Elastic wave resonance device, forming method thereof and filter

Abstract

The invention discloses an elastic wave resonance device, a forming method thereof and a filter. The resonance device comprises a substrate; the Bragg reflection layer is located on the substrate, the Bragg reflection layer comprises at least two first sub-layers and at least two second sub-layers, the first sub-layers and the second sub-layers are alternately stacked and arranged, and the Bragg reflection layer comprises crystal defects; the piezoelectric layer is located on the Bragg reflection layer, the piezoelectric layer comprises a first side and a second side which are opposite to each other, and the Bragg reflection layer and the substrate are located on the first side; and the electrode structure is positioned on at least one side of the piezoelectric layer. The crystal defects in the Bragg reflection layer can form a charge trap, and a conductive plane can be prevented from being formed on the surface of the substrate, so that the generated parasitic coupling phenomenon is effectively inhibited, the electric loss is reduced, and the Q value of the resonance device or the electromechanical coupling coefficient (Kt) of the resonance device is improved. In addition, the Bragg reflection layer can effectively reduce sound wave leakage.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an elastic wave resonance device and a forming method thereof, and a filter. Background Art

[0002] The RF front-end chips of wireless communication devices include power amplifiers, antenna switches, RF filters, multiplexers, and low-noise amplifiers, etc. Among them, RF filters include surface acoustic wave (SAW) filters, bulk acoustic wave (BAW) filters, micro-electro-mechanical system (MEMS) filters, integrated passive devices (IPD) filters, etc.

[0003] However, there are still many problems with elastic wave resonance devices. Summary of the invention

[0004] The problem solved by the present invention is to provide an elastic wave resonance device and a forming method thereof, and a filter, so as to improve the Q value of the resonance device or the electromechanical coupling coefficient (Kt) of the resonance device.

[0005] To solve the above problems, the technical solution of the present invention provides an elastic wave resonance device, comprising: a substrate; a Bragg reflection layer, located on the substrate, the Bragg reflection layer comprising at least 2 first sub-layers and at least 2 second sub-layers, the first sub-layers and the second sub-layers are alternately stacked and arranged, and the Bragg reflection layer comprises crystal defects; a piezoelectric layer, located on the Bragg reflection layer, the piezoelectric layer comprising a first side and a second side opposite to each other, the Bragg reflection layer and the substrate are located on the first side; an electrode structure, located on at least one side of the piezoelectric layer.

[0006] Optionally, the material of the first sublayer is silicon dioxide; the material of the second sublayer is tungsten or aluminum nitride.

[0007] Optionally, the crystal defect is located at an interface between the first sub-layer and the second sub-layer.

[0008] Optionally, the interface is close to the substrate.

[0009] Optionally, the crystal defect is located in the first sub-layer or in the second sub-layer.

[0010] Optionally, the first sublayer or the second sublayer is close to the substrate.

[0011] Optionally, the crystal defects include: one or more of: point defects, line defects, surface defects and lattice mismatch.

[0012] Optionally, the point defect includes: a vacancy defect or an impurity defect.

[0013] Optionally, the vacancy defect includes: a Frankel vacancy or a Schottky vacancy.

[0014] Optionally, the impurity defects include: interstitial impurities or substitutional impurities.

[0015] Optionally, the line defect includes: a dislocation defect.

[0016] Optionally, the dislocation defect includes: edge dislocation or screw dislocation.

[0017] Optionally, the surface defect includes: a translation interface, a twin interface or a grain boundary.

[0018] Optionally, the translation interface includes: surface state defects.

[0019] Optionally, the surface state defects include: reconstructed atoms or relaxed surfaces.

[0020] Optionally, there is a lattice mismatch between materials of the first sub-layer and the second sub-layer.

[0021] Optionally, a lattice mismatch between the first sub-layer and the second sub-layer is greater than 5%.

[0022] Optionally, the electrode structure is located on the second side of the piezoelectric layer, and the electrode structure includes: a first bus and a second bus arranged in parallel along a first direction; a plurality of first electrode strips connected to the first bus, and the plurality of first electrode strips are arranged in parallel along a second direction, and the first direction is perpendicular to the second direction; a plurality of second electrode strips connected to the second bus, and the plurality of second electrode strips are arranged in parallel along the second direction, the first electrode strips and the second electrode strips are staggered, and the first electrode strips and the second electrode strips have an overlapping area along the second direction.

[0023] Optionally, it also includes: a protective layer, located on the piezoelectric layer and covering the electrode structure.

[0024] Optionally, it also includes: a temperature compensation layer, which is located on the piezoelectric layer and covers the electrode structure.

[0025] Optionally, the electrode structure includes: a first electrode layer located on the Bragg reflection layer, the first electrode layer being located on a first side of the piezoelectric layer; a second electrode layer being located on a second side of the piezoelectric layer, and projections of the first electrode layer and the second electrode layer toward the substrate have an overlapping area.

[0026] Correspondingly, the technical solution of the present invention also provides a method for forming an elastic wave resonance device, comprising: providing a substrate; forming a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite to each other, the substrate being located on the first side; forming a Bragg reflection layer, located between the substrate and the piezoelectric layer, the Bragg reflection layer comprising at least 2 first sub-layers and at least 2 second sub-layers, the first sub-layers and the second sub-layers being alternately stacked and arranged, and the Bragg reflection layer comprising crystal defects; forming an electrode structure, located on at least one side of the piezoelectric layer.

[0027] Optionally, forming the Bragg emission layer includes: forming the crystal defect at an interface between the first sub-layer and the second sub-layer.

[0028] Optionally, the interface is close to the substrate.

[0029] Optionally, forming the Bragg emission layer includes: forming the crystal defect in the first sub-layer or in the second sub-layer.

[0030] Optionally, the first sublayer or the second sublayer is close to the substrate.

[0031] Optionally, the crystal defects include: one or more of: point defects, line defects, surface defects and lattice mismatch.

[0032] Optionally, there is a lattice mismatch between materials of the first sub-layer and the second sub-layer.

[0033] Optionally, a lattice mismatch between the first sub-layer and the second sub-layer is greater than 5%.

[0034] Optionally, the Bragg reflection layer is formed on one side of the substrate, and the piezoelectric layer and the Bragg reflection layer are bonded.

[0035] Optionally, the Bragg reflection layer is formed on the first side of the piezoelectric layer, and the Bragg reflection layer and the substrate are bonded.

[0036] Optionally, the electrode structure is located on the second side of the piezoelectric layer, and forming the electrode structure includes: forming a first bus and a second bus arranged in parallel along a first direction; forming a plurality of first electrode strips connected to the first bus, and the plurality of first electrode strips are arranged in parallel along a second direction, and the first direction is perpendicular to the second direction; forming a plurality of second electrode strips connected to the second bus, and the plurality of second electrode strips are arranged in parallel along the second direction, the first electrode strips and the second electrode strips are staggered, and the first electrode strips and the second electrode strips have an overlapping area along the second direction.

[0037] Optionally, the method further includes: forming a protective layer located on the second side of the piezoelectric layer and covering the electrode structure.

