Temperature compensated resonator

Abstract

The present invention provides a temperature-compensated resonator that maintains the overall device temperature at a low level, thereby effectively suppressing frequency drift with temperature and alleviating thermal stress at the interface between the piezoelectric substrate and the temperature compensation material. The temperature-compensated resonator comprises: a piezoelectric substrate; interdigital electrodes formed on the upper surface of the piezoelectric substrate; and a frequency drift suppression layer laminated on the upper surface of the piezoelectric substrate, covering the interdigital electrodes and suppressing frequency drift caused by temperature changes. The frequency drift suppression layer comprises, along the lamination direction, a temperature compensation layer having a positive acoustic velocity temperature coefficient; and a phase change layer that suppresses the temperature rise of the temperature-compensated resonator through thermoinduced phase change properties.

Description

Technical Field

[0001] The present invention relates to a temperature compensated resonator, and in particular to a temperature compensated surface acoustic wave (TC-SAW) filter for a radio frequency front-end filter. Background Art

[0002] For surface acoustic wave (SAW) filters, their operating frequency is very sensitive to temperature and has the characteristic of frequency drifting with the operating temperature. In engineering, the magnitude of frequency drift with temperature is usually measured by the temperature coefficient of frequency (TCF). The smaller the TCF value, the smaller the temperature dependence of the SAW and the more stable the device performance.

[0003] In the prior art, there are two common methods for improving the temperature stability of SAW filters.

[0004] One is to bond a piezoelectric substrate with a high thermal expansion coefficient (TEC) to a substrate with a low TEC (such as sapphire, Si, or spinel) to improve the TEC of the device and thus improve the TCF value, such as Figure 7 shown.

[0005] The second method is to deposit a layer of temperature compensation material (such as SiO2) with a positive temperature coefficient of velocity (TCV) on a piezoelectric substrate made of lithium tantalate (LiTaO3) or lithium niobate (LiNbO3) with a negative temperature coefficient of velocity (TCV) to suppress the frequency drift caused by temperature changes and thus improve the TCF of the device. Figure 8 shown. Summary of the Invention

[0006] Technical problems to be solved by the present invention

[0007] However, the first method mentioned above is typically applied to the bottom of the lithium tantalate (LiTaO3) substrate. In most cases, the device's temperature rise is primarily due to the heating of the fingers of the interdigital transducer (IDT). Therefore, this method cannot effectively suppress the thermal strain on the top surface of the piezoelectric substrate (i.e., the interface between the LiTaO3 substrate and the interdigital electrodes in the figure), and thus has limited effect on improving the TCF value. Furthermore, the electromechanical coupling coefficient under this condition is low, making it difficult to meet high bandwidth requirements.

[0008] In addition, in the case of the second method mentioned above, due to the difference in thermal expansion coefficient, strong stress concentration is easily generated at the interface between the piezoelectric substrate and the temperature compensation material, thereby affecting the performance of the device. In addition, this structure often requires a thicker silicon dioxide covering to reduce the TCF to a lower level, which is not conducive to the miniaturization design of the device.

[0009] The present invention is completed to solve the above-mentioned problems. Its purpose is to provide a temperature-compensated resonator that can maintain the overall temperature of the device at a low level, thereby effectively suppressing the frequency drift with temperature and effectively alleviating the thermal stress level at the interface between the piezoelectric substrate and the temperature compensation material.

[0010] Technical solutions to technical problems

[0011] In order to solve the above technical problems, the temperature-compensated resonator involved in the first aspect of the present invention includes: a piezoelectric substrate; interdigital electrodes, which are formed on the upper surface of the piezoelectric substrate; and a frequency drift suppression layer, which is stacked on the upper surface of the piezoelectric substrate, covers the interdigital electrodes, and suppresses the frequency drift caused by temperature changes. The temperature-compensated resonator is characterized in that the frequency drift suppression layer has, along the stacking direction,: a temperature compensation layer, which has a positive sound velocity temperature coefficient; and a phase change layer, which suppresses the temperature rise of the temperature-compensated resonator through thermoinduced phase change characteristics.

[0012] Furthermore, the temperature-compensated resonator according to the second aspect of the present invention is preferably such that, in the first aspect of the present invention, the temperature compensation layer is disposed on the upper surface of the piezoelectric substrate to cover the interdigital electrodes, and the phase change layer is disposed on the upper surface of the temperature compensation layer.

[0013] Furthermore, in the temperature-compensated resonator according to the third aspect of the present invention, in the second aspect of the present invention, it is preferable that the phase change layer is made of vanadium dioxide.

