Surface acoustic wave resonator and filter

Abstract

The application discloses a surface acoustic wave resonator and filter, and belongs to the technical field of semiconductors. The surface acoustic wave resonator comprises a piezoelectric layer, an interdigital transducer located on the piezoelectric layer, the interdigital transducer comprising a plurality of electrode fingers extending along a first direction and spaced along a second direction, the plurality of electrode fingers intersecting and overlapping in a region of acoustic wave propagation direction to form an overlapping area, the overlapping area comprising a main body area and two edge areas respectively corresponding to the opposite sides of the main body area along the first direction, the first direction being perpendicular to the second direction, and a plurality of first loads, the edge area of the electrode finger being provided with the first load, the first load having a first spacing between the edge away from the main body area and the same side edge of the edge area, and the first spacing corresponding to at least two first loads in the edge area being different. The application can suppress the transverse mode and improve the performance of the resonator.

Description

Technical Field

[0001] This application belongs to the field of semiconductor technology, and in particular relates to a surface acoustic wave resonator and filter. Background Technology

[0002] A surface acoustic wave (SAW) resonator is a high-frequency resonant device that uses sound waves propagating from the surface of a piezoelectric substrate. However, in addition to the main mode excitation, the resonator also excites a transverse mode, which can affect the resonator's performance. Utility Model Content

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a surface acoustic wave resonator and filter that can suppress transverse modes and improve the performance of the resonator.

[0004] In a first aspect, this application provides a surface acoustic wave resonator, comprising: piezoelectric layer; An interdigital transducer is located on the piezoelectric layer. The interdigital transducer includes a plurality of electrode fingers extending along a first direction and spaced apart along a second direction. The regions where the plurality of electrode fingers overlap in the direction of sound wave propagation constitute an overlapping region. The overlapping region includes a main body region and two edge regions located on opposite sides of the main body region along the first direction. The first direction and the second direction are perpendicular to each other. Multiple first loads are provided in the edge region of the electrode, and the first loads have a first distance between the edge of the first load away from the main body region and the edge of the edge region on the same side, and the first distances corresponding to at least two first loads in the edge region are different.

[0005] According to the surface acoustic wave resonator of this application, by setting a first load in the edge region of the electrode finger, the first load having a first gap between the edge of the main body region and the edge of the same side of the edge region, and the first gaps corresponding to at least two first loads in the edge region being different, the sound velocity of the sound wave in the first direction is changed, that is, the effect of acoustic impedance mismatch is achieved, so as to suppress the leakage of transverse sound wave energy, achieve the suppression of transverse mode, and improve the performance of the resonator.

[0006] According to one embodiment of this application, in each of the edge regions, each adjacent at least one first load constitutes a load group, the first spacing corresponding to each first load in the load group is the same, and the first spacing corresponding to each adjacent at least two load groups is different.

[0007] According to one embodiment of this application, in each of the said edge regions, the first spacing corresponding to at least two adjacent load groups decreases or increases along the direction of sound wave propagation; or, The first spacing corresponding to at least three adjacent load groups either decreases and then increases or increases and then decreases along the direction of sound wave propagation.

[0008] According to one embodiment of this application, the first load has a second spacing between its edge along the second direction and the edge of the corresponding electrode finger on the same side.

[0009] According to one embodiment of this application, the minimum distance of the first spacing and the minimum distance of the second spacing are respectively 0.005 wavelengths to 0.03 wavelengths; and / or, The length of the first load along the first direction is 0.4 wavelengths to 1 wavelength.

[0010] According to one embodiment of this application, the surface acoustic wave resonator further includes: Multiple second loads, which are located on top of the first load.

[0011] According to one embodiment of this application, the regions where the first loads on the plurality of electrode fingers overlap in the direction of sound wave propagation constitute a first overlapping region, and the second load is located in the first overlapping region of the corresponding first load.

[0012] According to one embodiment of this application, the edge of the second load has a third spacing with the edge of the corresponding first load on the same side.

[0013] According to one embodiment of this application, the minimum distance of the third spacing is 0.005 wavelengths to 0.03 wavelengths.

[0014] According to one embodiment of this application, the second load includes a plurality of sub-loads distributed along the first direction, with a fourth spacing between adjacent sub-loads.

[0015] According to one embodiment of this application, the minimum distance of the fourth spacing is 0.05 wavelengths to 1 wavelength.

[0016] According to one embodiment of this application, the electrode finger includes an end structure located in the edge region, the width of the end structure being greater than the body width of the electrode finger; The first load is located on the end structure of the corresponding electrode finger.

[0017] According to one embodiment of this application, the overlapping regions of the end structures of the plurality of electrodes in the direction of sound wave propagation constitute a second overlapping region, and the first load is located in the second overlapping region of the corresponding end structure.

