Ceramic substrate, composite piezoelectric substrate, electronic device, and module

Abstract

The embodiment of the invention provides a ceramic substrate, a composite piezoelectric substrate, an electronic device and a module, the ceramic substrate comprises a ceramic material base body, and the ceramic material base body is provided with a first surface and a second surface which are opposite to each other; a doping layer which extends by a preset thickness from the first surface to the direction gradually close to the second surface is formed in the ceramic material matrix; the doping layer comprises a target doping element doped in the ceramic material matrix, and the doping concentration range of the target doping element in the doping layer is 1 * 10 < 17 > ions / cm < 3 > to 5 * 10 < 20 > ions / cm < 3 >. According to the elastic wave device provided by the embodiment of the invention, the Q value can be improved, and the insertion loss can be improved.

Description

Technical Field

[0001] This invention relates to the field of electronic device technology, and in particular to a ceramic substrate, a composite piezoelectric substrate, electronic devices, and modules. Background Technology

[0002] In some elastic wave devices, such as SAW (surface acoustic wave) devices, a composite piezoelectric substrate consisting of a ceramic substrate and a piezoelectric material layer is used to improve temperature characteristics. However, because the wave in the piezoelectric material layer of the SAW device leaks through the ceramic substrate during propagation, it affects the device's quality factor (Q value) and insertion loss. Summary of the Invention

[0003] The purpose of this invention is to alleviate the problem of acoustic wave leakage in elastic wave devices, and to provide a ceramic substrate, a composite piezoelectric substrate, electronic devices and modules that can improve the Q value and reduce insertion loss.

[0004] One embodiment of the present invention provides a ceramic substrate, the ceramic substrate comprising a ceramic material matrix having opposing first and second surfaces; a doped layer of a predetermined thickness is formed in the ceramic material matrix extending from the first surface toward the second surface, the doped layer comprising a target dopant element doped in the ceramic material matrix; the doping concentration of the target dopant element in the doped layer is in the range of 1×10⁻⁶. 17 ions / cm 3 ~5×10 20 ions / cm 3 .

[0005] An embodiment of the present invention provides a composite piezoelectric substrate, including the aforementioned ceramic substrate, and further including: a piezoelectric material layer disposed on the side of the first surface facing away from the second surface; and an electrode located on the side of the piezoelectric material layer facing away from the ceramic substrate.

[0006] One embodiment of the present invention provides an electronic device including the aforementioned composite piezoelectric substrate.

[0007] One embodiment of the present invention provides a module including a wiring substrate, a plurality of external connection terminals, an inductor and a sealing portion, as well as the aforementioned electronic devices.

[0008] The above embodiments of the present invention have at least one or more of the following beneficial effects: by forming a doped layer with a target doping element having a specific doping concentration range on the side of the ceramic substrate near the piezoelectric material layer, the doped layer can enrich more acoustic wave energy in the piezoelectric material layer, thereby improving the Q value and reducing insertion loss. Attached Figure Description

[0009] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0010] Figure 1 This is a schematic diagram of the structure of a ceramic substrate provided in one embodiment of the present invention.

[0011] Figure 2 This is a schematic diagram of the structure of a composite piezoelectric substrate provided in one embodiment of the present invention.

[0012] Figure 3 This is a schematic diagram of the structure of an electronic device provided in one embodiment of the present invention.

[0013] Figure 4 for Figure 3 The diagram shows the fabrication process of the electronic device.

[0014] Figure 5 This is a comparison chart of the Q values ​​of Example 1 and Comparative Example 1 of the present invention.

[0015] Figure 6 This is a comparison diagram of the insertion loss of Embodiment 1 and Comparative Example 1 of the present invention.

[0016] Figure 7 A schematic diagram of the structure of an electronic device provided for another embodiment of the present invention.

[0017] Figure 8 This is a schematic diagram of the structure of another electronic device provided in an embodiment of the present invention.

[0018] Figure 9 This is a schematic diagram of another electronic device provided in an embodiment of the present invention.

[0019] Figure 10 This is a schematic diagram of the structure of a module provided in one embodiment of the present invention.

