CN216122366U - Surface acoustic wave resonator and radio frequency filter - Google Patents
Surface acoustic wave resonator and radio frequency filter Download PDFInfo
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- CN216122366U CN216122366U CN202122353351.9U CN202122353351U CN216122366U CN 216122366 U CN216122366 U CN 216122366U CN 202122353351 U CN202122353351 U CN 202122353351U CN 216122366 U CN216122366 U CN 216122366U
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
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Abstract
The embodiment of the utility model provides a surface acoustic wave resonator and a radio frequency filter, wherein the surface acoustic wave resonator comprises a substrate; a piezoelectric layer on the substrate; the electrode layer is positioned on one side of the piezoelectric layer far away from the substrate; the electrode layer includes an interdigital transducer, and the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first bus bar includes at least one first sub-bus bar and at least one second sub-bus bar, the first sub-bus bar and the second sub-bus bar being connected; the second bus bar includes at least one third sub-bus bar and at least one fourth sub-bus bar. The acoustic surface wave resonator and the radio frequency filter provided by the embodiment of the utility model can effectively reduce the leakage of transverse energy, thereby improving the Q value of the resonator and further reducing the insertion loss of the radio frequency filter.
Description
Technical Field
The utility model relates to the field of communication, in particular to a surface acoustic wave resonator and a radio frequency filter.
Background
As communication technology advances from 2G to 5G, the number of communication bands increases (from 4 bands of 2G up to more than 50 bands of 5G). In order to improve the compatibility of the smart phone to different communication systems, the filter usage required by the 5G smart phone is remarkably increased, and the large-scale growth of the filter market is promoted. The radio frequency filter widely used in the wireless communication terminal at present is a surface acoustic wave filter, and is responsible for receiving and transmitting radio frequency signals of a channel and outputting signals with specific frequency in various input radio frequency signals. Meanwhile, with the continuous development of mobile communication technology and the modular development of radio frequency front end, the market demand for filters tends to be complicated, high-end and small.
Surface acoustic wave devices based on single crystal piezoelectric lithium tantalate substrates have been widely used in radio frequency filters, are limited by the Q value and high frequency temperature coefficient of single crystal piezoelectric materials, and have been difficult to meet the requirements of radio frequency front-end chips.
The surface acoustic wave resonator and the radio frequency filter which still adopt the traditional design can generate transverse energy leakage in practical application, and the higher the frequency is, the more serious the transverse energy leakage is, thereby causing the reduction of the Q value of the whole surface acoustic wave resonator.
SUMMERY OF THE UTILITY MODEL
The surface acoustic wave resonator and the radio frequency filter provided by the embodiment can effectively reduce the leakage of transverse energy, thereby improving the Q value of the resonator and further reducing the insertion loss of the radio frequency filter.
In a first aspect, an embodiment of the present invention provides a surface acoustic wave resonator, where the surface acoustic wave resonator includes:
a substrate;
a piezoelectric layer on the substrate;
an electrode layer located on a side of the piezoelectric layer away from the substrate;
the electrode layer includes an interdigital transducer, the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode fingers and the second dummy electrode fingers are arranged oppositely, first gaps are arranged between the first electrode fingers and the second dummy electrode fingers, the second electrode fingers and the first dummy electrode fingers are arranged oppositely, second gaps are arranged between the second electrode fingers and the first dummy electrode fingers, wherein the included angle between the arrangement direction of the first gaps and the first direction is larger than a set included angle, the included angle between the arrangement direction of the second gaps and the first direction is larger than a set included angle, the first direction is vertical to the length direction of the first electrode fingers in the direction parallel to the plane of the piezoelectric layer, wherein the lengths of any two first electrode fingers are equal in the length direction of the first electrode fingers, the lengths of any two first dummy electrode fingers are equal, and the lengths of any two second electrode fingers are equal, the lengths of any two second dummy electrode fingers are equal, and the set included angle is larger than 0 degree;
the first electrode finger and the second electrode finger both comprise a main body and a tip integrally connected with the main body, the tip of the first electrode finger is positioned on one side, away from the first bus bar, of the main body of the first electrode finger, and the tip of the second electrode finger is positioned on one side, away from the second bus bar, of the main body of the second electrode finger;
the first dummy electrode finger and the second dummy electrode finger both comprise a main body and a tip integrally connected with the main body, the tip of the first dummy electrode finger is positioned on the side, away from the first bus bar, of the main body of the first dummy electrode finger, and the tip of the second dummy electrode finger is positioned on the side, away from the second bus bar, of the main body of the second dummy electrode finger;
the first bus bar includes at least one first sub-bus bar and at least one second sub-bus bar, the first sub-bus bar and the second sub-bus bar being connected;
the second bus bar includes at least one third sub-bus bar and at least one fourth sub-bus bar, the third sub-bus bar being connected with the fourth sub-bus bar;
the first gap includes a first sub-gap and a second sub-gap, the second gap includes a third sub-gap and a fourth sub-gap, the first sub-gap and the third sub-gap are located between the first sub-bus bar and the third sub-bus bar, and the second sub-gap and the fourth sub-gap are located between the second sub-bus bar and the fourth sub-bus bar;
the arrangement direction of each first sub-gap is the same as that of each third sub-gap, the arrangement direction of each second sub-gap is the same as that of each fourth sub-gap, and the arrangement direction of the first sub-gaps is different from that of the second sub-gaps; each end head comprises a groove, the groove and the end head share a symmetry axis, and the depth of the groove is smaller than the length of the end head in the length direction of the first electrode finger;
in the first direction, the width of the tip is greater than the width of the body.