[0038] Optionally, the method further includes: forming a temperature compensation layer, which is located on the second side of the piezoelectric layer and covers the electrode structure.

[0039] Optionally, forming the electrode structure includes: forming a first electrode layer located on a first side of the piezoelectric layer, the Bragg reflection layer being located between the substrate and the first electrode layer; forming a second electrode layer located on a second side of the piezoelectric layer, the projections of the first electrode layer and the second electrode layer toward the substrate having an overlapping area.

[0040] Correspondingly, the technical solution of the present invention further provides a filter, comprising: an elastic wave resonance device as described in any one of the technical solutions above.

[0041] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0042] In the elastic wave resonance device of the technical solution of the present invention, the crystal defects in the Bragg reflection layer can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate, thereby effectively suppressing the parasitic coupling phenomenon generated and reducing electrical losses, thereby improving the Q value of the resonance device or the electromechanical coupling coefficient (Kt) of the resonance device. In addition, the use of the Bragg reflection layer can effectively reduce sound wave leakage, reduce the acoustic energy loss of the elastic wave resonance device, and improve the Q value of the resonance device.

[0043] Furthermore, the crystal defect is located at the interface between the first sublayer and the second sublayer; the interface is close to the substrate, which can make the crystal defect stay away from the piezoelectric layer, further suppress the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate, reduce electrical loss, and thus improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0044] Furthermore, the crystal defect is located in the first sublayer or the second sublayer; the first sublayer or the second sublayer is close to the substrate, which can make the crystal defect stay away from the piezoelectric layer, further suppress the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate, reduce electrical loss, and thus improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0045] In the method for forming an elastic wave resonant device of the technical solution of the present invention, the crystal defects in the Bragg reflective layer can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate, thereby effectively suppressing the parasitic coupling phenomenon generated and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device. In addition, the use of the Bragg reflective layer can effectively reduce acoustic wave leakage, reduce the acoustic energy loss of the elastic wave resonant device, and improve the Q value of the resonant device.

[0046] Furthermore, forming the Bragg emission layer includes: forming the crystal defect at the interface between the first sublayer and the second sublayer; the interface is close to the substrate, which can make the crystal defect stay away from the piezoelectric layer, further suppress the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate, and reduce electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0047] Furthermore, forming the Bragg emission layer includes: forming the crystal defect in the first sublayer or the second sublayer; the first sublayer or the second sublayer is close to the substrate, so that the crystal defect can be kept away from the piezoelectric layer, further suppressing the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate, reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the structure of a surface acoustic wave resonance device;

[0049] Figures 2 to 6 is a structural schematic diagram of each step of a method for forming an elastic wave resonance device in an embodiment of the present invention;

[0050] Figure 7 Schematic diagram of a defect of a Frankel vacancy in an embodiment of the present invention;

[0051] Figure 8 is a schematic diagram of a defect of a Schottky vacancy in another embodiment of the present invention;

[0052] Fig. 9 is a schematic diagram of defects of interstitial impurities in another embodiment of the present invention;

[0053] Fig.10 is a schematic diagram of defects of substitutional impurities in another embodiment of the present invention;

[0054] Fig.11 is a schematic diagram of an edge dislocation defect in another embodiment of the present invention;

[0055] Fig.12 is a schematic diagram of a screw dislocation defect in another embodiment of the present invention;

[0056] Fig.13 is a schematic diagram of defects in reconstructing atoms in another embodiment of the present invention;

[0057] Fig.14 is a schematic diagram of defects on a relaxed surface in another embodiment of the present invention;

[0058] Fig.15 is a schematic diagram of a lattice mismatch defect in another embodiment of the present invention;

[0059] Figures 16 to 20 is a schematic structural diagram of each step of a method for forming an elastic wave resonance device in another embodiment of the present invention;

[0060] Fig.21 It is a schematic structural diagram of an elastic wave resonance device in another embodiment of the present invention. DETAILED DESCRIPTION

[0061] As described in the background art, elastic wave resonance devices still have many problems, which will be described in detail below with reference to the accompanying drawings.

[0062] Figure 1 It is a structural schematic diagram of a surface acoustic wave resonance device.

[0063] Please refer to Figure 1 A surface acoustic wave resonance device includes: a substrate 100; an intermediate layer 101, located on the substrate 100; a piezoelectric layer 102, located on the intermediate layer 101, the piezoelectric layer 102 includes a first side 102a and a second side 102b opposite to each other, the intermediate layer 101 and the substrate 100 are located on the first side 102a of the piezoelectric layer 102; an electrode structure 103, located on the second side 102b of the piezoelectric layer 101.

[0064] In this embodiment, there is a parasitic surface conductance (PSC) effect at the interface between the intermediate layer 101 and the substrate 100, and parasitic coupling occurs between the piezoelectric layer 102 and the substrate 100, resulting in electrical loss, thereby reducing the Q value or electromechanical coupling coefficient (Kt).

[0065] On this basis, the present invention provides an elastic wave resonant device and a method for forming the same, and a filter, wherein the crystal defects in the Bragg reflective layer can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate, thereby effectively suppressing the parasitic coupling phenomenon generated, reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device. In addition, the use of the Bragg reflective layer can effectively reduce acoustic wave leakage, reduce the acoustic energy loss of the elastic wave resonant device, and improve the Q value of the resonant device.

[0066] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0067] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0068] Figures 2 to 6 is a structural schematic diagram of each step of a method for forming an elastic wave resonance device in an embodiment of the present invention; Figure 7 Schematic diagram of a defect of a Frankel vacancy in an embodiment of the present invention; Figure 8 Schematic diagram of a defect of a Schottky vacancy in another embodiment of the present invention.

[0069] Please refer to Figure 2 , providing a substrate 200.

[0070] It should be noted that, in the present embodiment, the substrate 200 mainly plays a supporting role in the subsequent device manufacturing process, and the substrate 200 is made of a material with a resistivity higher than 1000 ohm / cm.

[0071] The material of the substrate 200 includes: single crystal silicon, glass, sapphire, and silicon carbide.

[0072] In this embodiment, the substrate 200 is made of single crystal silicon.

[0073] After providing the substrate 200, the process further includes: forming a piezoelectric layer, a Bragg reflection layer and an electrode structure. For the specific formation process, please refer to Figures 3 to 6 .

[0074] Please refer to Figure 3 , the Bragg reflection layer 201 is formed on one side of the substrate 200 .

[0075] The Bragg reflection layer 201 includes at least two first sub-layers and at least two second sub-layers, the first sub-layers and the second sub-layers are alternately stacked and arranged, and the Bragg reflection layer 201 includes crystal defects.

[0076] In this embodiment, the Bragg reflection layer 201 includes three first sublayers (i.e., first sublayer 2011a, first sublayer 2011b, first sublayer 2011c) and three second sublayers (i.e., second sublayer 2012a, second sublayer 2012b, second sublayer 2012c).

[0077] The crystal defects in the Bragg reflector 201 can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate 200, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device. In addition, the Bragg reflector 201 can effectively reduce acoustic wave leakage, reduce the acoustic energy loss of the elastic wave resonant device, and improve the Q value of the resonant device.