[0020] [Explanation of Labels in the Attached Images]

[0021] 1000, Module; 100, Electronic Component; 10, Composite Piezoelectric Substrate; 11, Ceramic Substrate; 110, Ceramic Material Matrix; 111, First Surface; 112, Second Surface; 113, Doped Layer; 114, Crystal Layer; 12, Piezoelectric Material Layer; 121, Third Surface; 13, Intermediate Layer; 20, Electrode; 21, IDT Electrode; 22, Electrode Pad; 30, Packaging Substrate; 41, First Sealing Structure; 42, Second Sealing Structure; 51, Bump; 52, First Conductive Part; 53, First External Terminal Electrode; 54, Second Conductive Part; 55, Second External Terminal Electrode; 60, Gap; 70, Cover; 400, Inductor; 500, Sealing Part; 600, Integrated Circuit Component; 700, Wiring Substrate; 701, External Connection Terminal. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] It should also be noted that the division of multiple embodiments in this invention is only for the convenience of description and should not constitute a special limitation. Features in various embodiments can be combined and referenced in each other without contradiction.

[0026] like Figure 3 As shown, an embodiment of the present invention provides an electronic device 100, including a ceramic substrate 11, a piezoelectric material layer 12, and electrodes 20. (Refer to...) Figure 1 In this embodiment, the ceramic substrate 11 includes a ceramic material matrix 110, which has a first surface 111 and a second surface 112 facing each other. A doped layer 113 of a predetermined thickness is formed within the ceramic material matrix 110, extending from the first surface 111 towards the second surface 112. The doped layer 113 includes a target dopant element doped in the ceramic material matrix 110. In some embodiments, the doping concentration of the target dopant element in the doped layer 113 is in the range of 1×10⁻⁶. 17 ions / cm 3 ~5×10 20 ions / cm 3 For example, it could be 1.67 × 10⁻⁶.17 ions / cm 3 3.33×10 17 ions / cm 3 5.33×10 18 ions / cm 3 5×10 18 ions / cm 3 6.67×10 18 ions / cm 3 In the electronic device 100, a piezoelectric material layer 12 is disposed on the side of the first surface 111 facing away from the second surface 112. The piezoelectric material layer 12 and the ceramic substrate 11 together constitute a composite piezoelectric substrate 10. In the electronic device 100, an electrode 20 is located on the side of the piezoelectric material layer 12 facing away from the ceramic substrate 11.

[0027] Among them, the ceramic material matrix 110 is, for example, a polycrystalline material, specifically any one of polycrystalline magnesium aluminum spinel, polycrystalline sapphire, polycrystalline aluminum nitride, polycrystalline magnesium oxide, polycrystalline quartz, and polycrystalline silicon carbide.

[0028] The doped layer 113 is obtained by introducing foreign atoms or ions into the ceramic material matrix 110 to change the physical, chemical, or electrical properties of the ceramic material matrix 110, such as altering the crystal structure (lattice distortion), surface roughness, defect distribution, chemical composition, and conductivity. The doped layer 113 contains the constituent elements of the ceramic material matrix 110 and also contains the target doping element. Specifically, the doped layer 113 is formed by implanting the target doping element into the ceramic material matrix 110 from the first surface 111. The doped layer 113 contains all the constituent elements of the ceramic material matrix 110, and can also be understood as the doped layer 113 being based on the ceramic material matrix 110 and containing the target doping element. After implanting the target doping element into the ceramic material matrix 110, the portion of the target doped element implanted (e.g., Figure 1 An amorphous layer (i.e., a doped layer 113) is formed on the upper layer of the ceramic substrate 11, and the portion without implanted target dopant elements (such as...) Figure 1 The lower layer (i.e., the crystal layer 114) in the ceramic substrate 11 retains the original structure of the ceramic material matrix 110.

[0029] The target doping element can be the same as or different from the constituent elements of the ceramic material substrate 110. The target doping element can be any one or more of nitrogen, boron, phosphorus, and carbon. For example, if the ceramic material substrate 110 is polycrystalline magnesium aluminum spinel and the target doping element is nitrogen, then the doped layer 113 is a nitrogen-doped MgAl2O4 layer, and the crystal layer 114 is a MgAl2O4 layer. The target doping element described above can effectively increase the compressive stress on the surface layer of the ceramic material substrate 110 (the region extending a predetermined thickness from the first surface 111 to the second surface 112), increasing the material hardness and elastic modulus of the obtained ceramic substrate 11, reducing the mechanical loss of surface acoustic waves during propagation, thereby improving the Q value of the device. The position of the doped layer 113 is such that it extends a predetermined thickness from the first surface 111 to the second surface 112; that is, the region in the ceramic material substrate 110 where lattice distortion occurs is located on the surface layer of the ceramic material substrate 110, having a smaller impact on the deeper layers of the ceramic material substrate 110 (i.e., the region where the crystal layer 114 is located).