Optionally, in the first direction, the ratio of the width of the end head to the width of the main body is 1.2-1.8;
optionally, in the length direction of the first electrode finger, the ratio of the length of the tip to the depth of the groove includes 1.8-2.2.
Optionally, the range of the included angle between the arrangement direction of each first gap arrangement and the first direction includes 3 to 15 °, and the range of the included angle between the arrangement direction of each second gap arrangement and the first direction includes 3 to 15 °.
Optionally, the length of the first gap along the length direction of the first electrode finger comprises 0.18-0.3 μm;
the length of the second gap is 0.18-0.3 μm.
Optionally, the electrode layer further comprises a reflective gate structure;
the reflective gate structure includes a third bus bar, a fourth bus bar, and a plurality of reflective gates;
the third bus bar and the fourth bus bar are arranged in parallel;
the first end of the reflecting grid is connected with the third bus bar, and the second end of the reflecting grid is connected with the fourth bus bar;
in the first direction, the reflecting grating structures are positioned on two sides of the interdigital transducer;
the third bus bar is perpendicular to the reflective gate and the third bus bar is parallel to the first direction.
Optionally, the surface acoustic wave resonator provided in the embodiment of the present invention further includes an energy trap layer, where the energy trap layer is located between the substrate and the piezoelectric layer;
a first dielectric layer between the energy trap layer and the piezoelectric layer;
and the second dielectric layer is positioned on one side of the electrode layer, which is far away from the piezoelectric layer, and covers the electrode layer.
Optionally, the first bus bar includes at least two first sub-bus bars and at least two second sub-bus bars, and the first sub-bus bars and the second sub-bus bars are alternately connected;
the second bus bar includes at least two third sub-bus bars and at least two fourth sub-bus bars, the third sub-bus bars being alternately connected with the fourth sub-bus bars.
Optionally, the number of the first electrode fingers connected to the first sub-bus bar is not equal to the number of the first electrode fingers connected to the second sub-bus bar.
In a second aspect, the present invention further provides a radio frequency filter including the surface acoustic wave resonator provided in any of the embodiments of the present invention.
The embodiment of the utility model provides a surface acoustic wave resonator, wherein a first bus bar in an interdigital transducer comprises at least one first sub-bus bar and at least one second sub-bus bar, the second bus bar comprises at least one third sub-return bar and at least one fourth sub-bus bar, the first sub-bus bar is connected with the second sub-bus bar and is not parallel, the third sub-bus bar is connected with the fourth sub-bus bar and is not parallel, an included angle between the arrangement direction of a first gap arrangement between a first electrode finger and a second dummy electrode finger and the first direction is larger than a set included angle, an arrangement direction of a second gap arrangement between the second electrode finger and the first dummy electrode finger and the first direction are larger than the set included angle, and the first electrode finger, the second electrode finger, the first dummy electrode finger and the second dummy electrode finger all comprise a main body and a terminal integrally connected with the main body, wherein, each end includes a recess, and in the first direction, the width of end is greater than the width of main part, compares with current surface acoustic wave resonator, and the surface acoustic wave resonator that this embodiment provided can effectively reduce the leakage of transverse energy to improve the Q value of resonator, and then reduce radio frequency filter's insertion loss.