[0078] The crystal defects include: one or more of point defects, line defects, surface defects and lattice mismatch.

[0079] It should be noted that the crystal defects can be formed by common process methods used by those skilled in the art. There are many factors affecting the formation of the crystal defects, such as ion implantation and thermal diffusion, which can both produce crystal point defects.

[0080] Among them, atoms or molecules are ionized to form plasma, which carries a certain amount of charge. The ions are accelerated by the electric field and the magnetic field is used to change their direction of movement, so that the ions can be controlled to enter the crystal with a certain energy. This process will cause a large number of point defects such as vacancies and gaps in the crystal, as well as complex defects formed by vacancies combined with other impurities. The formation of defects is related to the energy, mass, dose, target material and target temperature of the injected ions.

[0081] Crystal defects can also be generated by thermal diffusion, which is divided into interstitial diffusion and substitutional diffusion. At high temperatures, lattice atoms vibrate near the lattice equilibrium position, and matrix atoms have a certain probability of obtaining enough energy to break away from the lattice and become interstitial atoms, creating a vacancy. At this time, the adjacent impurity atoms can occupy this vacancy. This is substitutional diffusion. If the interstitial impurity atoms move from one position to another and do not occupy the lattice point, this is interstitial diffusion. Vacancy defects and impurity defects are easily generated during the diffusion process.

[0082] In this embodiment, the crystal defect is a point defect, and the point defect is a vacancy defect.

[0083] Please refer to Figure 7 In this embodiment, the vacancy defect is a Frankel vacancy.

[0084] Please refer to Figure 8 In other embodiments, the vacancy defect may also be a Schottky vacancy.

[0085] In this embodiment, forming the Bragg emission layer includes: forming the crystal defect at an interface between the first sub-layer and the second sub-layer.

[0086] In this embodiment, the interface is close to the substrate 200, which can keep the crystal defects away from the piezoelectric layer, further suppress the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate 200, reduce electrical losses, and thus improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0087] Please continue to refer to Figure 3 In this embodiment, the crystal defect is located at the interface between the second sub-layer 2012a and the first sub-layer 2011a, and / or the interface between the first sub-layer 2011a and the second sub-layer 2012b.

[0088] In other embodiments, when the number of the first sublayer (i.e., the first sublayer 2011a, the first sublayer 2011b) and the second sublayer (i.e., the second sublayer 2012a, the second sublayer 2012b) is 2 respectively, the crystal defect is located at the interface between the second sublayer 2012a and the first sublayer 2011a.

[0089] In other embodiments, when the number of the first sub-layer and the second sub-layer is respectively greater than 3, the position of the crystal defect is close to the substrate 200, the position of the crystal defect does not exceed the center position of the Bragg reflection layer 201, that is, does not exceed the middle interface between the first sub-layer and the second sub-layer located in the middle, and the crystal defect is located at any one or more interfaces between the first sub-layer and the second sub-layer below the middle interface.

[0090] Please continue to refer to Figure 3 It should be noted that, in the present embodiment, in each group of the composite structure of the first sublayer and the second sublayer (i.e., the first sublayer 2011a and the second sublayer 2012a, the second sublayer 2011b and the second sublayer 2012b, the third sublayer 2011c and the third sublayer 2012c), the second sublayer (i.e., the second sublayer 2012a, the second sublayer 2012b and the second sublayer 2012c) is closer to the substrate 200, and the first sublayer (i.e., the first sublayer 2011a, the first sublayer 2011b and the first sublayer 2011c) is closer to the piezoelectric layer to be formed subsequently, that is, the Bragg reflection layer 201 is formed on the substrate 200 in the stacking order of the second sublayer 2012a, the first sublayer 2011a, the second sublayer 2012b, the first sublayer 2011b... The second sublayer needs to use a high sound velocity material, while the first sublayer needs to use a low sound velocity material. The first sublayer may be made of silicon dioxide, while the second sublayer may be made of tungsten or aluminum nitride.

[0091] In other embodiments, forming the Bragg emission layer includes: forming the crystal defect in the first sub-layer or in the second sub-layer.

[0092] The first sublayer or the second sublayer is close to the substrate 200, which can keep the crystal defects away from the piezoelectric layer, further suppress the parasitic coupling phenomenon between the piezoelectric layer and the substrate 200, reduce electrical losses, and thus improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0093] Please continue to refer to Figure 3 , the crystal defect is located in any one or more of the second sub-layer 2012a, the first sub-layer 2011a and the second sub-layer 2012b.

[0094] When the number of the first sublayer (i.e., the first sublayer 2011a, the first sublayer 2011b) and the second sublayer (i.e., the second sublayer 2012a, the second sublayer 2012b) is 2 respectively, the crystal defect is located in the second sublayer 2012a and / or in the first sublayer 2011a.

[0095] When the number of the first sublayer and the second sublayer is respectively greater than 3, the position of the crystal defect is close to the substrate 200, and the position of the crystal defect does not exceed the center position of the Bragg reflection layer 201, that is, does not exceed the middle interface between the first sublayer and the second sublayer located in the middle, and the crystal defect is located in any one or more of the first sublayer and the second sublayer below the middle interface.

[0096] Please refer to Figure 4 After forming the Bragg reflection layer 201 , the piezoelectric layer 202 is formed.

[0097] The formation of the piezoelectric layer 202 includes: providing an initial piezoelectric layer (not shown), bonding the initial piezoelectric layer and the Bragg reflection layer 201 , and thinning the initial piezoelectric layer to form the piezoelectric layer 202 .

[0098] The process of thinning the initial piezoelectric layer includes: a smart-cut process or a chemical mechanical polishing process.

[0099] In this embodiment, the piezoelectric layer 202 includes a first side 202 a and a second side 202 b opposite to each other. The substrate 200 is located on the first side 202 a . The Bragg reflection layer 201 is located between the substrate 200 and the piezoelectric layer 202 .

[0100] In other embodiments, forming the piezoelectric layer 202 includes: providing an initial piezoelectric layer (not shown), forming the Bragg reflection layer 201 on one side of the initial piezoelectric layer, bonding the Bragg reflection layer 201 and the substrate 200, and thinning the initial piezoelectric layer to form the piezoelectric layer 200.

[0101] In this embodiment, the material of the piezoelectric layer 202 includes but is not limited to at least one of the following: lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate, aluminum nitride, aluminum nitride alloy, gallium nitride, and zinc oxide.

[0102] By adding the Bragg reflection layer 201 and the substrate 200 below the piezoelectric layer 202, the Bragg reflection layer 201 can effectively reduce the leakage of sound waves and reduce the acoustic energy loss of the elastic wave resonance device, thereby improving the Q value of the resonance device. Since the Bragg reflection layer 201 and the substrate 200 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, thereby improving the heat dissipation of the resonance device, increasing the power capacity of the resonance device, and improving the performance of the resonance device.

[0103] Please refer to Figure 5 and Figure 6 , Figure 5 This is a schematic diagram of the structure in which the temperature compensation layer and the protective layer are omitted. Figure 6 yes Figure 5 In the schematic cross-sectional view along line AA, after the piezoelectric layer 202 is formed, an electrode structure 203 is formed. The electrode structure 203 is located on at least one side of the piezoelectric layer 202 .