[0030] Reference Figure 3 The preset thickness is marked as D1, and the value of D1 is the distance from the first surface 111 to the interface between the doped layer 113 and the crystal layer 114.

[0031] The piezoelectric material layer 12 is made of a different material than the ceramic substrate 11. Specifically, the piezoelectric material layer 12 is made of lithium tantalate or lithium niobate. The Young's modulus of the piezoelectric material layer 12 is less than that of the ceramic substrate 11. When lithium tantalate is used, the Young's modulus is 10–20 GPa; when lithium niobate is used, the Young's modulus is 170–210 GPa. The ceramic substrate 11 and the piezoelectric material layer 12 together constitute... Figure 2 The composite piezoelectric substrate 10 shown is, according to Figure 2 or Figure 3 The piezoelectric material layer 12 is positioned on the first surface 111 of the ceramic substrate 11. In the composite piezoelectric substrate 10, the doped layer 113 is located between the crystal layer 114 and the piezoelectric material layer 12. The ceramic substrate 11 and the piezoelectric material layer 12 can be directly bonded by van der Waals forces. The piezoelectric material layer 12 includes a third surface 121 facing away from the ceramic substrate 11, and an electrode 20 is disposed on the third surface 121. The electrode 20 may include an IDT electrode 21. IDT stands for interdigital transducer, and the electronic device 100 is specifically an elastic wave device, more specifically a SAW device.

[0032] The fabrication process of the electronic device 100 provided in this embodiment can be referred to Figure 4As shown, (1) a ceramic material substrate 110 is provided, the ceramic material substrate 110 having a first surface 111 and a second surface 112 opposite to each other. (2) A target doping element is implanted into the ceramic material substrate 110 from the first surface 111 using a doping source containing the target doping element. For example, if the target doping element is nitrogen, nitrogen gas can be used as the doping source to bombard the first surface 111. After the target doping element is implanted, two layers, a doped layer 113 and a crystal layer 114, are formed in the ceramic material substrate 110 to obtain a ceramic substrate 11. (3) A piezoelectric material layer 12 is formed on the first surface 111 of the ceramic substrate 11. The ceramic substrate 11 and the piezoelectric material layer 12 can be combined by direct bonding. After bonding, the piezoelectric material layer 12 is thinned to obtain a composite piezoelectric substrate 10. (4) An electrode 20 is formed on the piezoelectric material layer 12 to obtain an electronic device 100. Annealing is not required between steps (2) and (4), and voids should be prevented from forming in the ceramic substrate 11 as much as possible to avoid affecting the Q value due to voids.

[0033] In some embodiments, the Young's modulus of the ceramic substrate 11 is 294–392 GPa. In other embodiments, the Young's modulus of the ceramic substrate 11 is greater than that of the ceramic material matrix 110. This greater Young's modulus of the ceramic substrate 11 compared to the ceramic material matrix 110 can also be understood as the portion of the formed doped layer 113 having a higher Young's modulus than the original ceramic material matrix 110 (also called the original ceramic material matrix), resulting in an increase in the overall Young's modulus of the ceramic substrate 11 compared to the original ceramic material matrix 110. The Young's modulus of the ceramic material matrix 110 can be determined by testing the constituent materials of the ceramic material matrix 110. For example, if the ceramic material matrix 110 is polycrystalline magnesium aluminum spinel, the Young's modulus of the ceramic material matrix 110 can be determined based on the Young's modulus of the polycrystalline magnesium aluminum spinel. For example, the Young's modulus of the ceramic substrate 110 is 278–280 GPa. After the formation of the doped layer 113, the Young's modulus of the ceramic substrate 11 increases to 294–392 GPa (for example, 294 GPa, 300 GPa, 320 GPa, 370 GPa, etc.). In this embodiment, by forming a doped layer 113 with the target doping element in the ceramic substrate 11, the ceramic substrate can be modified, thereby increasing the Young's modulus of the ceramic substrate 11 facing the piezoelectric material layer 12. This allows more acoustic energy to be enriched in the piezoelectric material layer 12, thus improving the Q value.