Drawings
Fig. 1 is a schematic structural diagram of a surface acoustic wave resonator according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an interdigital transducer provided in an embodiment of the present invention;
fig. 3 is a schematic structural diagram of another interdigital transducer provided in the present invention;
FIG. 4 is a schematic structural diagram of a conventional interdigital transducer;
fig. 5 is a schematic structural diagram of another interdigital transducer provided in the present invention;
fig. 6 is an actual view of admittance amplitudes of a surface acoustic wave resonator according to an embodiment of the present invention and an admittance amplitude of an existing surface acoustic wave resonator;
fig. 7 is an actual view of an admittance real part of a surface acoustic wave resonator according to an embodiment of the present invention and an admittance real part of an existing surface acoustic wave resonator;
fig. 8 is a graph comparing the smith curve of the saw resonator according to the embodiment of the present invention with the smith curve of the conventional saw resonator;
fig. 9 is an actual diagram of the Q values of the surface acoustic wave resonator provided by the embodiment of the present invention and the Q values of the surface acoustic wave resonator of the prior art;
fig. 10 is a schematic structural diagram of another interdigital transducer provided in accordance with an embodiment of the present invention;
fig. 11 is a schematic structural diagram of another interdigital transducer provided in accordance with an embodiment of the present invention;
fig. 12 is a schematic structural diagram of another interdigital transducer provided in the present invention.
Detailed Description
The embodiments of the present invention will be described in further detail with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad invention. It should be further noted that, for convenience of description, only some structures, not all structures, relating to the embodiments of the present invention are shown in the drawings.
Fig. 1 is a schematic structural diagram of a surface acoustic wave resonator according to an embodiment of the present invention, fig. 2 is a schematic structural diagram of an interdigital transducer according to an embodiment of the present invention, and fig. 3 is a schematic structural diagram of another interdigital transducer according to an embodiment of the present invention, referring to fig. 1, fig. 2, and fig. 3, the surface acoustic wave resonator includes: a substrate 110; a piezoelectric layer 120 on the substrate 110; an electrode layer 130, the electrode layer 130 being located on a side of the piezoelectric layer 120 away from the substrate 110; electrode layer 130 includes interdigital transducer 131, and interdigital transducer 131 includes: a first bus bar 10 and first electrode fingers 20 and first dummy electrode fingers 30 alternately arranged and connected to the first bus bar 10; a second bus bar 40 and second electrode fingers 50 and second dummy electrode fingers 60 alternately arranged and connected to the second bus bar 40; the first electrode fingers 20 and the second dummy electrode fingers 60 are oppositely arranged, first gaps 70 are arranged between the first electrode fingers 20 and the second dummy electrode fingers 60, the second electrode fingers 50 and the first dummy electrode fingers 30 are oppositely arranged, second gaps 80 are arranged between the second electrode fingers 50 and the first dummy electrode fingers 30, wherein the included angle between the arrangement direction of the first gaps 70 and the first direction x is larger than a set included angle, the included angle between the arrangement direction of the second gaps 80 and the first direction x is larger than the set included angle, in the direction parallel to the plane of the piezoelectric layer 120, the first direction x is vertical to the length direction of the first electrode fingers 20, in the length direction of the first electrode fingers 20, the lengths of any two first electrode fingers 20 are equal, the lengths of any two first dummy electrode fingers 30 are equal, the lengths of any two second electrode fingers 50 are equal, and the lengths of any two second dummy electrode fingers 60 are equal, setting the included angle to be more than 0 degree; each of the first electrode finger 20 and the second electrode finger 50 includes a main body 11 and a tip 12 integrally connected to the main body 11, the tip 12 of the first electrode finger 20 is located on a side of the main body 11 of the first electrode finger 20 away from the first bus bar 10, and the tip 12 of the second electrode finger 50 is located on a side of the main body 11 of the second electrode finger 50 away from the second bus bar 40; each of the first dummy electrode finger 30 and the second dummy electrode finger 60 includes a main body 11 and a tip 12 integrally connected to the main body 11, the tip 12 of the first dummy electrode finger 30 is located on a side of the main body 11 of the first dummy electrode finger 30 away from the first bus bar 10, and the tip 12 of the second dummy electrode finger 60 is located on a side of the main body 11 of the second dummy electrode finger 60 away from the second bus bar 40; the first bus bar 10 includes at least one first sub-bus bar 21 and at least one second sub-bus bar 22, the first sub-bus bar 21 and the second sub-bus bar 22 being connected; the second bus bar 40 includes at least one third sub-bus bar 41 and at least one fourth sub-bus bar 42, the third sub-bus bar 41 being connected with the fourth sub-bus bar 42; the first gap 70 includes a first sub-gap 71 and a second sub-gap 72, the second gap 80 includes a third sub-gap 81 and a fourth sub-gap 82, the first sub-gap 71 and the third sub-gap 81 are located between the first sub-bus bar 21 and the third sub-bus bar 41, and the second sub-gap 72 and the fourth sub-gap 82 are located between the second sub-bus bar 22 and the fourth sub-bus bar 42; wherein, the arrangement direction of each first sub-gap 71 is the same as the arrangement direction of each third sub-gap 81, the arrangement direction of each second sub-gap 72 is the same as the arrangement direction of each fourth sub-gap 82, and the arrangement direction of the first sub-gap 71 is different from the arrangement direction of the second sub-gap 72; each tip 12 comprises a groove 13, the groove 13 and the tip 12 share a symmetry axis, and the depth c of the groove 13 is smaller than the length d of the tip 12 along the length direction of the first electrode finger 20; in the first direction x, the width a of the tip 12 is greater than the width b of the body 11.
