CN216929985U - Resonator and filter - Google Patents
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- CN216929985U CN216929985U CN202220402531.3U CN202220402531U CN216929985U CN 216929985 U CN216929985 U CN 216929985U CN 202220402531 U CN202220402531 U CN 202220402531U CN 216929985 U CN216929985 U CN 216929985U
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Abstract
The embodiment of the utility model discloses a resonator and a filter. The resonator includes: a substrate, a first surface of the substrate being provided with an acoustic reflection structure; the lower electrode is arranged on one side of the sound reflection structure far away from the substrate; the piezoelectric layer is arranged on one side of the lower electrode, which is far away from the substrate; wherein, one side of the piezoelectric layer adjacent to the lower electrode is provided with a first groove, and the vertical projection of the first groove on the substrate is overlapped or adjacent to the vertical projection part of the acoustic reflection structure on the substrate; and the upper electrode is arranged on one side of the piezoelectric layer, which is far away from the substrate. The embodiment of the utility model can avoid energy leakage to the substrate and improve the integral Q value of the resonator.
Description
Technical Field
The embodiment of the utility model relates to the technical field of semiconductors, in particular to a resonator and a filter.
Background
Resonators have been widely used in many fields. For example, in the field of wireless communications, resonators of Radio Frequency (RF) and microwave frequencies are used as filters to improve the reception and transmission of signals. With the demand for miniaturization and miniaturization of communication devices, resonators based on the piezoelectric effect have been proposed. In a resonator based on the piezoelectric effect, an acoustic resonance mode is generated in a piezoelectric material, in which an acoustic wave is converted into a radio wave.
Fig. 1 is a structural diagram of a resonator in the prior art, and referring to fig. 1, a conventional resonator based on the piezoelectric effect generally includes a substrate 101, a lower electrode 102, a piezoelectric layer 103 and an upper electrode 104, and energy leaks to the substrate 101 at an anchor point region (a region encircled by a dashed line in the figure) of the lower electrode 103 and the substrate 101, which affects the overall Q value of the resonator.
SUMMERY OF THE UTILITY MODEL
The utility model provides a resonator and a filter, which are used for avoiding energy leakage to a substrate and improving the integral Q value of the resonator.
In a first aspect, an embodiment of the present invention provides a resonator, including:
a substrate, a first surface of the substrate being provided with an acoustic reflection structure;
the lower electrode is arranged on one side of the acoustic reflection structure, which is far away from the substrate;
the piezoelectric layer is arranged on one side of the lower electrode, which is far away from the substrate; wherein, one side of the piezoelectric layer adjacent to the lower electrode is provided with a first groove, and the vertical projection of the first groove on the substrate is partially overlapped or adjacent to the vertical projection of the acoustic reflection structure on the substrate;
and the upper electrode is arranged on one side of the piezoelectric layer, which is far away from the substrate.
Optionally, at least a partial region of the first groove is located in a non-active region of the resonator.
Optionally, the first groove is located in the inactive area, and a perpendicular projection of a boundary of the first groove adjacent to the active area on the substrate coincides with a boundary of a perpendicular projection of the acoustic reflection structure on the substrate.
Optionally, at least one second groove is arranged on one side of the piezoelectric layer adjacent to the upper electrode; the vertical projection of the upper electrode on the piezoelectric layer is overlapped with the second groove, and the overlapped part of the upper electrode and the second groove is suspended on one side of the second groove far away from the substrate.
Optionally, a temperature compensation layer is filled in the first groove and/or the second groove.
Optionally, the first groove and/or the second groove are filled with a high-impedance material layer.
Optionally, the piezoelectric layer further includes a first release hole, and the first release hole is communicated with the first groove;
the upper electrode further comprises a second release hole, and the second release hole is communicated with the first release hole.
Optionally, the upper electrode further includes a third release hole, and the third release hole is communicated with the second groove.
Optionally, the upper electrode further includes a fourth release hole, and the fourth release hole is communicated with both the first groove and the second groove.
In a second aspect, an embodiment of the present invention further provides a filter, including at least one resonator according to any embodiment of the present invention.
According to the embodiment of the utility model, the first groove is arranged on one side of the piezoelectric layer, which is adjacent to the lower electrode, the vertical projection of the first groove on the substrate is partially overlapped or adjacent to the vertical projection of the acoustic reflection structure on the substrate, and the first groove can prevent the energy of the anchor point areas of the lower electrode and the substrate from leaking to the substrate, so that the integral Q value of the resonator is improved.