[0018] According to one embodiment of this application, the surface acoustic wave resonator further includes: A reflective grating, located on the piezoelectric layer and on opposite sides of the interdigital transducer along the second direction, the reflective grating comprising a plurality of reflective strips extending along the first direction and spaced apart along the second direction; Multiple third loads are provided on the reflective strip, and the third loads are located in the extension area of ​​the edge region in the direction of sound wave propagation.

[0019] In a second aspect, this application provides a filter including a surface acoustic wave resonator as described in the first aspect above.

[0020] Thirdly, this application provides an electronic device including the filter as described in the second aspect above.

[0021] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects: By setting a first load in the edge region of the electrode finger, the first load having a first gap between the edge of the main body region and the edge of the same side of the edge region, and the first gaps corresponding to at least two first loads in the edge region being different, the sound wave velocity in the first direction is changed, that is, the effect of acoustic impedance mismatch is achieved, so as to suppress the leakage of transverse sound wave energy, suppress transverse modes, and improve the performance of the resonator.

[0022] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0023] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is one of the structural schematic diagrams of the surface acoustic wave resonator provided in the embodiments of this application; Figure 2 This is one of the cross-sectional views of the surface acoustic wave resonator provided in the embodiments of this application; Figure 3 This is one of the enlarged partial views of the surface acoustic wave resonator provided in the embodiments of this application; Figure 4 This is a second schematic diagram of the structure of the surface acoustic wave resonator provided in the embodiments of this application; Figure 5 This is the third schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 6 This is the fourth schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 7 This is the fifth schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 8 This is the sixth schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 9 This is one of the comparison diagrams showing the relationship between frequency and admittance of the surface acoustic wave resonator provided in the embodiments of this application and the related technologies; Figure 10 This is one of the comparison diagrams showing the relationship between frequency and conductance of the surface acoustic wave resonator provided in the embodiments of this application and the related technologies; Figure 11 This is the seventh schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 12 This is a second cross-sectional view of the surface acoustic wave resonator provided in the embodiments of this application; Figure 13 This is a second enlarged view of a surface acoustic wave resonator provided in the embodiments of this application; Figure 14 This is the second comparison diagram of the frequency and admittance relationship between related technologies and the surface acoustic wave resonators provided in the embodiments of this application; Figure 15 This is the second comparison diagram of the frequency and conductance relationship between the related technologies and the surface acoustic wave resonators provided in the embodiments of this application; Figure 16 This is the eighth schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 17 This is the third enlarged partial view of the surface acoustic wave resonator provided in the embodiments of this application; Figure 18 This is the ninth schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 19 This is the tenth schematic diagram of the surface acoustic wave resonator provided in the embodiments of this application; Figure 20 This is a schematic diagram of the filter structure provided in the embodiments of this application. Detailed Implementation

[0024] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0025] The surface acoustic wave resonator, filter, and electronic device provided in the embodiments of this application are described below with reference to the accompanying drawings.

[0026] Figure 1This is a schematic diagram of the structure of a surface acoustic wave resonator provided in an embodiment of this application.

[0027] like Figure 1 As shown, the surface acoustic wave resonator includes an overlap region 10, which includes a main body region 20 and two edge regions located on opposite sides of the main body region 20 along a first direction X. The two edge regions may include a first edge region 30a and a second edge region 30b, which are located on opposite sides of the main body region 20 along the first direction X.

[0028] In some embodiments, the surface acoustic wave resonator may further include busbar regions located on opposite sides of the overlap region 10 along the first direction X, and a gap region located between the overlap region 10 and the busbar regions, i.e., the busbar regions are located on the side of the edge region away from the main body region 20, and the gap region is located between the edge region and the busbar regions. The busbar regions may include a first busbar region and a second busbar region, the first busbar region being located on the side of the first edge region 30a away from the main body region 20, and the second busbar region being located on the side of the second edge region 30b away from the main body region 20. The gap regions may include a first gap region and a second gap region, the first gap region being located between the first edge region 30a and the first busbar region, and the second gap region being located between the second edge region 30b and the second busbar region.

[0029] like Figure 1 and Figure 2 As shown, the surface acoustic wave resonator includes a piezoelectric layer 1, an interdigital transducer 2, and multiple first loads 3.

[0030] In some embodiments, the surface acoustic wave resonator may further include a substrate, which may include a base plate and a support layer. The support layer is located on one side of the substrate in the thickness direction Z. The substrate may include a silicon substrate, etc. The support layer may include silicon oxide, such as silicon dioxide. Depending on the specific requirements, the substrate may also include other film layers, which are not specifically limited here.