Specifically, the material of the substrate 110 may be high-resistivity silicon, which may be P-type high-resistivity silicon or N-type high-resistivity silicon, and the resistivity of the high-resistivity silicon is greater than 2000 Ω · cm, and preferably, the resistivity of the high-resistivity silicon is greater than 10000 Ω · cm. The piezoelectric layer 120 may be made of lithium tantalate or lithium niobate, wherein a cutting angle of lithium tantalate may be 30-50 °, a thickness of the piezoelectric layer 120 may be 300-1000 nm, and the electrode layer 130 is formed by depositing a metal film on the surface of the piezoelectric layer 120 by electron beam evaporation, plasma, magnetron sputtering, or the like, wherein the material of the deposited metal film may be titanium, chromium, copper, silver, aluminum, or the like, or a combination thereof. The range of the included angle between the arrangement direction of each first gap 70 and the first direction x may be 3 to 15 °, the range of the included angle between the arrangement direction of each second gap 80 and the first direction x may be 3 to 15 °, each of the first electrode finger 20, the second electrode finger 50, the first dummy electrode finger 30, and the second dummy electrode finger 60 includes a main body 11 and a tip 12, and the thickness of the tip 12 is the same as that of the main body 11. Fig. 2 exemplarily shows that the first bus bar 10 includes one first sub-bus bar 21 and one second sub-bus bar 22, and the second bus bar 40 includes one third sub-bus bar 41 and one fourth sub-bus bar 42. The arrangement direction of the first sub-gaps 71 is parallel to the extension direction of the first sub-bus bar 21, the arrangement direction of the second sub-gaps 72 is parallel to the extension direction of the second sub-bus bar 22, the arrangement direction of the third sub-gaps 81 is parallel to the extension direction of the third sub-bus bar 41, the arrangement direction of the fourth sub-gaps 82 is parallel to the extension direction of the fourth sub-bus bar 42, the first bus bar 10 is provided to include at least one first sub-bus bar 21 and at least one second sub-bus bar 22, the second bus bar 40 includes at least one third sub-bus bar 41 and at least one fourth sub-bus bar 42, the extension direction of the first sub-bus bar 21 is different from the extension direction of the second sub-bus bar 22, the extension direction of the third sub-bus bar 41 is different from the extension direction of the fourth sub-bus bar 42, leakage of lateral energy can be reduced, thereby increasing the Q value of the resonator, thereby reducing the insertion loss of the filter. The number of the first sub-bus bars 21 may be equal to or different from the number of the second sub-bus bars 22, and the number of the third sub-bus bars 41 may be equal to or different from the number of the fourth sub-bus bars 42. Fig. 3 schematically shows an enlarged view of the structure of the tip 12, and referring to fig. 3, the width a of the tip 12 is greater than the width b of the body 11 in the first direction x, and the depth c of the groove 13 is less than the length d of the tip 12 in the length direction of the first electrode finger.
Fig. 4 is a schematic structural diagram of a conventional interdigital transducer, referring to fig. 4, a first long electrode finger 111, a second long electrode finger 113, a first short electrode finger 112, and a second short electrode finger 114 in fig. 4 do not include a tip, fig. 5 is a schematic structural diagram of another interdigital transducer provided in an embodiment of the present invention, referring to fig. 5, the first electrode finger 20 in this embodiment is taken as an example for explanation, two cuboids are added to a side of the first electrode finger in fig. 4 away from the first bus bar, where the cuboid is partially shared with the first long electrode finger 111, so as to form the first electrode finger 20 provided in this embodiment, and similarly, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger in this embodiment are also formed in the same manner. In the length direction of the first electrode fingers, the length e of the first gap in fig. 3 is smaller than the length m of the first gap in fig. 4. The length of the first gap in the interdigital transducer provided by the present embodiment refers to the minimum distance between the oppositely disposed ends in the length direction of the first electrode finger, the length e of the first gap is as shown in fig. 3, and similarly, the length of the second gap has the same measurement method as the length of the first gap.