[0104] In this embodiment, the elastic wave resonance device is a surface acoustic wave resonance device, and the electrode structure 203 is located on the second side 202 b of the piezoelectric layer 202 .

[0105] In this embodiment, forming the electrode structure 203 includes: forming a first bus 2031 and a second bus 2032 arranged in parallel along a first direction X; forming a plurality of first electrode strips 2033 connected to the first bus 2031, wherein the plurality of first electrode strips 2033 are arranged in parallel along a second direction Y, and the first direction X is perpendicular to the second direction Y; forming a plurality of second electrode strips 2034 connected to the second bus 2032, wherein the plurality of second electrode strips 2034 are arranged in parallel along the second direction Y, the first electrode strips 2033 and the second electrode strips 2034 are alternately placed, and along the second direction Y, the first electrode strips 2033 and the second electrode strips 2034 have overlapping areas.

[0106] In this embodiment, the material of the electrode structure 203 includes but is not limited to one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, hafnium, and aluminum.

[0107] Please continue to refer to Figure 6 In this embodiment, it also includes: forming a temperature compensation layer 204 on the piezoelectric layer 202, wherein the temperature compensation layer 204 is located on the second side 202b of the piezoelectric layer 202, and the temperature compensation layer 204 covers the electrode structure 203; forming a protective layer 205 on the temperature compensation layer 204, wherein the protective layer 205 is located on the second side 202b of the piezoelectric layer 202.

[0108] The temperature compensation layer 204 has the opposite temperature frequency shift characteristics to the piezoelectric layer 202, which can reduce the temperature coefficient of frequency (TCF) and tend to 0ppm / r, thereby improving the characteristic of the operating frequency drift of the surface acoustic wave resonator device with the operating temperature, and having higher frequency-temperature stability. The surface acoustic wave resonator device including the temperature compensation layer 204 is called a temperature compensated surface acoustic wave resonator device (i.e., TC-SAW resonator).

[0109] The material of the temperature compensation layer 204 includes silicon dioxide, silicon oxynitride, silicon oxyfluoride or silicon oxycarbide.

[0110] In this embodiment, the material of the temperature compensation layer 204 is silicon dioxide.

[0111] The protection layer 205 is used to protect the electrode structure 203 to prevent oxidation and damage of the electrode structure 203 .

[0112] The material of the protective layer 205 includes, but is not limited to, one of the following: silicon dioxide, silicon nitride, aluminum nitride, silicon oxynitride, aluminum oxide, and silicon carbide.

[0113] In this embodiment, the material of the protection layer 205 is silicon nitride.

[0114] In other embodiments, only the protection layer 205 is formed and located on the second side 202 b of the piezoelectric layer 202 , and the protection layer 205 covers the electrode structure 203 .

[0115] Correspondingly, an elastic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Figure 6, comprising: a substrate 200; a Bragg reflection layer 201, located on the substrate 200, the Bragg reflection layer 201 comprising at least two first sub-layers and at least two second sub-layers, the first sub-layers and the second sub-layers are alternately stacked and arranged, and the Bragg reflection layer 201 comprises crystal defects; a piezoelectric layer 202, located on the Bragg reflection layer 201, the piezoelectric layer 202 comprising a first side 202a and a second side 202b opposite to each other, the Bragg reflection layer 201 and the substrate 200 are located on the first side 202a; an electrode structure 203, located on at least one side of the piezoelectric layer 202.

[0116] The crystal defects in the Bragg reflector 201 can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate 200, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device. In addition, the Bragg reflector 201 can effectively reduce acoustic wave leakage, reduce the acoustic energy loss of the elastic wave resonant device, and improve the Q value of the resonant device.

[0117] In addition, by adding the Bragg reflection layer 201 and the substrate 200 below the piezoelectric layer 202, the Bragg reflection layer 201 can effectively reduce the leakage of sound waves and reduce the acoustic energy loss of the elastic wave resonance device, thereby improving the Q value of the resonance device. Since the Bragg reflection layer 201 and the substrate 200 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, thereby improving the heat dissipation of the resonance device, increasing the power capacity of the resonance device, and improving the performance of the resonance device.

[0118] In this embodiment, the crystal defect is a point defect, and the point defect is a vacancy defect.

[0119] Please refer to Figure 7 In this embodiment, the vacancy defect is a Frankel vacancy.

[0120] Please refer to Figure 8 In other embodiments, the vacancy defect may also be a Schottky vacancy.

[0121] In this embodiment, the crystal defect is located at the interface between the first sub-layer and the second sub-layer of the substrate 200 .

[0122] In this embodiment, the interface is close to the substrate 200, which can keep the crystal defects away from the piezoelectric layer, further suppress the parasitic coupling phenomenon generated between the piezoelectric layer and the substrate 200, reduce electrical losses, and thus improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0123] Please continue to refer to Figure 6 In this embodiment, the Bragg reflection layer 201 includes three layers of the first sub-layers (i.e., the first sub-layer 2011a, the first sub-layer 2011b, and the first sub-layer 2011c) and three layers of the second sub-layers (i.e., the second sub-layer 2012a, the second sub-layer 2012b, and the second sub-layer 2012c). The crystal defect is located at the interface between the second sub-layer 2012a and the first sub-layer 2011a, and / or the interface between the first sub-layer 2011a and the second sub-layer 2012b.

[0124] In other embodiments, when the number of the first sublayer (i.e., the first sublayer 2011a, the first sublayer 2011b) and the second sublayer (i.e., the second sublayer 2012a, the second sublayer 2012b) is 2 respectively, the crystal defect is located at the interface between the second sublayer 2012a and the first sublayer 2011a.

[0125] In other embodiments, when the number of the first sub-layer and the second sub-layer is respectively greater than 3, the position of the crystal defect is close to the substrate 200, the position of the crystal defect does not exceed the center position of the Bragg reflection layer 201, that is, does not exceed the middle interface between the first sub-layer and the second sub-layer located in the middle, and the crystal defect is located at any one or more interfaces between the first sub-layer and the second sub-layer below the middle interface.

[0126] Please continue to refer to Figure 3 It should be noted that, in the present embodiment, in each group of the composite structure of the first sublayer and the second sublayer (i.e., the first sublayer 2011a and the second sublayer 2012a, the second sublayer 2011b and the second sublayer 2012b, the third sublayer 2011c and the third sublayer 2012c), the second sublayer (i.e., the second sublayer 2012a, the second sublayer 2012b and the second sublayer 2012c) is closer to the substrate 200, and the first sublayer (i.e., the first sublayer 2011a, the first sublayer 2011b and the first sublayer 2011c) is closer to the piezoelectric layer to be formed subsequently, that is, the Bragg reflection layer 201 is formed on the substrate 200 in the stacking order of the second sublayer 2012a, the first sublayer 2011a, the second sublayer 2012b, the first sublayer 2011b... The second sublayer needs to use a high sound velocity material, while the first sublayer needs to use a low sound velocity material. The first sublayer may be made of silicon dioxide, while the second sublayer may be made of tungsten or aluminum nitride.