[0034] In some embodiments, the Young's modulus of the ceramic substrate 11 is 1.05 to 1.5 times that of the ceramic material matrix 110. Examples include 1.05 times, 1.1 times, 1.2 times, 1.4 times, etc., but are not limited to these examples. Within the range provided in this embodiment, as the multiple increases, the difference in Young's modulus between the ceramic substrate 11 and the original ceramic material matrix 110 also increases. Controlling the Young's modulus of the ceramic substrate 11 to within 1.5 times that of the ceramic material matrix 110 can avoid stray or other parameter abnormalities.

[0035] In some embodiments, the Young's modulus of the ceramic substrate 11 is greater than 300 GPa, which is more conducive to improving the Q value of the electronic component.

[0036] You can refer to Figure 5 and Figure 6 The comparison shows the Q value and insertion loss between Embodiment 1 and Comparative Example 1 of this application. Embodiment 1 is a specific embodiment of the electronic device 100 of this application, where the preset thickness D1 of the doped layer 113 is 121.61 nm. In Comparative Example 1, the ceramic substrate has no doped layer, and the other parameters are the same. Figure 5 The horizontal axis represents Frequency (MHz), and the vertical axis represents the Q value, according to... Figure 5 It can be seen that, in the range of 900MHz to 930MHz, the Q value of Example 1 is significantly higher than that of Comparative Example 1. The maximum Q value in Example 1 is 3255.5, while the maximum Q value in Comparative Example 1 is 2729.0, representing a 19% improvement in Q value compared to Comparative Example 1. Figure 6 The horizontal axis represents Frequency (MHz), and the vertical axis represents Admittance (dB). According to... Figure 6 It can be seen that the minimum insertion loss of Example 1 (expressed as insertion loss, with higher admittance resulting in lower insertion loss) is -0.499, while the minimum insertion loss of Comparative Example 1 is -0.542. The minimum insertion loss of Example 1 is 8.6% better than that of the Comparative Example. Therefore, the electronic device 100 provided by the embodiments of the present invention can achieve better electrical performance.

[0037] In some embodiments, the preset thickness D1 is 0.025λ to 2λ, where λ is the wavelength of the elastic wave determined by the electrode period of the IDT electrode 21. For example, D1 can be 0.05λ, 0.1λ, 0.15λ, 0.3λ, 0.5λ, 0.8λ, 1.2λ, 1.5λ, 2.0λ, etc. In some embodiments, the preset thickness D1 is 0.025λ to λ, more specifically, it can be 0.025λ to 0.5λ. Within the preset thickness range provided in this embodiment, leakage of the primary mode sound velocity can be effectively prevented, and scattering of higher-order mode clutter can be prevented, thus preventing the generation of stray waves.

[0038] Table 1 shows the parameters of the electronic device 100 provided in some embodiments (embodiments 2 to 5) of this application (Young's modulus refers to the Young's modulus of the ceramic substrate 11 forming the electronic device 100, and the insertion loss is expressed as admittance, with the minimum insertion loss shown in the table).

[0039] Table 1:

[0040]

[0041]

[0042] According to the data in Table 1, after the electronic device 100 provided in this embodiment forms the doped layer 113, the Young's modulus of the ceramic substrate 11 reaches more than 300 GPa. Moreover, the larger the preset thickness of the formed doped layer 113 is, the larger the Young's modulus of the ceramic substrate 11 becomes. The electronic devices 100 provided in Embodiments 2 to 5 all have high Q values ​​and low insertion losses.

[0043] In some embodiments, the concentration range of the target dopant element within the doped layer 113 is specifically 5 × 10⁻⁶. 17 ions / cm 3 ~1×10 20 ions / cm 3 This method effectively improves the Q-value while avoiding excessive warpage of the ceramic substrate 11 caused by excessively high doping concentration. This ensures good bonding performance between the ceramic substrate 11 and the piezoelectric material layer 12, and also prevents excessive damage to the surface or interior of the ceramic substrate 110 during the formation of the doped layer 113, thus maintaining the material properties of the ceramic substrate 11. In some embodiments, the warpage of the ceramic substrate 11 with the doped layer 113 is 10–14 micrometers, which is slightly higher than the warpage of conventional ceramic substrates, but it significantly improves the Q-value while ensuring better performance during subsequent bonding.