[0031] The piezoelectric layer 1 can be located on one side of the substrate in the thickness direction Z. When the substrate includes a substrate and a support layer, the piezoelectric layer 1 is located on the side of the support layer away from the substrate. The piezoelectric layer 1 may include lithium tantalate (LiTaO3, abbreviated as LT), lithium niobate (LiNbO3), etc.

[0032] Interdigital transducers 2 are located on piezoelectric layer 1. In the case where the surface acoustic wave resonator also includes a substrate, the interdigital transducers 2 are located on the side of the piezoelectric layer 1 facing away from the substrate. The interdigital transducers 2 include a plurality of electrode fingers 21, each extending along a first direction X, and the plurality of electrode fingers 21 are spaced apart along a second direction Y. The thickness direction Z, the first direction X, and the second direction Y are perpendicular to each other. The overlapping regions of the plurality of electrode fingers 21 in the direction of acoustic wave propagation constitute an overlap region 10. The direction of acoustic wave propagation is perpendicular to the direction in which the electrode fingers 21 extend in the interdigital transducers 2.

[0033] In some embodiments, the interdigital transducer 2 further includes a first busbar 23 and a second busbar 24. Both the first busbar 23 and the second busbar 24 are located in the busbar region and extend along the second direction Y. The first busbar 23 is located in the first busbar region, and the second busbar 24 is located in the second busbar region.

[0034] The plurality of electrode fingers 21 includes first electrode fingers 21a and second electrode fingers 21b that are alternately and spaced apart along the second direction Y. The first electrode finger 21a extends along the first direction X and is connected to the first busbar 23. The first electrode finger 21a is located in the overlap region 10 and the first gap region, but not in the second gap region. The second electrode finger 21b extends along the first direction X and is connected to the second busbar 24. The second electrode finger 21b is located in the overlap region 10 and the second gap region, but not in the first gap region.

[0035] The number of first electrode fingers 21a and second electrode fingers 21b can be the same. The dimensions (including length and width) of the first electrode fingers 21a and second electrode fingers 21b can be the same. The materials of the first electrode fingers 21a and second electrode fingers 21b can include metals such as copper and aluminum. The first busbar 23 and second busbar 24 can serve as connecting lines to adjacent resonators or connecting lines to the package side. The materials of the first busbar 23 and second busbar 24 can include metals such as copper and aluminum.

[0036] A first load 3 is provided on the edge region of the electrode finger 21. The first load 3 is located on the electrode finger 21. The edge of the first load 3 away from the main body region 20 has a first distance between it and the edge of the same side of the edge region. The first distances corresponding to at least two first loads 3 in the edge region are different. The first load 3 can be provided in the edge region of each electrode finger 21 separately, or the first load 3 can be provided in the edge region of at least some of the electrode fingers 21.

[0037] The first edge region 30a of the electrode finger 21 may be provided with a first load 3, or the second edge region 30b of the electrode finger 21 may be provided with a first load 3, or the first edge region 30a and the second edge region 30b of the electrode finger 21 may each be provided with a first load 3.

[0038] Combination Figure 3As shown, the first edge region 30a and the second edge region 30b of the electrode finger 21 are respectively provided with a first load 3. The first load 3 in the first edge region 30a is away from the edge of the main body region 20. Figure 3 The upper edge of the first load 3) and the same side edge of the first edge region 30a ( Figure 3 The first spacing between the upper edges of the first edge region 30a and the second edge region 30b is gap1. The first load 3 in the second edge region 30b is away from the edge of the main body region 20. Figure 3 The lower edge of the first load 3) and the same side edge of the second edge region 30b ( Figure 3 The first gap between the lower edges of the second edge region 30b and the first load 3 on the same electrode can be the same or different. At least two first load 3s in the first edge region 30a have different gaps, and at least two first load 3s in the second edge region 30b have different gaps.

[0039] In this embodiment, a first load 3 is provided in the edge region of the electrode finger 21, and the first load 3 has a first gap between the edge away from the main body region 20 and the edge on the same side of the edge region. The first gaps corresponding to at least two first loads 3 in the edge region are different, so as to realize the change of the X-ray wave velocity along the first direction, that is, to achieve the effect of acoustic impedance mismatch, thereby suppressing the leakage of transverse acoustic wave energy, realizing the suppression of transverse mode, avoiding the transverse mode from deteriorating the insertion loss of the resonator passband and the performance of in-band ripple, thereby improving the resonator performance.

[0040] In some embodiments, in each edge region, each adjacent first load 3 constitutes a load group, and the first spacing corresponding to each first load 3 in the load group is the same, while the first spacing corresponding to each adjacent at least two load groups is different.