[0127] In other embodiments, the crystal defect is located in the first sub-layer or in the second sub-layer.

[0128] The first sublayer or the second sublayer is close to the substrate 200, which can keep the crystal defects away from the piezoelectric layer, further suppress the parasitic coupling phenomenon between the piezoelectric layer and the substrate 200, reduce electrical losses, and thus improve the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0129] Please continue to refer to Figure 6 , the crystal defect is located in any one or more of the second sub-layer 2012a, the first sub-layer 2011a and the second sub-layer 2012b.

[0130] When the number of the first sublayer (i.e., the first sublayer 2011a, the first sublayer 2011b) and the second sublayer (i.e., the second sublayer 2012a, the second sublayer 2012b) is 2 respectively, the crystal defect is located in the second sublayer 2012a and / or in the first sublayer 2011a.

[0131] When the number of the first sublayer and the second sublayer is respectively greater than 3, the position of the crystal defect is close to the substrate 200, and the position of the crystal defect does not exceed the center position of the Bragg reflection layer 201, that is, does not exceed the middle interface between the first sublayer and the second sublayer located in the middle, and the crystal defect is located in any one or more of the first sublayer and the second sublayer below the middle interface.

[0132] Please continue to refer to Figure 5 and Figure 6 In this embodiment, the electrode structure 203 is located on the second side 202b of the piezoelectric layer 202, and the electrode structure 203 includes: a first bus 2031 and a second bus 2032 arranged in parallel along a first direction X; a plurality of first electrode strips 2033 connected to the first bus 2031, and the plurality of first electrode strips 2033 are arranged in parallel along a second direction Y, and the first direction X is perpendicular to the second direction Y; a plurality of second electrode strips 2034 connected to the second bus 2032, and the plurality of second electrode strips 2034 are arranged in parallel along the second direction Y, the first electrode strips 2033 and the second electrode strips 2034 are staggered, and along the second direction Y, the first electrode strips 2033 and the second electrode strips 2034 have an overlapping area.

[0133] Please continue to refer to Figure 6 In this embodiment, it also includes: a temperature compensation layer 204 located on the piezoelectric layer 202, the temperature compensation layer 204 is located on the second side 202b of the piezoelectric layer 202, and the temperature compensation layer 204 covers the electrode structure 203; a protective layer 205 located on the temperature compensation layer 204, and the protective layer 205 is located on the second side 202b of the piezoelectric layer 202.

[0134] The temperature compensation layer 204 has the opposite temperature frequency shift characteristics to the piezoelectric layer 202, which can reduce the temperature coefficient of frequency (TCF) and tend to 0ppm / r, thereby improving the characteristic of the operating frequency drift of the surface acoustic wave resonator device with the operating temperature, and having higher frequency-temperature stability. The surface acoustic wave resonator device including the temperature compensation layer 204 is called a temperature compensated surface acoustic wave resonator device (i.e., TC-SAW resonator).

[0135] The material of the temperature compensation layer 204 includes silicon dioxide, silicon oxynitride, silicon oxyfluoride or silicon oxycarbide.

[0136] In this embodiment, the material of the temperature compensation layer 204 is silicon dioxide.

[0137] The protection layer 205 is used to protect the electrode structure 203 to prevent oxidation and damage of the electrode structure 203 .

[0138] The material of the protective layer 205 includes, but is not limited to, one of the following: silicon dioxide, silicon nitride, aluminum nitride, silicon oxynitride, aluminum oxide, and silicon carbide.

[0139] In this embodiment, the material of the protection layer 205 is silicon nitride.

[0140] In other embodiments, only the protection layer 205 is formed and located on the second side 202 b of the piezoelectric layer 202 , and the protection layer 205 covers the electrode structure 203 .

[0141] Fig. 9 is a schematic diagram of defects of interstitial impurities in another embodiment of the present invention; Fig.10 Schematic diagram of defects caused by substitutional impurities in another embodiment of the present invention.

[0142] In this embodiment, in the above embodiment ( Figure 6 ) is further described on the basis of the method for forming the elastic wave resonance device, which is different from the above embodiment in that: the point defect is an impurity defect. The following will be specifically described in conjunction with the accompanying drawings.

[0143] Please refer to Fig. 9 In this embodiment, the impurity defects are interstitial impurities.

[0144] Please refer to Fig.10 In other embodiments, the impurity defects are substitutional impurities.

[0145] Correspondingly, an elastic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig. 9 or Fig.10 , the rest of the structure is the same as the elastic wave resonance device described in the above embodiment, except that: the point defect is an impurity defect.

[0146] Please continue to refer to Fig. 9 In this embodiment, the impurity defects are interstitial impurities.

[0147] Please continue to refer to Fig.10 In other embodiments, the impurity defects are substitutional impurities.

[0148] Fig.11 is a schematic diagram of an edge dislocation defect in another embodiment of the present invention; Fig.12 Schematic diagram of a screw dislocation defect in another embodiment of the present invention.

[0149] In this embodiment, in the above embodiment ( Figure 6 ) is further described on the basis of the method for forming the elastic wave resonance device, which is different from the above embodiment in that: the crystal defect is a line defect, and the line defect is a dislocation defect. The following will be specifically described in conjunction with the accompanying drawings.

[0150] The formation of dislocation defects usually includes: due to the influence of temperature gradient, concentration gradient, mechanical vibration, etc., the growing crystal deflects or bends, causing phase differences between adjacent crystal blocks, and dislocations are formed between them; there are a large number of vacancies in the crystal, and the aggregation of vacancies can form dislocations; certain interfaces (such as second phase particles, twins, grain boundaries, etc.) and microcracks inside the crystal often have stress concentration due to the effects of thermal stress and structural stress, and dislocations are easily generated in this area. Dislocation defects can be formed using the process methods commonly used by those skilled in the art.

[0151] Please refer to Fig.11 In this embodiment, the dislocation defect is an edge dislocation.

[0152] Please refer to Fig.12 In other embodiments, the dislocation defect is a screw dislocation.

[0153] Correspondingly, an elastic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig.11 or Fig.12 , the rest of the structure is the same as the elastic wave resonance device described in the above embodiment, the difference is that: the crystal defect is a line defect, and the line defect is a dislocation defect.

[0154] Please continue to refer to Fig.11 In this embodiment, the dislocation defect is an edge dislocation.

[0155] Please continue to refer to Fig.12 In other embodiments, the dislocation defect is a screw dislocation.

[0156] Fig.13 is a schematic diagram of defects in reconstructing atoms in another embodiment of the present invention; Fig.14 It is a schematic diagram of defects on a relaxed surface in another embodiment of the present invention.

[0157] In this embodiment, in the above embodiment ( Figure 6 ) is further described on the basis of the method for forming an elastic wave resonance device, which is different from the above embodiment in that: the crystal defect is a surface defect, and the surface defect includes: a translation interface, a twin interface or a grain boundary. The following will be specifically described in conjunction with the accompanying drawings.