[0044] Reference Figure 7 In another embodiment of the present invention, the electronic device 100 (composite piezoelectric substrate 10) further includes an intermediate layer 13, which is located between the piezoelectric material layer 12 and the ceramic substrate 11. The sound velocity in the intermediate layer 13 is lower than that in the piezoelectric material layer 12. That is, the sound velocity of the volume wave in the intermediate layer 13 is lower than that of the volume wave propagating in the piezoelectric material layer 12. In this embodiment, by setting a low-velocity intermediate layer 13, the sound velocity of the elastic wave can be reduced, and the energy of the elastic wave can be concentrated in the low-velocity medium (i.e., the intermediate layer 13), thereby reducing losses and improving the Q value.

[0045] The intermediate layer 13 is made of silicon oxide, silicon oxynitride, tantalum oxide, or any one of these materials as the main component. In some embodiments, the intermediate layer is made of silicon oxide, and the piezoelectric material layer 12 is made of lithium tantalate. Lithium tantalate has a negative temperature coefficient of elasticity, while silicon dioxide has a positive temperature coefficient of elasticity, thereby reducing the absolute value of the TCF (temperature drift coefficient) of the elastic wave device. Furthermore, the inherent acoustic impedance of silicon oxide is lower than that of lithium tantalate, thus increasing the electromechanical coupling coefficient of the electronic components.

[0046] In some embodiments, the thickness of the intermediate layer 13 is greater than or equal to 0.5λ, where λ is the wavelength of the elastic wave determined by the electrode period of the IDT electrode 21. Specifically, the thickness of the intermediate layer 13 can be 0.6 to 0.8λ. In some embodiments, the thickness of the piezoelectric material layer 12 is less than or equal to 2λ. Specifically, the thickness of the piezoelectric material layer 12 can be less than 1λ. In one specific embodiment, λ is 2.25 micrometers, the piezoelectric material layer 12 is 0.1λ to 1λ, and the thickness of the intermediate layer 13 is 0.6λ.

[0047] The electronic device 100 provided in this embodiment can be packaged in CSP (Chip Scale Package) or WLP (Wafer Level Package).

[0048] For example, refer to Figure 8 This is a schematic diagram of an electronic device 100 using CSP packaging. The electronic device 100 includes components (including a composite piezoelectric substrate 10 and electrodes 20), a packaging substrate 30, a first sealing structure 41, and a first external terminal electrode 53. The packaging substrate 30 is disposed opposite to the surface of the electrode 20 of the component (i.e., the third surface 121 of the piezoelectric material layer 12), and a gap 60 is formed between the packaging substrate 30 and the third surface 121. The first sealing structure 41 is disposed on the side of the packaging substrate 30 facing the component, covering the side of the component and the side facing away from the packaging substrate 30, to seal the gap 60 and seal the component. The electrode 20 includes electrode pads 22 electrically connected to IDT electrodes 21. The electrode pads 22 are electrically connected to a first conductive portion 52 in the wiring pattern on the packaging substrate 30 via bumps 51. The first conductive portion 52 is electrically connected to the first external terminal electrode 53 on the side of the packaging substrate 30 facing away from the component, enabling electrical connection between the electronic device 100 and external devices through the first external terminal electrode 53.

[0049] The materials of the packaging substrate 30 and the first sealing structure 41 can refer to the substrate materials and sealing materials commonly used in existing CSP packaging. The electrode pads 22, bumps 51, first conductive parts 52 and first external terminal electrodes 53 are all made of materials with good conductivity. This embodiment is not limited to the above examples.

[0050] Reference Figure 9 This is a schematic diagram of an electronic device 100 using CSP packaging. The electronic device 100 includes components (including a composite piezoelectric substrate 10 and electrodes 20), a cover 70, a second sealing structure 42, and a second external terminal electrode. The cover 70 is disposed opposite to the side of the component where the electrodes 20 are located (i.e., the third surface 121 of the piezoelectric material layer 12), and a gap 60 is formed between the cover 70 and the third surface 121. The electrodes 20 include electrode pads 22 electrically connected to IDT electrodes 21. The area on the third surface 121 where the IDT electrodes 21 are located is called the effective area. The second sealing structure 42 is disposed between the cover 70 and the component, and surrounds this effective area. The second sealing structure 42 surrounds the electrode pads 22 to achieve a seal for the component. The second external terminal electrode 55, disposed on the surface of the cover 70 facing away from the component, is connected to the electrode pads 22 through a second conductive portion 54 penetrating the cover 70 and the second sealing structure 42, so that the electronic device 100 can be electrically connected to external devices through the second external terminal electrode 55.

