the non-metallic material used in the interdigital electrode 200 may reduce the conductivity of the electrode. For this reason, for example, the thickness of the non-metallic layer 200d' can be controlled to be less than 85% of the total thickness of the electrode; for example, the total thickness of the interdigital electrode 200 is 300nm, and the thickness of the non-metallic layer 200d' can be controlled to be less than or equal to 250nm, so as to achieve transverse mode suppression on the basis of ensuring the conductivity of the interdigital electrode 200.

[0105] Embodiment 5

[0106] Different from the fourth embodiment, at least one embedded layer in this embodiment includes two or more non-metallic layers. Therefore, compared with the single non-metallic layer with a larger thickness in the third embodiment, the thickness of each non-metallic layer in this embodiment is smaller, and each non-metallic layer with a smaller thickness can be interspersed in the main layer along the thickness direction.

[0107] Fig.13 FIG. 4 is a schematic cross-sectional view of the surface acoustic wave transducer in the fifth embodiment of the present invention along the extending direction of the interdigital electrodes. Fig.13As shown, the interdigitated electrode 200 in this embodiment has at least two non-metallic layers 200d' disposed in the main region 310, and the at least two non-metallic layers 200d' are interspersed in the main layer 200c along the thickness direction. Specifically, in ultra-high frequency applications, considering the skin effect, using multiple non-metallic layers 200d' with smaller thickness is beneficial to reducing resistance loss, maintaining good electrode conductivity, and improving the power tolerance of the device.

[0108] In a specific example, the total thickness of the plurality of non-metallic layers 200d' and the main layer 200c in the main region 310 may also be consistent with the thickness of the main layer 200c in the edge region 320. In this embodiment, the non-metallic layer 200d' is arranged at the top layer in the main region 310, and the top surface of the non-metallic layer 200d' can be flush with the top surface of the main layer 200c in the edge region 320. However, in other embodiments, the plurality of non-metallic layers 200d' can be buried in the main layer 200c, and the main layer 200c in the main region 310 is exposed at the top layer, and the top surface of the main layer 200c in the main region 310 can be flush with the top surface of the main layer 200c in the edge region 320.

[0109] Embodiment 6

[0110] In this embodiment, a low-density metal layer and a non-metal layer are disposed in the main region of the interdigital electrode, wherein the metal layer and the non-metal layer may be arranged alternately along the thickness direction.

[0111] In a specific example, only low-density metal layers and non-metal layers may be provided in the main region of the interdigital electrode, and high-density metal ends may be provided in the edge region of the interdigital electrode; for example, only aluminum metal layers and aluminum oxide layers may be provided in the main region of the interdigital electrode, and copper end blocks may be provided in the edge region of the interdigital electrode. Alternatively, in other examples, in addition to low-density metal layers and non-metal layers, the main region of the interdigital electrode also has a high-density metal layer consistent with the material of the edge region of the interdigital electrode; for example, the interdigital electrode has a main layer of copper material that runs through the entire length of the electrode, and an aluminum metal layer and an aluminum oxide layer embedded in the main layer in the main region.

[0112] Fig.14 FIG. 1 is a cross-sectional schematic diagram of a surface acoustic wave transducer in Embodiment 6 of the present invention along the extending direction of the interdigital electrodes. Fig.14It is listed that the interdigital electrode 200 includes a main body layer 200c of a high-density material and at least two embedded layers of a low-density material, the main body layer 200c extends from one end of the interdigital electrode 200 to the other end, and the at least two embedded layers include a metal layer 200d and a non-metal layer 200d' of a low-density material, wherein the metal layer 200d and the non-metal layer 200d' are arranged alternately along the thickness direction. The material of the main body layer 200c includes, for example, copper material (Cu); and the material of the metal layer 200d includes, for example, aluminum material (Al), and the material of the non-metal layer 200d' includes, for example, aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (SiN) or diamond-like carbon material (DLC), etc.