[0158] In this embodiment, the translation interface is a surface state defect.

[0159] It should be noted that, in this embodiment, the surface state defect may be formed at the interface between the first sub-layer and the second sub-layer, for example, by roughening the contact surface between the first sub-layer and the second sub-layer.

[0160] Please refer to Fig.13 In this embodiment, the surface state defect is a reconstructed atom. Reconstructed atoms refer to the periodicity of the surface atomic layer in the horizontal direction being different from that of the atoms in the body, that is, the horizontal spacing between the surface atoms is d1, which is different from the horizontal spacing between the atoms in the body is d2, but the interlayer spacing in the vertical direction is the same as that of the atoms in the body. Reconstructed atomic defects can be formed by roughening (grinding, polishing), heat treatment or homoepitaxial growth, etc., which are commonly used by those skilled in the art.

[0161] Please refer to Fig.14 In other embodiments, the surface state defect is a relaxed surface. A relaxed surface refers to a phenomenon in which the vertical distance d3 between the surface layers is expanded and compressed compared to the vertical distance d4 between the surface and the atomic body, while the horizontal atomic distance is the same. Relaxed surface defects can be formed by annealing, mechanical deformation caused by applying stress, or growth process, etc., which are commonly used by those skilled in the art.

[0162] Correspondingly, an elastic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig.13 or Fig.14 , the rest of the structure is the same as the elastic wave resonance device described in the above embodiment, the difference is that: the crystal defect is a surface defect, and the surface defect includes: a translation interface, a twin interface or a grain boundary.

[0163] In this embodiment, the translation interface is a surface state defect.

[0164] It should be noted that, in this embodiment, the surface state defect may be formed at the interface between the first sub-layer and the second sub-layer, for example, by roughening the contact surface between the first sub-layer and the second sub-layer.

[0165] Please refer to Fig.13 In this embodiment, the surface state defects are reconstructed atoms. Reconstructed atoms refer to the periodicity of the surface atomic layer in the horizontal direction being different from that of the atoms in the body, that is, the horizontal spacing between the surface atoms is d1, which is different from the horizontal spacing between the atoms in the body is d2, but the interlayer spacing in the vertical direction is the same as that of the atoms in the body.

[0166] Please refer to Fig.14 In other embodiments, the surface state defect is a relaxed surface. A relaxed surface refers to a phenomenon in which the vertical distance d3 between surface layers is expanded and compressed compared to the vertical distance d4 between the surface and the atomic body, while the horizontal atomic distance is the same.

[0167] Fig.15 It is a schematic diagram of lattice mismatch defects in another embodiment of the present invention.

[0168] In this embodiment, in the above embodiment ( Figure 6 ) is further described on the basis of the method for forming the elastic wave resonance device, which is different from the above embodiment in that: the crystal defect is a lattice mismatch. The following will be specifically described in conjunction with the accompanying drawings.

[0169] Please refer to Fig.15 In this embodiment, there is a lattice mismatch between the materials of the first sub-layer and the second sub-layer. The lattice mismatch is a mismatch phenomenon caused by the different lattice constants between the first sub-layer and the second sub-layer.

[0170] It should be noted that, in this embodiment, the lattice mismatch between the first sub-layer and the second sub-layer is greater than 5%.

[0171] In this embodiment, the material combination of the first sublayer / the second sublayer can be: silicon / carbon, silicon / gallium nitride, silicon / silicon carbide or gallium nitride / sapphire, or the material combination of the second sublayer / the first sublayer can be: silicon / carbon, silicon / gallium nitride, silicon / silicon carbide or gallium nitride / sapphire.

[0172] Correspondingly, an elastic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig.15 , the rest of the structure is the same as the elastic wave resonance device described in the above embodiment, the difference is that: the crystal defect lattice mismatch.

[0173] Please refer to Fig.15In this embodiment, there is a lattice mismatch between the materials of the first sub-layer and the second sub-layer. The lattice mismatch is a mismatch phenomenon caused by the different lattice constants between the first sub-layer and the second sub-layer.

[0174] It should be noted that, in this embodiment, the lattice mismatch between the first sub-layer and the second sub-layer is greater than 5%.

[0175] In this embodiment, the material combination of the first sublayer / the second sublayer can be: silicon / carbon, silicon / gallium nitride, silicon / silicon carbide or gallium nitride / sapphire, or the material combination of the second sublayer / the first sublayer can be: silicon / carbon, silicon / gallium nitride, silicon / silicon carbide or gallium nitride / sapphire.

[0176] Figures 16 to 20 It is a structural schematic diagram of each step of a method for forming an elastic wave resonance device in another embodiment of the present invention.

[0177] Please refer to Fig.16 , providing a substrate 300.

[0178] It should be noted that, in this embodiment, the substrate 300 mainly plays a supporting role in the subsequent device manufacturing process, and the substrate 300 is made of a material with a resistivity higher than 1000 ohm / cm.

[0179] The material of the substrate 300 includes: single crystal silicon, glass, sapphire, and silicon carbide.

[0180] In this embodiment, the substrate 300 is made of single crystal silicon.

[0181] After providing the substrate 200 , a Bragg reflection layer is formed between the substrate 300 and a piezoelectric layer to be formed subsequently.

[0182] Please refer to Fig.17 , the Bragg reflection layer 301 is formed on one side of the substrate 300 .

[0183] In this embodiment, the Bragg reflection layer 301 includes at least two first sub-layers 3011 and at least two second sub-layers 3012 , the first sub-layers 3011 and the second sub-layers 3012 are alternately stacked and arranged, and the Bragg reflection layer 301 includes crystal defects.

[0184] The crystal defects in the Bragg reflector 301 can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate 300, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device. In addition, the Bragg reflector 301 can effectively reduce acoustic wave leakage, reduce the acoustic energy loss of the elastic wave resonant device, and improve the Q value of the resonant device.

[0185] In this embodiment, the specific form of the crystal defect can be Figures 7 to 15 Any one, please refer to Figures 7 to 15 The relevant instructions are as described above and will not be repeated here.

[0186] In this embodiment, please refer to the relevant description of the Bragg emission layer. Figure 6 The relevant description will not be repeated here.

[0187] After forming the Bragg reflection layer 301, a piezoelectric layer and an electrode structure are formed, wherein the electrode structure is located on at least one side of the piezoelectric layer. Figures 18 to 20 .

[0188] In this embodiment, the elastic wave resonator device is a bulk acoustic wave resonator device (SMR-BAW).

[0189] After the Bragg reflection layer 301 is formed, a first electrode layer is formed. The Bragg reflection layer 301 is located between the substrate 300 and the first electrode layer.

[0190] Please refer to Fig.18 , a first electrode layer 3031 is formed on the Bragg reflection layer 301 .

[0191] In this embodiment, the material of the first electrode layer 3031 includes but is not limited to at least one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, hafnium, and aluminum.

[0192] After forming the first electrode layer 3031 , a piezoelectric layer is formed, wherein the first electrode layer 3031 is located between the piezoelectric layer and the Bragg reflection layer 301 .

[0193] Please refer to Fig.19 After forming the first electrode layer 3031 , a piezoelectric layer 302 is formed on the first electrode layer 3031 .