[0051] The materials of the cover 70 and the second sealing structure 42 can refer to the cover materials and sealing materials used in existing WLP packaging. The electrode pads 22, the second conductive part 54 and the second external terminal electrode 55 are all made of materials with good conductivity. This embodiment is not limited.

[0052] Reference Figure 10 The invention also provides a module 1000, including a wiring substrate 700, a plurality of external connection terminals 701, an integrated circuit component 600, an electronic device 100 (including a composite piezoelectric substrate 10), an inductor 400, and a sealing portion 500. The plurality of external connection terminals 701 are formed on one surface of the wiring substrate 700 and are mounted on a pre-defined motherboard of a mobile communication terminal. The integrated circuit component 600 (which may be referred to as an IC) is mounted inside the wiring substrate 700. The integrated circuit component 600 includes a switching circuit and a noise amplifier. The electronic device 100 is mounted on the main surface of the wiring substrate 700. The inductor 400 is used for impedance matching; for example, the inductor 400 is an integrated passive device (IPD). The sealing portion 500 is used to seal the plurality of electronic components, including the electronic device 100, onto the wiring substrate 700.

[0053] The module 1000 provided in this embodiment includes an electronic device 100, which includes a ceramic substrate 11 and has the same effect as the ceramic substrate 11, so it will not be described in detail here.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A ceramic substrate, characterized in that, include: A ceramic material matrix has a first surface and a second surface opposite to each other. A doped layer of a predetermined thickness is formed within the ceramic material matrix, extending from the first surface towards the second surface. The doped layer includes a target dopant element doped into the ceramic material matrix, and the doping concentration of the target dopant element within the doped layer is in the range of 1 × 10⁻⁶. 17 ions / cm 3 ~5×10 20 ions / cm 3 .

2. The ceramic substrate as described in claim 1, characterized in that, The Young's modulus of the ceramic substrate is 1.05 to 1.5 times that of the ceramic material matrix.

3. The ceramic substrate as described in claim 1, characterized in that, The target doping element is any one or more of nitrogen, boron, phosphorus, and carbon.

4. The ceramic substrate as described in claim 1, characterized in that, The ceramic material matrix is ​​any one of polycrystalline magnesium aluminum spinel, polycrystalline sapphire, polycrystalline aluminum nitride, polycrystalline magnesium oxide, polycrystalline quartz, and polycrystalline silicon carbide.

5. The ceramic substrate as described in claim 1, characterized in that, The Young's modulus of the ceramic substrate is 294–392 GPa.

6. A composite piezoelectric substrate, characterized in that, The ceramic substrate as described in any one of claims 1 to 5 further includes a piezoelectric material layer disposed on the side of the first surface facing away from the second surface.

7. An electronic device, characterized in that, The composite piezoelectric substrate as described in claim 6 further includes an electrode located on the side of the piezoelectric material layer facing away from the ceramic substrate.

8. The electronic device as claimed in claim 7, characterized in that, The electrode is an IDT electrode, and the preset thickness is 0.025λ to 2λ, where λ is the wavelength of the elastic wave determined by the electrode period of the IDT electrode.

9. The electronic device as claimed in claim 7, characterized in that, It also includes an intermediate layer located between the first surface and the piezoelectric material layer, wherein the sound velocity of the intermediate layer is lower than that of the piezoelectric material layer.

10. The electronic device as claimed in claim 9, characterized in that, The electrode is an IDT electrode, and the thickness of the intermediate layer is greater than or equal to 0.5λ, where λ is the wavelength of the elastic wave determined by the electrode period of the IDT electrode.

11. The electronic device as claimed in claim 7, characterized in that, The electrode is an IDT electrode, and the thickness of the piezoelectric material layer is less than or equal to 2λ, where λ is the wavelength of the elastic wave determined by the electrode period of the IDT electrode.

12. A module, characterized in that, It includes a wiring board, a plurality of external connection terminals, an inductor and a sealing portion, and an electronic device as described in any one of claims 1 to 11.

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