[0113] In one example, the material of the non-metal layer 200d' includes metal oxide. Based on this, the non-metal layer 200d' can be obtained by, for example, oxidizing the metal layer 200d below it. For example, the material of the metal layer 200d includes aluminum, and the non-metal layer 200' of aluminum oxide material can be obtained by oxidizing the metal layer 200d.

[0114] The surface acoustic wave transducer provided in this embodiment can more flexibly adjust the film layer arrangement in the main region of the interdigital electrode, thereby achieving transverse mode suppression while also effectively improving the conductivity of the electrode.

[0115] It should be noted that, in the present embodiment, the total thickness of the non-metal layer 200d', the metal layer 200d and the main layer 200c in the main region 310 is slightly greater than the thickness of the main layer 200c in the edge region 320, thereby making the film layer of the main region 310 protrude relative to the film layer of the edge region 320. However, it should be recognized that, in other embodiments, the total thickness of the non-metal layer 200d', the metal layer 200d and the main layer 200c in the main region 310 may also be consistent with the thickness of the main layer 200c in the edge region 320, thereby making the top surface of the main region 310 flush with the top surface of the edge region 320.

[0116] Embodiment 7

[0117] Different from the sixth embodiment, in this embodiment, at least two low-density metal layers and at least one non-metal layer are provided in the main region of the interdigitated electrode, and the metal layers and the non-metal layers may be arranged alternately along the thickness direction.

[0118] Fig.15 FIG. 4 is a schematic cross-sectional view of the surface acoustic wave transducer in the seventh embodiment of the present invention along the extending direction of the interdigital electrodes. Fig.15As shown, the interdigitated electrode 200 includes a main body layer 200c, on which at least two metal layers 200d of low-density material and at least one non-metal layer 200d' are arranged in the main region, the metal layers 200d and the non-metal layers 200d' are arranged alternately, and each non-metal layer 200d' may also be provided with metal layers 200d on both the upper and lower sides.

[0119] In a specific example, the thickness of the main layer 200c in the edge region 320 may also be made not greater than the total thickness of the film layers in the main region 310 (i.e., the total thickness of the metal layer 200d, the non-metal layer 200d' and the main layer 200c). In this embodiment, the total thickness of each film layer in the main region 310 is consistent with the thickness of the main layer 200c in the edge region 320, thereby making the top surface of the main region 310 flush with the top surface of the edge region 320.

[0120] In this embodiment, the material of the non-metal layer 200d' may also include metal oxide, and may also be obtained by oxidizing the metal layer 200d below it. For example, in one example, a metal layer may be deposited in the main region of the main body layer 200c first, and then a non-metal layer of metal oxide material may be formed on the top surface of the current metal layer by oxidation, and then a metal layer may be deposited on the current non-metal layer, and then a non-metal layer of metal oxide material may be formed on the top surface of the current metal layer by oxidation, and this cycle may be repeated to obtain multiple layers of alternately stacked metal layers and non-metal layers.

[0121] Embodiment 8

[0122] Different from the above-mentioned embodiment, the surface acoustic wave transducer in this embodiment is provided with not only a transverse mode suppression unit but also a reflection unit in the edge region of the interdigital electrode, wherein the material density of the transverse mode suppression unit is higher than the material density in the main region, and the reflection unit is arranged at intervals on the side of the transverse mode suppression unit away from the main region. In this way, not only the transverse mode suppression can be performed, but also the energy confinement can be better realized and the scattering loss can be reduced.

[0123] Fig.16 FIG. 4 is a schematic cross-sectional view of the surface acoustic wave transducer in the eighth embodiment of the present invention along the extending direction of the interdigital electrodes. Fig.16As shown, in the interdigitated electrode 200 of the surface acoustic wave transducer, a high-density first end block 200b' is arranged in the edge region 320 thereof for forming a transverse mode suppression unit, and a second end block 200b' is also arranged in the edge region 320. The second end block 200b' is arranged at intervals on the side of the first end block 200b' away from the main region 310 for forming a reflection unit. In the present embodiment, a metal layer 200a is arranged in the main region 310 of the interdigitated electrode 200 and is laterally joined to the first end block 200b' of the edge region 320. In a specific example, the material used for the first end block 200b' can be the same as the material of the second end block 200b', for example, both include copper material or titanium material.