[0194] In this embodiment, the piezoelectric layer 302 includes a first side 302 a and a second side 302 b that are opposite to each other. The substrate 300 , the Bragg emission layer and the first electrode layer 3031 are all located on the first side 302 a of the piezoelectric layer 302 .

[0195] In this embodiment, the material of the piezoelectric layer 302 includes but is not limited to at least one of the following: lithium tantalate, lithium niobate, lead zirconate titanate, lead magnesium niobate-lead titanate, aluminum nitride, aluminum nitride alloy, gallium nitride, and zinc oxide.

[0196] By adding the Bragg reflection layer 301 and the substrate 300 below the piezoelectric layer 302, the Bragg reflection layer 201 can effectively reduce the leakage of sound waves and reduce the acoustic energy loss of the elastic wave resonance device, thereby improving the Q value of the resonance device. Since the Bragg reflection layer 301 and the substrate 300 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, thereby improving the heat dissipation of the resonance device, increasing the power capacity of the resonance device, and improving the performance of the resonance device.

[0197] After the piezoelectric layer is formed, a second electrode layer is formed on the second side 302 b of the piezoelectric layer 302 .

[0198] Please refer to Fig. 20 , a second electrode layer 3032 is formed on the piezoelectric layer 302 .

[0199] In this embodiment, the second electrode layer 3032 is located on the second side 302 b of the piezoelectric layer 302 , and projections of the first electrode layer 3031 and the second electrode layer 3032 toward the substrate 300 have an overlapping area.

[0200] In this embodiment, the electrode structure 303 is formed by the first electrode layer 3031 and the second electrode layer 3032 . The electrode structure 303 is located on the first side 302 a and the second side 302 b of the piezoelectric layer 302 .

[0201] In this embodiment, the material of the second electrode layer 3032 includes but is not limited to at least one of the following: molybdenum, tungsten, copper, platinum, rhenium, osmium, iridium, tantalum, gold, hafnium, and aluminum.

[0202] In this embodiment, a passivation layer (not shown) is formed on the surface of the second electrode layer 3032 to enhance the protection of the second electrode layer 3032 .

[0203] Correspondingly, an elastic wave resonance device is also provided in the embodiment of the present invention, please continue to refer to Fig. 20, comprising: a substrate 300; a Bragg reflection layer 301, located on the substrate 300, the Bragg reflection layer 301 comprising at least two first sub-layers 3011 and at least two second sub-layers 3012, the first sub-layers 3011 and the second sub-layers 3012 are alternately stacked and arranged, and the Bragg reflection layer 301 comprises crystal defects; a piezoelectric layer 302, located on the Bragg reflection layer 301, the piezoelectric layer 302 comprises a first side 302a and a second side 302b opposite to each other, the Bragg reflection layer 301 and the substrate 300 are located on the first side 302a; an electrode structure 303, located on both sides of the piezoelectric layer 302.

[0204] The crystal defects in the Bragg reflection layer 301 can form charge traps, which can prevent the formation of a conductive plane on the surface of the substrate 300, thereby effectively suppressing the parasitic coupling phenomenon and reducing electrical losses, thereby improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0205] In addition, by adding the Bragg reflection layer 301 and the substrate 300 below the piezoelectric layer 302, the Bragg reflection layer 301 can effectively reduce the leakage of sound waves and reduce the acoustic energy loss of the elastic wave resonance device, thereby improving the Q value of the resonance device. Since the Bragg reflection layer 301 and the substrate 300 are solid materials, their heat transfer coefficient is greater than the heat transfer coefficient of air, thereby improving the heat dissipation of the resonance device, increasing the power capacity of the resonance device, and improving the performance of the resonance device.

[0206] In this embodiment, the specific form of the crystal defect can be Figures 7 to 15 Any one, please refer to Figures 7 to 15 The relevant instructions are as described above and will not be repeated here.

[0207] In this embodiment, please refer to the relevant description of the Bragg emission layer. Figure 6 The relevant description will not be repeated here.

[0208] In this embodiment, the elastic wave resonator device is a bulk acoustic wave resonator device (SMR-BAW).

[0209] Please continue to refer to Fig. 20In this embodiment, the electrode structure 303 includes: a first electrode layer 3031, located on the Bragg reflection layer 301, the first electrode layer 3031 is located on the first side 302a of the piezoelectric layer 302; a second electrode layer 3032, located on the second side 302b of the piezoelectric layer 302, and the projections of the first electrode layer 3031 and the second electrode layer 3032 toward the substrate 300 have an overlapping area. That is, the electrode structure 303 is located on the first side 302a and the second side 302b of the piezoelectric layer 302.

[0210] Fig.21 It is a schematic structural diagram of an elastic wave resonance device in another embodiment of the present invention.

[0211] In this embodiment, in the above embodiment ( Figure 6 or Fig. 20 ) is further described on the basis of the method for forming the elastic wave resonance device, which is different from the above embodiment in that: an isolation layer is further provided between the substrate and the Bragg reflection layer. The following will be specifically described in conjunction with the accompanying drawings

[0212] Please continue to refer to Fig.21 , Fig.21 To omit the schematic diagram of the piezoelectric layer and the electrode structure, the material of the isolation layer 400 includes but is not limited to one of the following: silicon dioxide, silicon nitride, silicon carbide or an amorphous insulating material.

[0213] In this embodiment, the isolation layer 400 is made of silicon dioxide.

[0214] In this embodiment, the thickness of the isolation layer 400 is less than 2 nm, or is between 30 nm and 30 um.

[0215] In this embodiment, the isolation layer 400 is formed on the substrate 200 ( 300 ), and the Bragg reflection layer 201 ( 301 ) is formed on the isolation layer 400 .

[0216] In other embodiments, the isolation layer 400 is formed on the substrate 200 (300), and the isolation layer 400 is bonded to the Bragg reflection layer 201 (301).

[0217] In other embodiments, the isolation layer 400 may be formed on one side of the Bragg reflection layer 201 (301), and then the isolation layer 400 may be bonded to the substrate 200 (300).

[0218] By forming the isolation layer 400 between the substrate 200 (300) and the Bragg reflection layer 201 (301), the isolation layer 400 can block the heat transferred from the substrate 200 (300) in the subsequent heat treatment process, thereby preventing the crystal defects in the Bragg reflection layer 201 (301) from being repaired due to heat, thereby causing the performance of the Bragg reflection layer 201 (301) to be reduced in capturing charges, thereby ensuring the capture performance of the Bragg reflection layer 201 (301) and improving the Q value of the resonant device or the electromechanical coupling coefficient (Kt) of the resonant device.

[0219] Correspondingly, an embodiment of the present invention further provides a filter, comprising: an elastic wave resonance device as described in any one of the above embodiments.

[0220] It should be understood that the examples and embodiments herein are merely illustrative and that various modifications and corrections may be made by those skilled in the art without departing from the spirit and scope of the present invention as defined in this application and the appended claims.