[0014] In addition, the temperature-compensated resonator involved in the fourth aspect of the present invention is preferably in the second aspect of the present invention, wherein the phase change layer is composed of doped vanadium dioxide, and the doping is composed of one or more elements of tungsten, hafnium, molybdenum, tantalum, niobium, fluorine, and ruthenium, and their concentrations remain consistent.

[0015] Furthermore, in the temperature-compensated resonator according to the fifth aspect of the present invention, in the fourth aspect of the present invention, it is preferable that the doping concentration is less than 4%.

[0016] In addition, the temperature-compensated resonator involved in the sixth aspect of the present invention is preferably in the second aspect of the present invention, wherein the phase change layer is composed of doped vanadium dioxide, and the doping is composed of one or more elements of tungsten, hafnium, molybdenum, tantalum, niobium, fluorine, and ruthenium, and the concentration thereof decreases successively from bottom to top along the stacking direction.

[0017] Furthermore, in the temperature-compensated resonator according to the seventh aspect of the present invention, in the sixth aspect of the present invention, it is preferable that the doping concentration is less than 4%.

[0018] In addition, the temperature-compensated resonator involved in the eighth aspect of the present invention is preferably in the first aspect of the present invention, wherein the frequency drift suppression layer includes a first temperature compensation layer and a second temperature compensation layer, the first temperature compensation layer is arranged on the upper surface of the piezoelectric substrate to cover the interdigitated electrode, and the second temperature compensation layer is arranged on the upper surface of the first temperature compensation layer through the phase change layer.

[0019] Furthermore, the temperature-compensated resonator according to the ninth aspect of the present invention is preferably such that, in the eighth aspect of the present invention, the phase change layer is made of vanadium dioxide.

[0020] In addition, the temperature-compensated resonator involved in the tenth aspect of the present invention is preferably in the eighth aspect of the present invention, wherein the phase change layer is composed of doped vanadium dioxide, and the doping is composed of one or more elements of tungsten, hafnium, molybdenum, tantalum, niobium, fluorine, and ruthenium, and their concentrations remain consistent.

[0021] Furthermore, in the temperature-compensated resonator according to the eleventh aspect of the present invention, in the tenth aspect of the present invention, it is preferable that the doping concentration is less than 4%.

[0022] In addition, the temperature-compensated resonator involved in the twelfth aspect of the present invention is preferably in the eighth aspect of the present invention, wherein the phase change layer is composed of doped vanadium dioxide, and the doping is composed of one or more elements of tungsten, hafnium, molybdenum, tantalum, niobium, fluorine, and ruthenium, and the concentration thereof decreases successively from bottom to top along the stacking direction.

[0023] Furthermore, the temperature-compensated resonator according to the thirteenth aspect of the present invention is preferably such that, in the twelfth aspect of the present invention, the doping concentration is less than 4%.

[0024] In addition, the temperature-compensated resonator involved in the fourteenth aspect of the present invention is preferably in the first aspect of the present invention, wherein the frequency drift suppression layer includes multiple temperature compensation layers and multiple phase change layers, and the multiple temperature compensation layers and the multiple phase change layers are alternately arranged along the stacking direction, and the temperature compensation layer arranged at the bottom of the frequency drift suppression layer is arranged on the upper surface of the piezoelectric substrate to cover the interdigitated electrodes.

[0025] Furthermore, the temperature-compensated resonator according to the fifteenth aspect of the present invention is preferably such that, in the fourteenth aspect of the present invention, the plurality of phase change layers are made of vanadium dioxide.

[0026] In addition, the temperature-compensated resonator involved in the sixteenth aspect of the present invention is preferably in the fourteenth aspect of the present invention, wherein the multiple phase change layers are composed of doped vanadium dioxide, and the doping is composed of one or more elements of tungsten, hafnium, molybdenum, tantalum, niobium, fluorine, and ruthenium, and the concentration of the doping in each phase change layer remains consistent.

[0027] Furthermore, the temperature-compensated resonator according to the seventeenth aspect of the present invention is preferably such that, in the sixteenth aspect of the present invention, the doping concentration is less than 4%.

[0028] In addition, the temperature-compensated resonator involved in the eighteenth aspect of the present invention is preferably in the fourteenth aspect of the present invention, wherein the multiple phase change layers are composed of doped vanadium dioxide, and the doping is composed of one or more elements of tungsten, hafnium, molybdenum, tantalum, niobium, fluorine, and ruthenium, and the concentration of the doping in each phase change layer decreases successively from bottom to top along the stacking direction.

[0029] Furthermore, the temperature-compensated resonator according to the nineteenth aspect of the present invention is preferably such that, in the eighteenth aspect of the present invention, the doping concentration is less than 4%.