[0124] Embodiment 9

[0125] Different from the eighth embodiment, the interdigitated electrodes in this embodiment are stacked in a longitudinal composite manner using different materials in the main region, and end blocks of high-density materials are also provided in the edge region to form a transverse mode suppression unit, and a reflection unit is also provided in the edge region.

[0126] Fig.17 FIG. 4 is a schematic cross-sectional view of the surface acoustic wave transducer in the ninth embodiment of the present invention along the extending direction of the interdigital electrodes. Fig.17 As shown, the interdigitated electrode 200 in this embodiment includes a main body layer 200c, which extends from one end of the interdigitated electrode to the other end and runs through the entire interdigitated electrode along the length direction. The interdigitated electrode 200 also includes an embedded layer (for example, a metal layer 200d in this embodiment), and the metal layer 200d is stacked on the main layer 200c in the main area. Specifically, the main layer 200c is formed with a groove in the main area, and the metal layer 200d is formed in the groove. Further, a first end block 200b' is also provided in the edge area 320, and the first end block 200b' is connected to the end of the embedded layer. For example, the first end block 200b' can be laterally joined to the metal layer 200d, or the metal layer 200d can be extended to the edge area 320, and the first end block 200b' is formed on the end of the metal layer 200d.

[0127] In this embodiment, a metal layer 200d of low-density material is provided in the main region 310 to increase the acoustic wave velocity in the main region 310, and an end block 200b of high-density material is provided in the edge region 320, thereby reducing the acoustic wave velocity in the edge region 320. In this way, the acoustic wave velocity in the main region 310 can be made higher than the acoustic wave velocity in the edge region 320 to a greater extent, thereby further optimizing the lateral mode suppression capability of the device.

[0128] Continue to refer Fig.17As shown, the main body layer 200c in this embodiment is protrudingly disposed at the end 200c' of the edge region 320, so that the end 200c' of the main body layer 200c can be directly used to form a reflection unit for realizing energy confinement and reducing scattering loss.

[0129] In the surface acoustic wave transducer in the above embodiment, it can be achieved that the material density of the edge region 320 of the forked electrode 200 is higher than the material density of the main region 310, so that the sound wave velocity of the edge region 320 can be lower than the sound wave velocity of the main region 310, thereby forming a piston mode and achieving effective suppression of the transverse mode.

[0130] In addition, for surface acoustic wave devices, power tolerance is also a key parameter. When high power is applied to the device, the device is prone to overall performance degradation or even damage under the action of large power. Therefore, it is necessary to improve the problem of device failure due to high power in order to improve the power tolerance of surface acoustic wave devices and optimize the overall performance of surface acoustic wave devices. Among them, there are many factors that cause the device to fail easily under high power and affect its power tolerance, including resistance and acoustic loss and poor thermal conductivity as mentioned above, as well as higher stress distribution in the electrode. Specifically, the mechanical properties in the electrode structure have a great influence on the power tolerance of the device. High stress can easily cause the microstructure in the electrode structure to be destroyed, especially at the interface, where cavities may be generated, crystals and grain structures may be destroyed, etc. By reducing the stress in the electrode structure, the probability of defects such as dislocations and cavities can be reduced, thereby improving the power tolerance of the device.