[0041] In the first edge region 30a, each adjacent first load constitutes a load group (i.e., a first load group), and the first spacing corresponding to each first load 3 in the first load group is the same. Each adjacent at least two first load groups can constitute a first unit, and the first spacing corresponding to each first load group in the first unit is different. The structures of different first units can be the same, that is, the changing trend of the first spacing corresponding to multiple first load groups in different first units can be the same.

[0042] In the second edge region 30b, each adjacent first load constitutes a load group (i.e., a second load group), and the first spacing corresponding to each first load 3 in the second load group is the same. Each adjacent at least two second load groups can constitute a second unit, and the first spacing corresponding to each second load group in the second unit is different. The structures of different second units can be the same, that is, the changing trend of the first spacing corresponding to multiple second load groups in different second units can be the same.

[0043] The number of first loads in the first load group and the second load group can be the same or different. The number of first load groups in the first unit and the number of second load groups in the second unit can be the same or different.

[0044] In some embodiments, in each edge region, the first spacing corresponding to at least two adjacent load groups decreases or increases along the direction of sound wave propagation. The direction of sound wave propagation is perpendicular to the direction in which the electrode fingers 21 in the interdigital transducer 2 extend.

[0045] The first spacing between the multiple first load groups in the first unit can decrease or increase along the direction of sound wave propagation, and the first spacing between the multiple second load groups in the second unit can decrease or increase along the direction of sound wave propagation. The changing trend of the first spacing between the multiple first load groups in the first unit and the changing trend of the first spacing between the multiple second load groups in the second unit can be the same or different.

[0046] like Figure 1 , Figure 3 and Figure 4 As shown, both the first load group and the second load group include one first load 3. The first unit includes two first load groups, that is, the first unit includes two first loads 3. The second unit includes two second load groups, that is, the second unit includes two first loads 3.

[0047] like Figure 1 and Figure 3 As shown, in the first unit, the first spacing between the two first loads 3 increases along the direction of sound wave propagation; that is, in the first edge region 30a, the first spacing gap1 between every two adjacent first loads 3 increases along the direction of sound wave propagation. In the second unit, the first spacing between the two first loads 3 decreases along the direction of sound wave propagation; that is, in the second edge region 30b, the first spacing gap1 between every two adjacent first loads 3 decreases along the direction of sound wave propagation.

[0048] like Figure 4 As shown, in the first unit, the first spacing between the two first loads 3 decreases along the direction of sound wave propagation; that is, in the first edge region 30a, the first spacing gap1 between each two adjacent first loads 3 decreases along the direction of sound wave propagation. In the second unit, the first spacing between the two first loads 3 decreases along the direction of sound wave propagation; that is, in the second edge region 30b, the first spacing gap1 between each two adjacent first loads 3 decreases along the direction of sound wave propagation.

[0049] like Figure 5 and Figure 6 As shown, both the first load group and the second load group include three first loads 3. The first unit includes two first load groups, and the second unit includes two second load groups.

[0050] like Figure 5 As shown, the first spacing between the three first loads 3 in the first load group is the same, and the first spacing between the two first load groups in the first unit increases along the direction of sound wave propagation. The first spacing between the three first loads 3 in the second load group is the same, and the first spacing between the two first load groups in the second unit decreases along the direction of sound wave propagation.

[0051] like Figure 6 As shown, the first spacing between the three first loads 3 in the first load group is the same, and the first spacing between the two first load groups in the first unit decreases along the direction of sound wave propagation. The first spacing between the three first loads 3 in the second load group is the same, and the first spacing between the two first load groups in the second unit decreases along the direction of sound wave propagation.

[0052] In some embodiments, the first spacing corresponding to each of at least three adjacent load groups decreases and then increases or increases and then decreases along the direction of sound wave propagation.

[0053] In the first unit, the first spacing corresponding to multiple first load groups can first decrease and then increase, or first increase and then decrease, along the direction of sound wave propagation. Similarly, in the second unit, the first spacing corresponding to multiple second load groups can first decrease and then increase, or first increase and then decrease, along the direction of sound wave propagation. The changing trends of the first spacing corresponding to multiple first load groups in the first unit and the changing trends of the first spacing corresponding to multiple second load groups in the second unit can be the same or different.

[0054] like Figure 7 and Figure 8 As shown, both the first load group and the second load group include one first load 3. The first unit includes six first load groups, that is, the first unit includes six first loads 3. The second unit includes six second load groups, that is, the second unit includes six first loads 3.

[0055] like Figure 7 As shown, in the first unit, the first spacing corresponding to the six first loads 3 firstly increases and then decreases along the direction of sound wave propagation; that is, in the first edge region 30a, the first spacing gap1 corresponding to every six adjacent first loads 3 firstly increases and then decreases along the direction of sound wave propagation. In the second unit, the first spacing corresponding to the six first loads 3 firstly increases and then decreases along the direction of sound wave propagation; that is, in the second edge region 30b, the first spacing gap1 corresponding to every six adjacent first loads 3 firstly increases and then decreases along the direction of sound wave propagation.