Fig. 6 is an actual view of the admittance amplitude of a surface acoustic wave resonator provided by the embodiment of the present invention and the admittance amplitude of an existing surface acoustic wave resonator, fig. 7 is an actual view of the admittance real part of a surface acoustic wave resonator provided by the embodiment of the present invention and the admittance real part of an existing surface acoustic wave resonator, referring to fig. 6 and 7, solid lines in fig. 6 and 7 both represent actual measurement curves of the surface acoustic wave resonator provided by the embodiment of the present invention, and dotted lines in fig. 6 and 7 both represent actual measurement curves of the existing surface acoustic wave resonator, as is apparent from fig. 6 and 7, a transverse mode ripple appearing in a relation curve of the admittance real part of the existing surface acoustic wave resonator and a frequency is generated, in an actual application, a plurality of transverse mode ripples are not suitable for generation of a radio frequency filter, and the surface acoustic wave resonator provided by the embodiment of the present invention can effectively suppress the transverse ripple, and further, the transverse energy leakage of the resonator can be effectively and obviously reduced. Fig. 8 is a graph comparing a smith curve of a surface acoustic wave resonator according to an embodiment of the present invention with a smith curve of a conventional surface acoustic wave resonator, in which a thick solid line in fig. 8 represents an actually measured curve of the surface acoustic wave resonator according to the embodiment, and a dotted line represents an actually measured curve of the conventional surface acoustic wave resonator, and it can be seen from fig. 8 that the performance of the surface acoustic wave resonator according to the embodiment is superior to that of the conventional surface acoustic wave resonator. Fig. 9 is a real-time graph of the Q value of the surface acoustic wave resonator according to the embodiment of the present invention and the Q value of the surface acoustic wave resonator according to the related art, the solid line in fig. 9 represents a real-time measurement curve of the surface acoustic wave resonator according to the embodiment, the broken line represents a real-time measurement curve of the related art surface acoustic wave resonator, and both the solid line and the broken line in fig. 9 are formed at a wavelength of 1.6 μm. The structure of the conventional surface acoustic wave resonator shown in fig. 6 to 9 is the structure shown in fig. 4.
The embodiment of the utility model provides a surface acoustic wave resonator, wherein a first bus bar in an interdigital transducer comprises at least one first sub-bus bar and at least one second sub-bus bar, the second bus bar comprises at least one third sub-return bar and at least one fourth sub-bus bar, the first sub-bus bar is connected with the second sub-bus bar and is not parallel, the third sub-bus bar is connected with the fourth sub-bus bar and is not parallel, an included angle between the arrangement direction of a first gap arrangement between a first electrode finger and a second dummy electrode finger and the first direction is larger than a set included angle, an arrangement direction of a second gap arrangement between the second electrode finger and the first dummy electrode finger and the first direction are larger than the set included angle, and the first electrode finger, the second electrode finger, the first dummy electrode finger and the second dummy electrode finger all comprise a main body and a terminal integrally connected with the main body, wherein, each end includes a recess, and in the first direction, the width of end is greater than the width of main part, compares with current surface acoustic wave resonator, and the surface acoustic wave resonator that this embodiment provided can effectively reduce the leakage of transverse energy to improve the Q value of resonator, and then reduce radio frequency filter's insertion loss.
Optionally, in the first direction, a ratio of the width of the tip to the width of the body includes 1.2 to 1.8.
Optionally, in the length direction of the first electrode finger, the ratio of the length of the tip to the depth of the groove includes 1.8-2.2.
Specifically, the width of the end is set to be 1.2-1.8 times of the width of the main body, the length of the end arranged in the length direction of the first electrode finger is set to be 0.3-0.7 times of the wavelength of the interdigital transducer, the ratio of the length of the end to the depth of the groove comprises 1.8-2.2, transverse energy leakage in surface acoustic waves can be further blocked by the end, clutter in the surface acoustic waves can be better inhibited, and the Q value of the surface acoustic wave resonator is further improved.
Optionally, the range of the included angle between the arrangement direction of each first gap arrangement and the first direction includes 3 to 15 °, and the range of the included angle between the arrangement direction of each second gap arrangement and the first direction includes 3 to 15 °.