[0030] In addition, the temperature-compensated resonator involved in the twentieth aspect of the present invention is preferably in the first to nineteenth aspects of the present invention, and further includes a frequency modulation layer, which is formed on the upper surface of the frequency drift suppression layer to adjust the operating frequency of the temperature-compensated resonator.

[0031] In addition, the temperature-compensated resonator involved in the twenty-first aspect of the present invention is preferably in the first to nineteenth aspects of the present invention, and further includes a stray response suppression layer, which is formed on the upper surface and two side surfaces of the interdigitated electrode to suppress the stray response of the temperature-compensated resonator.

[0032] Effects of the Invention

[0033] The temperature-compensated resonator of the present invention can maintain the overall temperature of the device at a low level, thereby effectively suppressing the frequency drift with temperature and effectively alleviating the thermal stress level at the interface between the piezoelectric substrate and the temperature compensation material. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a diagram showing the structure of a temperature-compensated resonator according to the first embodiment of the present invention.

[0035] Figure 2 Yes Figure 1A structural diagram of an example of the doping concentration of the phase change layer.

[0036] Figure 3 FIG. 1 is a diagram showing the structure of a temperature-compensated resonator according to a second embodiment of the present invention.

[0037] Figure 4 FIG. 1 is a diagram showing the structure of a temperature-compensated resonator according to a third embodiment of the present invention.

[0038] Figure 5 FIG. 1 is a diagram showing the structure of a temperature-compensated resonator according to a fourth embodiment of the present invention.

[0039] Figure 6 Yes Figure 5 A top view of the structure of the spurious response suppression layer in FIG.

[0040] Figure 7 This is a structural diagram showing a conventional method for improving the TCF value.

[0041] Figure 8 This is a structural diagram showing the second conventional TCF value improvement method. DETAILED DESCRIPTION

[0042] Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

[0043] Implementation Method 1

[0044] Figure 1 1 is a diagram showing the structure of the temperature-compensated resonator 100 according to the first embodiment.

[0045] The temperature compensated resonator 100 is, for example, a TC-SAW used in a radio frequency front-end filter, such as Figure 1 As shown, it includes a piezoelectric substrate 1, interdigital electrodes 2, a temperature compensation layer 3 and a phase change layer 4, wherein the temperature compensation layer 3 and the phase change layer 4 constitute a frequency drift suppression layer.

[0046] The piezoelectric substrate 1 is composed of a material such as lithium tantalate (LiTaO3) or lithium niobate (LiNbO3). Interdigital electrodes 2, composed of a conductive material such as copper, are formed on the upper surface of the piezoelectric substrate 1. A frequency drift suppression layer is laminated on the upper surface of the piezoelectric substrate 1 and covers the interdigital electrodes 2. The temperature-compensated resonator 100 of the present invention utilizes this frequency drift suppression layer to suppress frequency drift caused by temperature changes, i.e., frequency drift that occurs with increasing operating temperature. Temperature changes can be caused by, but are not limited to, heat generated by the interdigital electrodes 2 during operation, heat generated by other components of the temperature-compensated resonator 100 during operation, or changes in the external temperature of the temperature-compensated resonator 100.

[0047] like Figure 1 As shown, the frequency drift suppression layer has a temperature compensation layer 3 and a phase change layer 4 along the stacking direction. Considering that the phase change layer 4 described later is composed of a vanadium dioxide / doped vanadium dioxide thin film, and the vanadium dioxide / doped vanadium dioxide thin film is easy to grow on substrates such as ordinary glass, quartz glass, sapphire, and mica, and in order to better achieve temperature compensation, the temperature compensation layer 3 is preferably composed of a material with a positive acoustic temperature coefficient such as silicon dioxide (SiO2). Through the positive acoustic temperature coefficient of the temperature compensation layer 3, the frequency drift caused by temperature changes of the piezoelectric substrate composed of materials with a negative acoustic temperature coefficient such as lithium tantalate (LiTaO3) and lithium niobate (LiNbO3) can be suppressed, thereby improving the TCF of the device. In this embodiment, the temperature compensation layer 3 is arranged on the upper surface of the piezoelectric substrate 1 to cover the interdigital electrodes 2.

[0048] However, as described above, due to the difference in thermal expansion coefficients between the piezoelectric substrate 1 and the temperature compensation layer 3 , significant stress concentration is likely to occur at the interface between the piezoelectric substrate 1 and the temperature compensation layer 3 , thereby affecting the stability and safety of the device.