[0056] like Figure 8As shown, in the first unit, the first spacing corresponding to the six first loads 3 firstly decreases and then increases along the direction of sound wave propagation; that is, in the first edge region 30a, the first spacing gap1 corresponding to every six adjacent first loads 3 firstly decreases and then increases along the direction of sound wave propagation. In the second unit, the first spacing corresponding to the six first loads 3 firstly increases and then decreases along the direction of sound wave propagation; that is, in the second edge region 30b, the first spacing gap1 corresponding to every six adjacent first loads 3 firstly increases and then decreases along the direction of sound wave propagation.

[0057] In some embodiments, the minimum distance of the first gap 1 is 0.005 wavelengths to 0.03 wavelengths. Here, wavelength refers to the wavelength of surface acoustic waves propagating within the interdigital transducer 2.

[0058] In some embodiments, the length of the first load 3 along the first direction X is 0.4 wavelengths to 1 wavelength.

[0059] In some embodiments, the first load 3 has a second spacing between the edge along the second direction Y and the edge on the same side of the corresponding electrode finger 21.

[0060] Combination Figure 3 As shown, the first load 3 in the first edge region 30a is along the edge of the second direction Y (e.g.) Figure 3 The right edge of the first load 3) and the same side edge of the first edge region 30a (e.g., the ... Figure 3 The second spacing between the right edge of the first edge region 30a and the right edge of the second edge region 30b is gap2. The first load 3 in the second edge region 30b is located along the edge of the second direction Y (e.g. Figure 3 The right edge of the first load 3) and the same side edge of the second edge region 30b (e.g., the right edge of the first load 3) and the same side edge of the second edge region 30b) Figure 3 The second spacing between the right edges of the second edge region 30b is gap2. The second spacing gap2 corresponding to the two first loads 3 on the same electrode can be the same or different. The second spacing gap2 corresponding to the first loads 3 in the first edge region 30a can be the same or different, and the second spacing gap2 corresponding to the first loads 3 in the second edge region 30b can be the same or different.

[0061] In some embodiments, the minimum distance of the second spacing gap2 is 0.005 wavelengths to 0.03 wavelengths.

[0062] In some embodiments, the material of the first load 3 includes one or more combinations of metallic materials such as platinum, gold, copper, silver, titanium, aluminum, chromium, nickel, and lead, or silicon dioxide. It should be noted that the material of the first load 3 can be the same metallic material, different metallic materials, silicon dioxide, a combination of one metallic material and silicon dioxide, or a combination of different metallic materials and silicon dioxide.

[0063] Figure 9 For related technologies (without a first load) and the surface acoustic wave resonator in the embodiments of this application ( Figure 1 The diagram shows a comparison of the admittance curves of the surface acoustic wave resonator shown. Figure 10 For related technologies (without a first load) and the surface acoustic wave resonator in the embodiments of this application ( Figure 1 A comparison of the conductance curves of the surface acoustic wave resonator shown. Figure 9 and Figure 10 As can be seen, by setting the first load 3, the admittance and conductance curves of this embodiment are made smoother, thereby achieving a better transverse mode suppression effect, thereby improving the performance of the resonator, and consequently making the passband loss of the filter composed of the surface acoustic resonator in this embodiment smaller.

[0064] In some embodiments, such as Figure 11 and Figure 12 As shown, the surface acoustic wave resonator also includes: Multiple second loads 4, the second loads 4 are located on the first load 3.

[0065] The second load 4 can be set on each of the first loads 3, or the second load 4 can be set on at least some of the first loads 3.

[0066] In some embodiments, the material of the second load 4 includes one or more combinations of metallic materials such as platinum, gold, copper, silver, titanium, aluminum, chromium, nickel, and lead, or silicon dioxide. It should be noted that the material of the second load 4 can be the same metallic material, different metallic materials, silicon dioxide, a combination of one metallic material and silicon dioxide, or a combination of different metallic materials and silicon dioxide. The material of the second load 4 can be the same as or different from that of the first load 3.

[0067] In this embodiment, a second load 4 is provided on the first load 3, which can further change the sound wave velocity along the first direction X, thereby further suppressing the transverse mode.

[0068] In some embodiments, such as Figure 11 and Figure 13 As shown, the regions where the first loads 3 on the multiple electrode fingers 21 overlap in the direction of sound wave propagation constitute a first overlapping region 60, and the second load 4 is located in the first overlapping region 60 corresponding to the first load 3.

[0069] The overlapping areas of multiple first loads 3 in the first edge region 30a in the direction of sound wave propagation constitute a first overlapping region 60, and the overlapping areas of multiple first loads 3 in the second edge region 30b in the direction of sound wave propagation constitute a first overlapping region 60. A second load 4 is provided on the first overlapping region 60 of the first load 3.