[0131] Compared with the traditional interdigital electrodes formed by a single material, the interdigital electrodes formed by combining different materials in a longitudinal composite manner in the main region 310 in the present invention are also beneficial to reducing the internal stress of the electrode, or the internal stress of the electrode can be optimized by adjusting the various material layers stacked. For example, in the third embodiment, a metal layer 200d and a main layer 200c are stacked in the main region of the interdigital electrode 200. For this, the thickness ratio of the metal layer 200d and the main layer 200c in the main region 310 can be adjusted to further reduce the internal stress of the interdigital electrode 200 and improve the power tolerance of the device. Specifically, for the main layer 200c of copper material and the metal layer 200d of aluminum material, for example, the thickness ratio of the main layer 200c to the metal layer 200d can be set to 1:2 to 2:1.

[0132] Taking the example of the main region of the interdigitated electrode being stacked with a copper material layer and an aluminum material layer, a simplified mechanical finite element model simulation is performed to understand the stress distribution of the electrode structure under different metal ratios. Fig.18is the stress distribution diagram at the interface of the aluminum material layer and the copper material layer with different thickness ratios in the interdigital electrode, where Fig.18 The abscissa represents the stress distribution from one opposite edge to the other edge along the width direction of the interdigital electrode, and Fig.18 The multiple comparison groups in FIG. 1 are stress distributions obtained when the total thickness of the copper material layer and the aluminum material layer is 300 nm. Fig.18 It can be clearly seen that as the thickness of the copper material layer and the aluminum material layer gradually approach, the internal stress of the interdigital electrode decreases, while the internal stress of the interdigital electrode of the full copper material (Full Cu) and the interdigital electrode of the full aluminum material (Full Al) reaches the maximum. It can be seen that the appropriate thickness combination of the copper material layer and the aluminum material layer can effectively reduce the stress amplitude. In addition, when the thickness of the copper material layer is 100nm, 150nm and 200nm, the stress at the interface of the copper material layer and the aluminum material layer is significantly improved (wherein the stress in the main area and the edge area of ​​the electrode is reduced), especially when the thickness ratio of the copper material layer to the aluminum material layer is 1:1, the stress value generated is the smallest.

[0133] In a further solution, an additional interface layer may be provided between the interdigitated electrode 200 and the piezoelectric layer 400 thereunder to compensate for stress deviation and reduce stress differences between adjacent film layers. The material of the interface layer used may include, for example, chromium (Cr), titanium (Ti), ruthenium (Ru) or aluminum nitride (AlN), silicon nitride (SiN), diamond-like carbon material (DLC), etc., and its thickness may be, for example, 5nm-15nm. Fig.19 This is the stress distribution diagram corresponding to the addition of the titanium material layer, such as Fig.19 As shown, when the thickness of the copper material layer is 100nm and 150nm, the stress at the interface between the copper material layer and the aluminum material layer is the smallest, especially when the thickness ratio of the copper material layer to the aluminum material layer is 1:2, the interface stress in the main area and the edge area of ​​the electrode can be greatly reduced.

[0134] Therefore, in the actual application of the ultrasonic transducer, the parameter ratio of each film layer in the interdigital electrode 200 can be adjusted according to the transverse mode suppression capability of the device, the heat dissipation and conductivity of the electrode, and the stress state of the electrode, so as to balance the various performances of the device. For example, in the case where the interdigital electrode has a copper material layer and an aluminum material layer stacked in the main area, and the total thickness of the electrode is 300nm, based on the conductivity and transverse mode suppression of the device, the thickness of the aluminum material layer can be selected to be approximately 60nm-120nm; and when the stress of the electrode is further considered, the thickness of the aluminum material layer can be further set to approximately 100nm. Of course, this is just an enumeration of one possible situation. In actual applications, it will be adjusted accordingly according to the material of the electrode, the thickness of the electrode and other parameters.

[0135] The transducer provided in the above embodiment also includes the use of different materials to form interdigital electrodes in a transverse composite manner. For example, in the first and second embodiments, the metal layer 200a in the main region 310 and the end block 200b in the edge region 320 are transversely bonded. The parameter ratio of each film layer in this embodiment can also be adjusted according to the transverse mode suppression capability of the device, the heat dissipation and conductivity of the electrode, and the stress state of the electrode, which will not be repeated here.