Specifically, in the length direction of the first electrode fingers, the lengths of any two first electrode fingers are equal, the lengths of any two first dummy electrode fingers are equal, the lengths of any two second dummy electrode fingers are equal, then the extending direction of the first sub bus bars is the same as the arrangement direction of the first sub gaps, the extending direction of the second bus bars is the same as the arrangement direction of the second sub gaps, the extending direction of the third sub bus bars is the same as the arrangement direction of the third sub gaps, the extending direction of the fourth bus bars is the same as the arrangement direction of the fourth sub gaps, the range of the included angle between the arrangement direction of each first gap arrangement and the first direction is 3-15 degrees, the range of the included angle between the arrangement direction of each second gap arrangement and the first direction is 3-15 degrees, the acoustic surface wave resonator provided by the embodiment can better inhibit the noise wave in the acoustic surface wave, and further improves the Q value of the acoustic surface wave resonator.
Optionally, in the length direction of the first electrode finger, the length of the first gap includes 0.18 to 0.3 μm; the length of the second gap is 0.18 to 0.3 μm.
Specifically, the length of the first gap is 0.18-0.3 mu m, and the length of the second gap is 0.18-0.3 mu m, so that the end can further block transverse energy leakage in the surface acoustic wave, clutter in the surface acoustic wave is better suppressed, and the Q value of the surface acoustic wave resonator is further improved.
Alternatively, fig. 10 is a schematic structural diagram of another interdigital transducer provided in the embodiment of the present invention, and referring to fig. 10, the electrode layer further includes a reflective grid structure 132; the reflective fence structure 132 includes a third bus bar 90, a fourth bus bar 91, and a plurality of reflective fences 92; the third bus bar 90 and the fourth bus bar 91 are arranged in parallel; a first end of the reflection fence 92 is connected to the third bus bar 90, and a second end of the reflection fence 92 is connected to the fourth bus bar 91; in the first direction x, reflective grating structures 132 are located on both sides of the interdigital transducer 131; the third bus bar 90 is perpendicular to the reflective grating 92 and the third bus bar 90 is parallel to the first direction x.
Specifically, the reflection grating structure 132 may reflect energy of the surface acoustic wave, and concentrate the energy in the interdigital transducer 131, in the embodiment of the present invention, the reflection grating 92 is always disposed in parallel with the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger, so as to further ensure that the reflection grating structure 132 concentrates the reflected energy of the surface acoustic wave in the interdigital transducer 131, and further improve a Q value of the surface acoustic wave resonator, where the number of the reflection gratings may be twenty.
Optionally, with continued reference to fig. 1, the saw resonator further comprises an energy trap layer 140, the energy trap layer 140 being located between the substrate 110 and the piezoelectric layer 120; a first dielectric layer 150, the first dielectric layer 150 being located between the energy trap layer 140 and the piezoelectric layer 120; and the second medium layer 160, wherein the second medium layer 160 is positioned on one side of the electrode layer 130, which is far away from the piezoelectric layer 120, and covers the electrode layer 130.
Specifically, a layer of energy trap layer 140 is prepared on the substrate 110, the material of the energy trap layer 140 may be polysilicon, and the setting of the energy trap layer 140 may reduce the accumulation of charges, thereby further improving the Q value of the surface acoustic wave resonator. A layer of low-sound-velocity silicon dioxide is grown on the side, away from the substrate 110, of the energy trap layer 140 in a plasma enhanced chemical vapor deposition manner or a silicon thermal oxidation manner, so that the first dielectric layer 150 is formed, chemical mechanical planarization is adopted, the thickness value of the first dielectric layer 150 is finally controlled within the range of 300-800 nm, and the temperature drift coefficient of the first dielectric layer 150 can be further improved. The second dielectric layer 160 serves as a passivation layer and a frequency modulation layer of the saw surface wave resonator, the material of the second dielectric layer 160 may be silicon dioxide or silicon nitride, and the second dielectric layer 160 covers the electrode layer 130. The substrate 110, the energy trap layer 140 and the first dielectric layer 150 form a composite multilayer substrate, and the composite multilayer substrate in the embodiment of the utility model can enable the surface acoustic wave resonator and the radio frequency filter to realize the characteristics of low insertion loss, smooth pass band, high Q value, excellent low frequency temperature and the like.