[0070] In some embodiments, combined with Figure 13 As shown, the edge of the second load 4 has a third spacing with the edge of the corresponding first load 3 on the same side.

[0071] The second load 4 is located near the edge of the main body area 20. Figure 13 The lower edge of the second load 4) and the same side edge of the first load 3 ( Figure 13 The third spacing between the lower edge of the first load 3 and the second load 4 is gap3. The second load 4 is away from the edge of the main body area 20. Figure 13 The upper edge of the second load 4 and the same side edge of the first load 3 ( Figure 13 The third gap between the upper edges of the first load 3 and the second load 4 is gap3. The second load 4 is located along the edge of the second direction (…). Figure 13 The left / right edges of the second load 4 and the same side edges of the first load 3 ( Figure 13 The third gap between the left and right edges of the first load 3 is called gap3. The third gap3 corresponding to different second loads 4 can be the same or different.

[0072] In some embodiments, the minimum distance of the third gap 3 is 0.005 wavelengths to 0.03 wavelengths.

[0073] Figure 14 For related technologies (without a first load and a second load) and the surface acoustic wave resonator in the embodiments of this application ( Figure 11 The diagram shows a comparison of the admittance curves of the surface acoustic wave resonator shown. Figure 15 For related technologies (without a first load and a second load) and the surface acoustic wave resonator in the embodiments of this application ( Figure 11 A comparison of the conductance curves of the surface acoustic wave resonator shown. Figure 14 and Figure 15 As can be seen, by setting the first load 3 and the second load 4, the admittance and conductance curves of this embodiment are made smoother, thereby achieving a better transverse mode suppression effect, thereby improving the performance of the resonator, and consequently making the passband loss of the filter composed of the surface acoustic resonator in this embodiment of the application smaller.

[0074] In some embodiments, such as Figure 16 As shown, the second load 4 includes a plurality of sub-loads 41 distributed along the first direction X, with a fourth spacing between adjacent sub-loads 41.

[0075] Combination Figure 17As shown, the fourth spacing between adjacent sub-loads 41 is gap4. The fourth spacing gap4 corresponding to sub-loads in different second loads 4 can be the same or different. The number of sub-loads in the second load 4 can be set according to actual needs, and is not specifically limited here. The number of sub-loads 41 in different second loads 4 can be the same or different.

[0076] In some embodiments, the minimum distance of the fourth gap 4 is 0.05 wavelengths to 1 wavelength.

[0077] In some embodiments, such as Figure 18 As shown, electrode finger 21 includes an end structure 5 located in the edge region. The width of the end structure 5 is greater than the body width of electrode finger 21. The body width of electrode finger 21 refers to the width of electrode finger 21 at locations other than the end structure 5. A first load 3 is located on the end structure 5 of the corresponding electrode finger 21.

[0078] The first edge region 30a of the electrode finger 21 may have an end structure 5, or the second edge region 30b of the electrode finger 21 may have an end structure 5, or the first edge region 30a and the second edge region 30b of the electrode finger 21 may each have an end structure 5.

[0079] In this embodiment, an end structure 5 is provided in the edge region of the electrode finger 21, and a first load 3 is provided on the end structure 5, which can further change the acoustic wave velocity along the first direction X, thereby further suppressing the transverse mode.

[0080] In some embodiments, a fifth spacing exists between the edge of the end structure 5 away from the main body region 20 and the edge of the same side of the edge region. A fifth spacing exists between the edge of the end structure 5 in the first edge region 30a away from the main body region 20 and the edge of the same side of the first edge region 30a. A fifth spacing exists between the edge of the end structure 5 in the second edge region 30b away from the main body region 20 and the edge of the same side of the second edge region 30b. The fifth spacings corresponding to the two end structures 5 on the same electrode finger can be the same or different.

[0081] In some embodiments, the fifth spacings corresponding to at least two end structures 5 in the first edge region 30a are different, and the fifth spacings corresponding to at least two end structures 5 in the second edge region 30b are different.

[0082] In some embodiments, at least one adjacent end structure 5 in the first edge region 30a constitutes a first structure group. The fifth spacing corresponding to each end structure 5 in the first structure group is the same, and the fifth spacing corresponding to at least two adjacent first structure groups is different. The fifth spacing corresponding to at least two adjacent first structure groups can decrease or increase along the direction of sound wave propagation. The fifth spacing corresponding to at least three adjacent first structure groups can first decrease and then increase, or first increase and then decrease, along the direction of sound wave propagation.