Drawings
FIG. 1 is a schematic diagram of a prior art resonator structure;
FIG. 2 is a schematic diagram of a resonator provided by an embodiment of the present invention;
FIG. 3 is a schematic diagram of yet another resonator provided by an embodiment of the present invention;
FIG. 4 is a schematic diagram of yet another resonator provided by an embodiment of the present invention;
FIG. 5 is a schematic diagram of yet another resonator provided by an embodiment of the present invention;
FIG. 6 is a schematic diagram of yet another resonator provided by an embodiment of the present invention;
fig. 7 is a schematic diagram of another resonator provided in an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting of the utility model. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
An embodiment of the present invention provides a resonator, fig. 2 is a schematic diagram of the resonator provided in the embodiment of the present invention, and referring to fig. 2, the resonator includes:
a substrate 10, a first surface of the substrate 10 being provided with an acoustic reflection structure 11;
a lower electrode 20 disposed on a side of the acoustic reflection structure 11 away from the substrate 10;
a piezoelectric layer 30 disposed on a side of the lower electrode 20 away from the substrate 10; wherein, one side of the piezoelectric layer 30 adjacent to the lower electrode 20 is provided with a first groove 31, and a vertical projection of the first groove 31 on the substrate 10 is partially overlapped or adjacent to a vertical projection of the acoustic reflection structure 11 on the substrate 10;
and an upper electrode 40 disposed on a side of the piezoelectric layer 30 remote from the substrate 10.
The acoustic reflection structure 11 may be a cavity or a bragg layer. When the acoustic reflection structure 11 is a bragg layer, a groove may be formed in the first surface of the substrate 10, and the bragg layer may be filled in the groove. When the acoustic reflection structure 11 is a cavity, the acoustic reflection structure 11 is disposed on the first surface, which may be formed by directly grooving the first surface of the substrate 10 as shown in fig. 1, or may be formed by disposing a support layer on the substrate 10 and forming a groove by the support layer, so as to form the acoustic reflection structure 11.
Furthermore, the overlap of the perpendicular projection of the first recess 31 on the substrate 10 and the perpendicular projection of the acoustic reflection structure 11 on the substrate 10 may include the following: the boundary of the first recess 31 adjacent to the perpendicular projection of the substrate 10 on the acoustic reflection structure 11 coincides with the boundary of the perpendicular projection of the acoustic reflection structure 11 on the substrate 10, or the perpendicular projection of the first recess 31 on the substrate 10 overlaps with a partial region of the perpendicular projection of the acoustic reflection structure 11 on the substrate 10.
The perpendicular projection of the first recess 31 on the substrate 10 is adjacent to the perpendicular projection of the acoustic reflection structure 11 on the substrate 10, i.e. the boundary of the perpendicular projection of the first recess 31 on the substrate 10 adjacent to the acoustic reflection structure 11 is adjacent to the boundary of the perpendicular projection of the acoustic reflection structure 11 on the substrate 10.
Referring to fig. 1, when the acoustic reflection structure 11 is a cavity, a groove may be formed in the substrate 10 through a photolithography process, the groove may be filled with a first sacrificial layer, and a material of the first sacrificial layer may include phosphosilicate glass (PSG), which illustratively includes 8% of phosphorus and 92% of silicon dioxide. The shape of the groove can be set according to needs, and exemplarily, the groove can be set as a groove with an inverted trapezoid cross section as shown in fig. 1.
After the first sacrificial layer is formed, the lower electrode 20 may be formed on the first surface of the substrate 10. The material of the lower electrode 20 may include molybdenum Mo or tungsten W. After the lower electrode 20 is formed, a second sacrificial layer may be formed on a surface of the lower electrode 20 away from the substrate 10, where the second sacrificial layer is disposed at a position corresponding to the first groove 31, and a shape of the second sacrificial layer is the same as a shape of the first groove 31. The material of the second sacrificial layer may also include phosphosilicate glass (PSG).
A piezoelectric layer 30 and an upper electrode 40 are then formed on the side of the second sacrificial layer remote from the substrate 10 and on the side of the lower electrode 20 remote from the substrate that is not covered by the second sacrificial layer. Due to the presence of the second sacrificial layer, at which the first recess 31 is formed correspondingly to the piezoelectric layer 30, and the first surface of the piezoelectric layer 30 away from the substrate 10 has a height change, the side of the piezoelectric layer 30 away from the substrate 10 can be planarized by chemical mechanical polishing, so as to form the piezoelectric layer 30 shown in fig. 2. Finally, the first sacrificial layer and the second sacrificial layer are removed, and the cavity type acoustic reflection structure 11 and the first groove 31 are formed.
In addition, the shape and size of the first groove 31 are not particularly limited in this embodiment, and the shape of an exemplary cross section perpendicular to the direction of the substrate 10 may be a trapezoid, a rectangle, or the like.
According to the embodiment of the utility model, the first groove 31 is arranged on one side of the piezoelectric layer 30 adjacent to the lower electrode 20, the vertical projection of the first groove 31 on the substrate 10 is partially overlapped or adjacent to the vertical projection of the acoustic reflection structure 11 on the substrate 10, and the first groove 31 can prevent energy of the anchor point areas of the lower electrode 103 and the substrate 10 from leaking to the substrate 10, so that the overall Q value of the resonator is improved.