Alternatively, fig. 11 is a schematic structural diagram of another interdigital transducer provided in an embodiment of the present invention, and referring to fig. 11, the first bus bar 10 includes at least two first sub-bus bars 21 and at least two second sub-bus bars 22, and the first sub-bus bars 21 and the second sub-bus bars 22 are alternately connected; the second bus bar 40 includes at least two third sub-bus bars 41 and at least two fourth sub-bus bars 42, and the third sub-bus bars 41 and the fourth sub-bus bars 42 are alternately connected.
Specifically, the surface acoustic wave resonator including two or more of the first sub bus bar 21, the second sub bus bar 22, the third sub bus bar 41, and the fourth sub bus bar 42 can also reduce leakage of lateral energy, thereby improving the Q value of the resonator and further reducing insertion loss of the filter.
Alternatively, fig. 12 is a schematic structural diagram of another interdigital transducer provided in an embodiment of the present invention, and referring to fig. 12, the number of first electrode fingers 20 connected to the first sub-bus bar 21 is not equal to the number of first electrode fingers 20 connected to the second sub-bus bar 22.
Specifically, referring to fig. 12, the number of the first electrode fingers 20 connected to the first sub-bus bar 21 is greater than the number of the first electrode fingers 20 connected to the second sub-bus bar 22, and the size of the included angle between the first sub-bus bar 21 and the first direction x may be different from the size of the included angle between the second sub-bus bar 22 and the first direction x. The number of the first sub-bus bars 21 connected with the first electrode fingers 20 is not equal to the number of the second sub-bus bars 22 connected with the first electrode fingers 20, so that the leakage of transverse energy can be reduced, the Q value of the resonator is improved, and the insertion loss of the filter is reduced.
The embodiment of the utility model also provides a radio frequency filter, which comprises the surface acoustic wave resonator provided by any embodiment of the utility model.
The radio frequency filter provided by the embodiment of the present invention and the surface acoustic wave resonator provided by any embodiment of the present invention have corresponding advantageous effects, and the technical details of the embodiment are not detailed, and the surface acoustic wave resonator provided by any embodiment of the present invention is detailed.
It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will appreciate that the embodiments of the present invention are not limited to the specific embodiments described herein, and that various obvious changes, adaptations, and substitutions are possible, without departing from the scope of the embodiments of the present invention. Therefore, although the embodiments of the present invention have been described in more detail through the above embodiments, the embodiments of the present invention are not limited to the above embodiments, and many other equivalent embodiments may be included without departing from the concept of the embodiments of the present invention, and the scope of the embodiments of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A surface acoustic wave resonator, comprising:
a substrate;
a piezoelectric layer on the substrate;
an electrode layer located on a side of the piezoelectric layer away from the substrate;
the electrode layer includes an interdigital transducer, the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode fingers and the second dummy electrode fingers are arranged oppositely, first gaps are arranged between the first electrode fingers and the second dummy electrode fingers, the second electrode fingers and the first dummy electrode fingers are arranged oppositely, second gaps are arranged between the second electrode fingers and the first dummy electrode fingers, wherein the included angle between the arrangement direction of the first gaps and the first direction is larger than a set included angle, the included angle between the arrangement direction of the second gaps and the first direction is larger than a set included angle, the first direction is vertical to the length direction of the first electrode fingers in the direction parallel to the plane of the piezoelectric layer, wherein the lengths of any two first electrode fingers are equal in the length direction of the first electrode fingers, the lengths of any two first dummy electrode fingers are equal, and the lengths of any two second electrode fingers are equal, the lengths of any two second dummy electrode fingers are equal, and the set included angle is larger than 0 degree;
the first electrode finger and the second electrode finger both comprise a main body and a tip integrally connected with the main body, the tip of the first electrode finger is positioned on one side, away from the first bus bar, of the main body of the first electrode finger, and the tip of the second electrode finger is positioned on one side, away from the second bus bar, of the main body of the second electrode finger;
the first dummy electrode finger and the second dummy electrode finger both comprise a main body and a tip integrally connected with the main body, the tip of the first dummy electrode finger is positioned on the side, away from the first bus bar, of the main body of the first dummy electrode finger, and the tip of the second dummy electrode finger is positioned on the side, away from the second bus bar, of the main body of the second dummy electrode finger;
the first bus bar includes at least one first sub-bus bar and at least one second sub-bus bar, the first sub-bus bar and the second sub-bus bar being connected;
the second bus bar includes at least one third sub-bus bar and at least one fourth sub-bus bar, the third sub-bus bar being connected with the fourth sub-bus bar;
the first gap includes a first sub-gap and a second sub-gap, the second gap includes a third sub-gap and a fourth sub-gap, the first sub-gap and the third sub-gap are located between the first sub-bus bar and the third sub-bus bar, and the second sub-gap and the fourth sub-gap are located between the second sub-bus bar and the fourth sub-bus bar;
the arrangement direction of each first sub-gap is the same as that of each third sub-gap, the arrangement direction of each second sub-gap is the same as that of each fourth sub-gap, and the arrangement direction of the first sub-gaps is different from that of the second sub-gaps; each end head comprises a groove, the groove and the end head share a symmetry axis, and the depth of the groove is smaller than the length of the end head in the length direction of the first electrode finger;
in the first direction, the width of the tip is greater than the width of the body.