[0083] In the second edge region 30b, each adjacent at least one end structure 5 constitutes a second structure group. The fifth spacing corresponding to each end structure 5 in the second structure group is the same, while the fifth spacing corresponding to each adjacent at least two second structure groups is different. The fifth spacing corresponding to each adjacent at least two second structure groups can decrease or increase along the direction of sound wave propagation. The fifth spacing corresponding to each adjacent at least three second structure groups can first decrease and then increase, or first increase and then decrease, along the direction of sound wave propagation.

[0084] In some embodiments, the length of the first load 3 along the first direction X is the same as the length of the end structure 5 along the first direction.

[0085] In some embodiments, such as Figure 19 As shown, the overlapping areas of the end structures 5 of the multiple electrode fingers 21 in the direction of sound wave propagation constitute a second overlapping area 70, and the first load 3 is located in the second overlapping area 70 of the corresponding end structure 21.

[0086] The overlapping areas of multiple end structures 5 in the first edge region 30a in the direction of sound wave propagation constitute a second overlapping region 70. The overlapping areas of multiple end structures 5 in the second edge region 30b in the direction of sound wave propagation constitute a second overlapping region 70. A first load 3 is provided on the second overlapping region 70 of the end structure 5.

[0087] In some embodiments, such as Figure 1 , Figures 3 to 8 As shown, the surface acoustic wave resonator also includes: The reflective grating 6 is located on the piezoelectric layer 1 and on opposite sides of the interdigital transducer 2 along the second direction Y. The reflective grating 6 includes a plurality of reflective strips 61 extending along the first direction X and spaced apart along the second direction Y. Multiple third loads 7 are provided on the reflective strip 61, and the third loads 7 are located in the edge region extending in the direction Y of sound wave propagation.

[0088] At least one end of the reflective strip 61 is provided with a third load 7. The third load 7 can be located in the extension region of the first edge region 30a in the direction of sound wave propagation, or it can be located in the extension region of the second edge region 30b in the direction of sound wave propagation. The position of the third load 7 on the reflective strip 61 can correspond to the position of the first load 3 on the electrode finger 21. The position variation pattern of the third load 7 on adjacent reflective strips 61 can be the same as the position variation pattern of the first load 3 on adjacent electrode fingers 21, which will not be described in detail here.

[0089] The material of the third load 7 may include one or more of the following: metals such as platinum, gold, copper, silver, titanium, aluminum, chromium, nickel, and lead, or silicon oxide. The materials of the third load 7 and the first load 3 may be the same or different.

[0090] In some embodiments, such as Figure 11 As shown, the surface acoustic wave resonator also includes: Multiple fourth loads 8 are located on multiple third loads 7 respectively.

[0091] The fourth load 8 may be located in the extension region of the first overlapping region 60 in the direction of sound wave propagation. The material of the fourth load 8 may include one or more combinations of metals such as platinum, gold, copper, silver, titanium, aluminum, chromium, nickel, and lead, or silicon oxide. The materials of the fourth load 8 may be the same as or different from those of the second load 4 and the third load 7.

[0092] In some embodiments, such as Figure 16 As shown, the fourth load 8 includes a plurality of sub-loads 81 distributed at intervals along the first direction X.

[0093] In some embodiments, such as Figure 18 As shown, the reflector strip 61 includes an end structure 9, and the end structure 9 of the reflector strip 61 is located in the extension region of the edge area in the direction of sound wave propagation. The width of the end structure 9 of the reflector strip 61 is greater than the width of the main body of the reflector strip 61. The third load 7 is located on the end structure 9 of the reflector strip 61.

[0094] In some embodiments, the end structure 9 of the reflective strip 61 is located in the extension region of the second overlapping region 70 in the direction of sound wave propagation.

[0095] The reflector grating 6 and the interdigital transducer 2 are the core structures of the surface acoustic wave resonator. The input interdigital transducer converts the electrical signal into a surface acoustic wave, which forms a standing wave resonance between the reflector gratings. The output interdigital transducer then converts the mechanical vibration back into an electrical signal.

[0096] It should be noted that the surface acoustic wave resonator in this embodiment can be applied to various acoustic devices, such as radio frequency filters, duplexers, delay lines, frequency discriminators, and modulators. For example, a filter based on a surface acoustic wave resonator can be used as an input / output filter for a receiver and transmitter, enabling simultaneous and effective wireless communication between multiple frequency bands and multiple devices.

[0097] According to the surface acoustic wave resonator provided in the embodiments of this application, by setting a first load 3 in the edge region of the electrode finger 21, the first load 3 has a first gap between the edge of the main body region 20 and the edge of the same side of the edge region, and the first gaps corresponding to at least two first loads 3 in the edge region are different, thereby realizing the change of sound wave velocity in the first direction X, that is, achieving the effect of acoustic impedance mismatch, so as to suppress the leakage of transverse sound wave energy, realize the suppression of transverse mode, and improve the performance of the resonator.