Alternatively, referring to fig. 2, at least a partial region of the first groove 31 is located in the inactive region 110 of the resonator.
The active area 100 is an area where the acoustic reflection structure 11, the lower electrode 20, the piezoelectric layer 30, and the upper electrode 40 overlap, and the non-active area 110 is an area outside the active area. At least partial area of the first groove 31 is located in the inactive area 110 of the resonator, so that energy leakage from the anchor point areas of the lower electrode 20 and the substrate 10 to the substrate 10 can be better avoided, and the overall Q value of the resonator is improved.
Alternatively, referring to fig. 2, the first groove 31 is located in the non-active area 110, and a perpendicular projection of a boundary of the first groove 31 adjacent to the active area 100 on the substrate 10 coincides with a boundary of a perpendicular projection of the acoustic reflection structure 11 on the substrate 10. The leakage of the energy of the anchor point areas of the lower electrode 20 and the substrate 10 to the substrate 10 can be avoided, the thickness uniformity of the piezoelectric layer 30 of the active area 100 is better, and the performance of the resonator is improved.
Fig. 3 is a schematic diagram of another resonator provided by the embodiment of the present invention, and optionally, referring to fig. 3, at least one second groove 32 is provided on a side of the piezoelectric layer 30 adjacent to the upper electrode 40; wherein, the vertical projection of the upper electrode 40 on the piezoelectric layer 30 overlaps with the second groove 32, and the overlapping portion of the upper electrode 40 and the second groove 32 is suspended at one side of the second groove 32 away from the substrate 10.
Specifically, by forming the second groove 32 in the piezoelectric layer 30, a microstructure that reduces the propagation of mechanical waves in the horizontal direction is provided between the upper electrode 40 and the piezoelectric layer 30; such as by changing the shape of the second recess 32 to form at least one of a bridge structure, a wing structure, a convex structure, and a concave structure between the upper electrode 40 and the piezoelectric layer 30.
It should be noted that the second groove 32 may be formed on the side of the piezoelectric layer 30 away from the substrate 10 by photolithography and etching, and after the second groove 32 is formed, a third sacrificial layer may be formed in the second groove 32, then the upper electrode 40 is formed, and finally the third sacrificial layer in the second groove 32 is removed.
Fig. 4 is a schematic diagram of another resonator provided in an embodiment of the present invention, and optionally, referring to fig. 4, the first groove 31 and/or the second groove 32 is filled with a temperature compensation layer 50.
Specifically, the temperature compensation layer 50 may fill the first groove 31 and the second groove 32. The temperature compensation layer 50 can compensate the effect of temperature change on the resonator, and the temperature compensation layer 50 can be made of a material having a positive temperature coefficient, for example, the material of the temperature compensation layer 50 can include phosphorosilicate glass or silicon dioxide, and the temperature compensation layer 50 formed by using the above materials can better compensate the temperature of the resonator on one hand, and the manufacturing process of the above materials is easier to control on the other hand.
Fig. 5 is a schematic diagram of another resonator provided in an embodiment of the present invention, and optionally, referring to fig. 5, the first groove 31 and/or the second groove 32 are filled with a high-impedance material layer 60.
Specifically, the high-impedance material layer 60 is made of a high-impedance material, and the high-impedance material layer 60 is filled in the first groove 31 and the second groove 32, so that an acoustic impedance mismatch structure can be formed at one end of the lower electrode 20 and one end of the upper electrode 40, transverse waves are reflected, leakage is avoided, and the Q value is further improved. In addition, the high-resistance material layer 60 may be made of a material having a resistance greater than that of the piezoelectric layer 30, such as an unetchable borosilicate glass NEBSG, a carbon-doped oxide CDO, silicon carbide SiC, or silicon dioxide SiO 2.
In addition, referring to fig. 4 and 5, for the resonator with the temperature compensation layer 50 or the high-resistance material layer 60 filled in the first groove 31, the specific manufacturing process may be as follows: after the lower electrode 20 is formed, a temperature compensation layer 50 or a high-resistance material layer 60 may be formed on a surface of the lower electrode 20 away from the substrate 10, the temperature compensation layer 50 or the high-resistance material layer 60 is disposed at a position corresponding to the first groove 31, and a shape of the temperature compensation layer 50 or the high-resistance material layer 60 is the same as a shape of the first groove 31. The piezoelectric layer 30 and the upper electrode 40 are then formed on the side of the temperature compensation layer 50 or the high-resistance material layer 60 away from the substrate 10. And finally, removing the first sacrificial layer.