2. The surface acoustic wave resonator according to claim 1, wherein a ratio of a width of the tip to a width of the body in the first direction includes 1.2 to 1.8.
3. The surface acoustic wave resonator according to claim 1, wherein a ratio of a length of the tip to a depth of the groove in a length direction of the first electrode finger includes 1.8 to 2.2.
4. The resonator according to claim 1, wherein the arrangement direction of each of the first gaps is included in an angle of 3 to 15 ° with respect to the first direction, and the arrangement direction of each of the second gaps is included in an angle of 3 to 15 ° with respect to the first direction.
5. The resonator of claim 1, wherein a length of the first gap comprises 0.18-0.3 μ ι η along a length direction of the first electrode finger;
the length of the second gap is 0.18-0.3 μm.
6. A surface acoustic wave resonator according to claim 1, wherein said electrode layer further includes a reflective gate structure;
the reflective gate structure includes a third bus bar, a fourth bus bar, and a plurality of reflective gates;
the third bus bar and the fourth bus bar are arranged in parallel;
the first end of the reflecting grid is connected with the third bus bar, and the second end of the reflecting grid is connected with the fourth bus bar;
in the first direction, the reflecting grating structures are positioned on two sides of the interdigital transducer;
the third bus bar is perpendicular to the reflective gate and the third bus bar is parallel to the first direction.
7. The surface acoustic wave resonator according to claim 1, further comprising an energy trap layer between the substrate and the piezoelectric layer;
a first dielectric layer between the energy trap layer and the piezoelectric layer;
and the second dielectric layer is positioned on one side of the electrode layer, which is far away from the piezoelectric layer, and covers the electrode layer.
8. The surface acoustic wave resonator according to claim 1, wherein the first bus bar includes at least two first sub-bus bars and at least two second sub-bus bars, the first sub-bus bars and the second sub-bus bars being alternately connected;
the second bus bar includes at least two third sub-bus bars and at least two fourth sub-bus bars, the third sub-bus bars being alternately connected with the fourth sub-bus bars.
9. The surface acoustic wave resonator according to claim 1 or 8, wherein the number of the first sub bus bar connecting the first electrode fingers is not equal to the number of the second sub bus bar connecting the first electrode fingers.
10. A radio frequency filter comprising the surface acoustic wave resonator according to any one of claims 1 to 9.
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| WO2023045733A1 (en) * | 2021-09-27 | 2023-03-30 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
| WO2023045732A1 (en) * | 2021-09-27 | 2023-03-30 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
| CN116566357A (en) * | 2023-04-28 | 2023-08-08 | 锐石创芯(重庆)科技有限公司 | Longitudinally coupled surface acoustic wave filter, hybrid filter and radio frequency front end module |
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| JP2020096226A (en) * | 2018-12-10 | 2020-06-18 | 太陽誘電株式会社 | Acoustic wave device, filter, and multiplexer |
| CN113098432A (en) * | 2021-04-08 | 2021-07-09 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
| CN113098430A (en) * | 2021-04-08 | 2021-07-09 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
| CN112953439A (en) * | 2021-04-08 | 2021-06-11 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
| CN113364421A (en) * | 2021-06-03 | 2021-09-07 | 成都频岢微电子有限公司 | Surface acoustic wave resonator, filter, and antenna duplexer |
| CN216122366U (en) * | 2021-09-27 | 2022-03-22 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023045733A1 (en) * | 2021-09-27 | 2023-03-30 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
| WO2023045732A1 (en) * | 2021-09-27 | 2023-03-30 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator and radio frequency filter |
| CN116566357A (en) * | 2023-04-28 | 2023-08-08 | 锐石创芯(重庆)科技有限公司 | Longitudinally coupled surface acoustic wave filter, hybrid filter and radio frequency front end module |
| CN116566357B (en) * | 2023-04-28 | 2024-04-05 | 锐石创芯(重庆)科技有限公司 | Longitudinally coupled surface acoustic wave filter, hybrid filter and radio frequency front end module |
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