[0098] Accordingly, this application also provides a filter, including the surface acoustic wave resonator in the above embodiments, which will not be described in detail here.

[0099] In some embodiments, such as Figure 20 As shown, the filter includes multiple surface acoustic wave (SAW) resonators 100 connected in series and / or in parallel. The multiple SAW resonators 100 connected in series and parallel form a transmitting module TX, and the multiple SAW resonators 100 connected in series and parallel form a receiving module RX.

[0100] According to the filter provided in the embodiments of this application, by setting a first load in the edge region of the electrode finger, the first load having a first gap between the edge of the main body region and the edge of the same side of the edge region, and the first gaps corresponding to at least two first loads in the edge region being different, the sound wave velocity in the first direction is changed, that is, the effect of acoustic impedance mismatch is achieved, so as to suppress the leakage of transverse sound wave energy, achieve the suppression of transverse modes, improve the performance of the resonator, and thus improve the performance of the filter.

[0101] Accordingly, this application also provides an electronic device including the filter described in the above embodiments, which will not be described in detail here.

[0102] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more.

[0103] In the description of this application, "multiple" means two or more.

[0104] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0105] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A surface acoustic wave resonator, characterized in that, include: piezoelectric layer; An interdigital transducer is located on the piezoelectric layer. The interdigital transducer includes a plurality of electrode fingers extending along a first direction and spaced apart along a second direction. The regions where the plurality of electrode fingers overlap in the direction of sound wave propagation constitute an overlapping region. The overlapping region includes a main body region and two edge regions located on opposite sides of the main body region along the first direction. The first direction and the second direction are perpendicular to each other. Multiple first loads are provided in the edge region of the electrode, and the first loads have a first distance between the edge of the first load away from the main body region and the edge of the edge region on the same side, and the first distances corresponding to at least two first loads in the edge region are different.

2. The surface acoustic wave resonator according to claim 1, characterized in that, In each of the edge regions, each adjacent at least one of the first loads constitutes a load group, and the first spacing corresponding to each of the first loads in the load group is the same, while the first spacing corresponding to each adjacent at least two of the load groups is different.

3. The surface acoustic wave resonator according to claim 2, characterized in that, In each of the said edge regions, the first spacing corresponding to at least two adjacent load groups decreases or increases along the direction of sound wave propagation; or, The first spacing corresponding to at least three adjacent load groups either decreases and then increases or increases and then decreases along the direction of sound wave propagation.

4. The surface acoustic wave resonator according to claim 1, characterized in that, The first load has a second spacing between its edge along the second direction and the edge of the corresponding electrode finger on the same side.

5. The surface acoustic wave resonator according to claim 4, characterized in that, The minimum distance of the first spacing and the minimum distance of the second spacing are 0.005 wavelengths to 0.03 wavelengths, respectively; and / or, The length of the first load along the first direction is 0.4 wavelengths to 1 wavelength.

6. The surface acoustic wave resonator according to claim 1, characterized in that, The surface acoustic wave resonator also includes: Multiple second loads, which are located on top of the first load.

7. The surface acoustic wave resonator according to claim 6, characterized in that, The regions where the first loads on the plurality of electrode fingers overlap in the direction of sound wave propagation constitute a first overlapping region, and the second load is located in the first overlapping region of the corresponding first load.

8. The surface acoustic wave resonator according to claim 6, characterized in that, The edge of the second load has a third spacing with the edge of the corresponding first load on the same side.

9. The surface acoustic wave resonator according to claim 6, characterized in that, The second load includes a plurality of sub-loads distributed along the first direction, with a fourth spacing between adjacent sub-loads.

10. The surface acoustic wave resonator according to claim 1, characterized in that, The electrode finger includes an end structure located in the edge region, and the width of the end structure is greater than the width of the main body of the electrode finger; The first load is located on the end structure of the corresponding electrode finger.

11. The surface acoustic wave resonator according to claim 10, characterized in that, The overlapping areas of the end structures of the plurality of electrodes in the direction of sound wave propagation constitute a second overlapping area, and the first load is located in the second overlapping area of ​​the corresponding end structure.

12. The surface acoustic wave resonator according to any one of claims 1-11, characterized in that, The surface acoustic wave resonator also includes: A reflective grating, located on the piezoelectric layer and on opposite sides of the interdigital transducer along the second direction, the reflective grating comprising a plurality of reflective strips extending along the first direction and spaced apart along the second direction; Multiple third loads are provided on the reflective strip, and the third loads are located in the extension area of ​​the edge region in the direction of sound wave propagation.

13. A filter, characterized in that, Includes the surface acoustic wave resonator as described in any one of claims 1-12.

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