For the resonator with the temperature compensation layer 50 or the high-impedance material layer 60 filled in the second groove 32, the specific manufacturing process may be: after the piezoelectric layer 30 is formed, a temperature compensation layer 50 or a high-impedance material layer 60 may be formed on a surface of the piezoelectric layer 30 away from the substrate 10, the temperature compensation layer 50 or the high-impedance material layer 60 is disposed at a position corresponding to the second groove 32, and a shape of the temperature compensation layer 50 or the high-impedance material layer 60 is the same as a shape of the second groove 32. The upper electrode 40 is then formed on the side of the temperature compensation layer 50 or the high-resistance material layer 60 away from the substrate 10. And finally, removing the first sacrificial layer.
Fig. 6 is a schematic view of another resonator provided by the embodiment of the present invention, and optionally, referring to fig. 6, the piezoelectric layer 30 further includes a first release hole 33, and the first release hole 33 is communicated with the first groove 31; the upper electrode 40 further includes a second release hole 41, and the second release hole 41 communicates with the first release hole 33.
Specifically, the first release hole 33 and the second release hole 41 are used to remove the second sacrificial layer in the first groove 31. Specifically, the second sacrificial layer may be removed by etching using an etching solution by injecting the etching solution into the first release hole 33 and the second release hole 41.
Optionally, the upper electrode 40 further includes a third release hole 42, and the third release hole 42 is in communication with the second groove 32.
Specifically, the third release hole 42 is used to remove the third sacrificial layer in the second groove 32. Specifically, the third sacrificial layer may be removed by etching with an etching solution by injecting the etching solution into the third release hole 42.
Fig. 7 is a schematic diagram of another resonator provided by the embodiment of the present invention, and optionally, referring to fig. 7, the upper electrode 40 further includes a fourth release hole 43, and the fourth release hole 43 is communicated with both the first groove 31 and the second groove 32.
Specifically, the fourth release hole 43 is used to remove the second sacrificial layer in the first groove 31 and the third sacrificial layer in the second groove 32. The third sacrificial layer and the second sacrificial layer may be removed by etching with an etching liquid by injecting the etching liquid into the fourth release hole 43.
The embodiment of the utility model also provides a filter which comprises at least one resonator in any embodiment of the utility model.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements, substitutions and combinations, as will now become apparent to those skilled in the art, without departing from the scope of the utility model. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A resonator, comprising:
a substrate, a first surface of the substrate being provided with an acoustic reflection structure;
the lower electrode is arranged on one side of the acoustic reflection structure, which is far away from the substrate;
the piezoelectric layer is arranged on one side of the lower electrode, which is far away from the substrate; wherein, one side of the piezoelectric layer adjacent to the lower electrode is provided with a first groove, and the vertical projection of the first groove on the substrate is partially overlapped or adjacent to the vertical projection of the acoustic reflection structure on the substrate;
and the upper electrode is arranged on one side of the piezoelectric layer, which is far away from the substrate.
2. The resonator of claim 1, wherein:
at least partial area of the first groove is located in the non-active area of the resonator.
3. The resonator of claim 2, wherein:
the first groove is located in the non-active area, and the vertical projection of the boundary of the first groove adjacent to the active area on the substrate is coincident with the vertical projection of the acoustic reflection structure on the substrate.
4. The resonator of claim 1, wherein:
at least one second groove is formed in one side, adjacent to the upper electrode, of the piezoelectric layer; the vertical projection of the upper electrode on the piezoelectric layer is overlapped with the second groove, and the overlapped part of the upper electrode and the second groove is suspended on one side of the second groove far away from the substrate.
5. The resonator of claim 4, wherein:
and a temperature compensation layer is filled in the first groove and/or the second groove.
6. The resonator of claim 4, wherein:
and the first groove and/or the second groove are/is filled with a high-impedance material layer.
7. The resonator of claim 1, wherein:
the piezoelectric layer further comprises a first release hole, and the first release hole is communicated with the first groove;
the upper electrode further comprises a second release hole, and the second release hole is communicated with the first release hole.
8. The resonator of claim 4, wherein:
the upper electrode further comprises a third release hole, and the third release hole is communicated with the second groove.
9. The resonator of claim 4, wherein:
the upper electrode further comprises a fourth release hole, and the fourth release hole is communicated with the first groove and the second groove.
10. A filter, characterized in that it comprises at least one resonator according to any of claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220402531.3U CN216929985U (en) | 2022-02-25 | 2022-02-25 | Resonator and filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220402531.3U CN216929985U (en) | 2022-02-25 | 2022-02-25 | Resonator and filter |
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| Publication Number | Publication Date |
|---|---|
| CN216929985U true CN216929985U (en) | 2022-07-08 |
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| CN202220402531.3U Active CN216929985U (en) | 2022-02-25 | 2022-02-25 | Resonator and filter |
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| CN (1) | CN216929985U (en) |
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- 2022-02-25 CN CN202220402531.3U patent/CN216929985U/en active Active
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