Claims

1. An elastic wave resonance device, characterized in that: include: substrate; A Bragg reflection layer, located on the substrate, the Bragg reflection layer comprises at least two first sub-layers and at least two second sub-layers, the first sub-layers and the second sub-layers are alternately stacked and arranged, and the Bragg reflection layer comprises crystal defects; a piezoelectric layer, located on the Bragg reflective layer, the piezoelectric layer comprising a first side and a second side opposite to each other, the Bragg reflective layer and the substrate being located on the first side; The electrode structure is located on at least one side of the piezoelectric layer.

2. The elastic wave resonance device according to claim 1, characterized in that: The material of the first sub-layer is silicon dioxide; the material of the second sub-layer is tungsten or aluminum nitride.

3. The elastic wave resonance device according to claim 1, characterized in that: The crystal defect is located at an interface between the first sub-layer and the second sub-layer.

4. The elastic wave resonance device according to claim 3, characterized in that: The interface is proximate to the substrate.

5. The elastic wave resonance device according to claim 1, characterized in that: The crystal defect is located in the first sub-layer or in the second sub-layer.

6. The elastic wave resonance device according to claim 5, characterized in that: The first sub-layer or the second sub-layer is close to the substrate.

7. The elastic wave resonance device according to claim 1, characterized in that: The crystal defects include: one or more of point defects, line defects, surface defects and lattice mismatch.

8. The elastic wave resonance device according to claim 7, characterized in that: The point defects include: vacancy defects or impurity defects.

9. The elastic wave resonance device according to claim 8, characterized in that: The vacancy defects include Frankel vacancies or Schottky vacancies.

10. The elastic wave resonance device according to claim 8, characterized in that: The impurity defects include interstitial impurities or substitutional impurities.

11. The elastic wave resonance device according to claim 7, characterized in that: The line defects include: dislocation defects.

12. The elastic wave resonance device according to claim 11, characterized in that: The dislocation defect includes edge dislocation or screw dislocation.

13. The elastic wave resonance device according to claim 7, characterized in that: The surface defects include: translational interfaces, twin interfaces or grain boundaries.

14. The elastic wave resonance device according to claim 13, wherein: The translation interface includes: surface state defects.

15. The elastic wave resonance device according to claim 14, characterized in that: The surface state defects include: reconstructed atoms or relaxed surfaces.

16. The elastic wave resonance device according to claim 7, characterized in that: There is a lattice mismatch between materials of the first sub-layer and the second sub-layer.

17. The elastic wave resonance device according to claim 16, wherein: The lattice mismatch between the first sub-layer and the second sub-layer is greater than 5%.

18. The elastic wave resonance device according to claim 1, wherein: The electrode structure is located on the second side of the piezoelectric layer, and the electrode structure includes: a first bus and a second bus arranged in parallel along a first direction; a plurality of first electrode strips connected to the first bus, and the plurality of first electrode strips are arranged in parallel along a second direction, and the first direction is perpendicular to the second direction; a plurality of second electrode strips connected to the second bus, and the plurality of second electrode strips are arranged in parallel along the second direction, the first electrode strips and the second electrode strips are staggered, and the first electrode strips and the second electrode strips have an overlapping area along the second direction.

19. The elastic wave resonance device according to claim 18, wherein: Also includes: A protective layer is located on the piezoelectric layer and covers the electrode structure.

20. The elastic wave resonance device according to claim 18, wherein: Also includes: The temperature compensation layer is located on the piezoelectric layer and covers the electrode structure.

21. The elastic wave resonance device according to claim 1, wherein: The electrode structure includes: a first electrode layer located on the Bragg reflection layer, the first electrode layer is located on a first side of the piezoelectric layer; a second electrode layer is located on a second side of the piezoelectric layer, and projections of the first electrode layer and the second electrode layer toward the substrate have an overlapping area.

22. A method for forming an elastic wave resonance device, characterized in that: include: providing a substrate; forming a piezoelectric layer, the piezoelectric layer comprising a first side and a second side opposite each other, the substrate being located on the first side; forming a Bragg reflection layer located between the substrate and the piezoelectric layer, wherein the Bragg reflection layer comprises at least two first sub-layers and at least two second sub-layers, the first sub-layers and the second sub-layers are alternately stacked and arranged, and the Bragg reflection layer comprises crystal defects; An electrode structure is formed, which is located on at least one side of the piezoelectric layer.

23. The method for forming an elastic wave resonator according to claim 22, wherein: Forming the Bragg emission layer includes forming the crystal defect at an interface between the first sub-layer and the second sub-layer.

24. The method for forming an elastic wave resonator according to claim 23, wherein: The interface is proximate to the substrate.

25. The method for forming an elastic wave resonator according to claim 22, wherein: Forming the Bragg emission layer includes: forming the crystal defects in the first sub-layer or in the second sub-layer.

26. The method for forming an elastic wave resonator according to claim 25, wherein: The first sub-layer or the second sub-layer is close to the substrate.

27. The method for forming an elastic wave resonator according to claim 22, wherein: The crystal defects include: one or more of point defects, line defects, surface defects and lattice mismatch.

28. The method for forming an elastic wave resonator according to claim 27, wherein: There is a lattice mismatch between materials of the first sub-layer and the second sub-layer.

29. The method for forming an elastic wave resonator according to claim 28, wherein: The lattice mismatch between the first sub-layer and the second sub-layer is greater than 5%.

30. The method for forming an elastic wave resonator according to claim 22, wherein: The Bragg reflection layer is formed on one side of the substrate, and the piezoelectric layer and the Bragg reflection layer are bonded.

31. The method for forming an elastic wave resonator according to claim 22, wherein: The Bragg reflection layer is formed on a first side of the piezoelectric layer, and the Bragg reflection layer and the substrate are bonded.

32. The method for forming an elastic wave resonator according to claim 22, wherein: The electrode structure is located on the second side of the piezoelectric layer, and forming the electrode structure includes: forming a first bus and a second bus arranged in parallel along a first direction; forming a plurality of first electrode strips connected to the first bus, wherein the plurality of first electrode strips are arranged in parallel along a second direction, and the first direction is perpendicular to the second direction; forming a plurality of second electrode strips connected to the second bus, wherein the plurality of second electrode strips are arranged in parallel along the second direction, the first electrode strips and the second electrode strips are staggered, and the first electrode strips and the second electrode strips have an overlapping area along the second direction.

33. The method for forming an elastic wave resonator according to claim 32, wherein: Also includes: A protection layer is formed, which is located on the second side of the piezoelectric layer and covers the electrode structure.

34. The method for forming an elastic wave resonator according to claim 32, wherein: Also includes: A temperature compensation layer is formed, which is located on the second side of the piezoelectric layer and covers the electrode structure.

35. The method for forming an elastic wave resonator according to claim 22, wherein: Forming the electrode structure includes: forming a first electrode layer located on a first side of the piezoelectric layer, the Bragg reflection layer being located between the substrate and the first electrode layer; forming a second electrode layer located on a second side of the piezoelectric layer, the projections of the first electrode layer and the second electrode layer toward the substrate having an overlapping area.

36. A filter, characterized in that: include: An elastic wave resonance device as claimed in any one of claims 1 to 21.

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