[0136] The surface acoustic wave transducer as described above can be specifically applied to surface acoustic wave devices, such as conventional surface acoustic wave filters, temperature-compensated surface acoustic wave filters, etc. The surface acoustic wave filter specifically includes a piezoelectric layer and a surface acoustic wave transducer formed on the piezoelectric layer. By using the surface acoustic wave transducer as described above, it can achieve higher power tolerance, thermal stability and conductivity, and also has the functions of suppressing transverse modes, reducing propagation losses, etc., effectively improving the overall performance of the device.

[0137] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. Also, although the present invention has been disclosed as above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

[0138] It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are only used to distinguish between various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between various components, elements, steps, etc. It should also be recognized that the singular forms "a" and "an" used herein and in the appended claims include plural references unless the context clearly indicates otherwise. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices.

Claims

1. A surface acoustic wave transducer, characterized in that: include: Two busbars and a plurality of interdigital electrodes are arranged opposite to each other, one end of each interdigital electrode is connected to one of the busbars, and the other end extends in a direction toward the other busbar, and the interdigital electrodes connected to different busbars are arranged crosswise in sequence; Among them, in the intersection area where the interdigitated electrodes are cross-arranged, the interdigitated electrodes have a main area and edge areas located on both sides of the main area, and the density of at least part of the material of the interdigitated electrodes in the edge area is higher than the material density in the main area.

2. The surface acoustic wave transducer according to claim 1, characterized in that: A metal layer is disposed in the main region of the interdigital electrodes, and an end block is disposed in the edge region of the interdigital electrodes. The density of the metal layer is lower than the density of the end block.

3. The surface acoustic wave transducer according to claim 2, characterized in that: The main region of the interdigital electrode is further provided with at least one non-metallic layer, the non-metallic layer and the metal layer are alternately stacked along the thickness direction, and the density of the non-metallic layer is not higher than the density of the end block.

4. The surface acoustic wave transducer according to claim 1, characterized in that: The interdigitated electrode comprises a main body layer and at least one embedded layer, wherein the main body layer extends from one end to the other end of the interdigitated electrode, the embedded layer is embedded into the main body layer in the main region, and the density of the embedded layer is less than that of the main body layer.

5. The surface acoustic wave transducer according to claim 4, characterized in that: The at least one embedded layer includes at least one metal layer and at least one non-metal layer, and the metal layer and the non-metal layer are alternately stacked along a thickness direction.

6. The surface acoustic wave transducer according to claim 1, characterized in that: A transverse mode suppression unit and a reflection unit are arranged in the edge region. The material density of the transverse mode suppression unit is higher than the material density in the main region. The reflection unit is arranged at intervals on a side of the transverse mode suppression unit away from the main region.

7. The surface acoustic wave transducer according to claim 6, characterized in that: A metal layer is disposed in the main region of the interdigital electrode, and a first end block is disposed in the edge region of the interdigital electrode. The first end block connects the end of the metal layer, and the density of the first end block is higher than that of the metal layer and is used to form the transverse mode suppression unit.

8. The surface acoustic wave transducer according to claim 7, characterized in that: A second end block is further disposed at an edge region of the interdigitated electrode, and the second end block is spaced apart and disposed at a side of the first end block away from the metal layer to form the reflection unit.

9. The surface acoustic wave transducer according to claim 6, characterized in that: The interdigital electrode comprises a main body layer and an embedded layer, wherein the main body layer extends from one end to the other end of the interdigital electrode, the embedded layer is stacked on the main body layer in the main region, and an end of the main body layer is protrudingly arranged to form the reflection unit.

10. The surface acoustic wave transducer according to claim 9, characterized in that: An end block is also provided in the edge region of the interdigital electrode, and the end block is connected to the end of the embedded layer.

11. A surface acoustic wave device, characterized in that: The invention comprises a surface acoustic wave transducer as claimed in any one of claims 1 to 10.

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