[0049] In order to solve the above problems, Figure 1 As shown, the temperature-compensated resonator 100 of this embodiment further includes a phase change layer 4 covering the upper surface of the temperature compensation layer 3. This phase change layer 4 suppresses the temperature rise of the temperature-compensated resonator 100 through its thermoinduced phase change properties. The so-called thermoinduced phase change property is a process technology that causes the temperature of the phase change material to rise due to heat absorption, and then the material undergoes a structural transformation after exceeding the phase transition temperature. By adding the phase change layer 4 with thermoinduced phase change properties, the heat generated by the interdigital electrodes 2 and conducted to the phase change layer 4 through the temperature compensation layer 3 is effectively absorbed, thereby effectively reducing the temperature, thereby suppressing temperature drift and alleviating thermal stress levels.

[0050] As a preferred example of phase change layer 4, vanadium dioxide (VO2) can be used to form phase change layer 4. Vanadium dioxide is a functional material with thermoinduced phase change properties. Its phase transition temperature is close to room temperature, and a metal-insulator transition (reversible) occurs at a phase transition temperature of 68°C. This transition occurs in less than 1 nanosecond, which is an advantage for electronic applications. When the temperature rises to the phase transition temperature, most of the heat is used to cause the vanadium dioxide phase transition, which can effectively mitigate the further increase in system temperature and maintain the temperature within a relatively stable range.

[0051] However, since the phase transition temperature of 68°C may still be too high for the operating temperature of the filter in the mobile phone (-25°C to 85°C), the temperature can be better controlled and the TCF value can be improved by lowering the phase transition temperature of vanadium dioxide. Studies have found that the phase transition temperature of vanadium dioxide (VO2) thin films can be significantly changed by doping. For example, doping with large-sized atoms such as W and Mo can effectively reduce the phase transition temperature, while doping with small-sized atoms such as Al and P can increase the phase transition temperature. Various doped VO2 can be prepared through various known preparation methods, so that the phase transition temperature and performance of VO2 can be appropriately regulated.

[0052] As specific examples of doping elements, to lower the phase transition temperature of VO2, one or more of tungsten, hafnium, molybdenum, tantalum, niobium, fluorine, and ruthenium can be used. By controlling the doping ratio, the phase transition temperature can be controlled within a range of 25°C to 55°C.

[0053] In addition, although VO2 is used as an example of a phase change material in this embodiment, the present invention is not limited thereto. Any low-temperature phase change material with a phase change temperature in the range of -25°C to 80°C, preferably 25°C to 55°C, can be used as the material constituting the phase change layer of the present invention.

[0054] In addition, if the phase change layer 4 itself is conductive or becomes conductive after phase change, the thickness of the temperature compensation layer 3 in contact with the interdigital electrode 2 should be greater than the thickness of the interdigital electrode 2 to prevent the phase change layer 4 itself / the phase change layer 4 after phase change from causing a short circuit in the device.

[0055] In this embodiment, when the phase change layer 4 is a doped vanadium dioxide thin film, the doping concentration can be kept consistent. In order to obtain better thermoinduced phase change characteristics, the doping concentration is preferably less than 4%.

[0056] In addition, the doping concentration of the phase change layer 4 may also be varied. The following describes the variation of the doping concentration.

[0057] Figure 2 Yes Figure 1 FIG. 1 is a structural diagram showing an example of the doping concentration of the phase change layer 4 in FIG. For simplicity of description, only the structure of the phase change layer 4 is shown in the figure, and illustrations of other components of the temperature-compensated resonator 100 are omitted.

[0058] like Figure 2 As shown, the phase change layer 4 is composed of doped vanadium dioxide, wherein the doping concentration decreases from bottom to top along the stacking direction. Specifically, the doping concentration from bottom to top is C1, C2, ..., C n (n is a natural number greater than 2), and C1>C2>…>C nrelationship.

[0059] Take tungsten as the doping and n=2 as an example. When the doping molar ratio of tungsten ions to vanadium ions is a constant, for example, C1=C2=1.8%, the phase transition temperature can be reduced to about 23°C. On the other hand, when the doping molar ratio of tungsten ions to vanadium ions is a non-constant value, for example, C1=1.8% (phase transition temperature of about 23°C) and C2=0.9% (phase transition temperature of about 44°C), the phase transition temperature can be gradually reduced along the stacking direction. The former structure is beneficial for controlling the operating temperature of the device at a lower level, while the latter structure is beneficial for dealing with damage to the device caused by sudden temperature changes from outside the device. It can be appropriately selected according to the application scenario of the device.

[0060] In addition, as an improved structure of this embodiment, Figure 1 As shown, the temperature-compensated resonator 100 may further include a frequency-modulation layer 5, which is formed on the upper surface of the phase change layer 4 to adjust the operating frequency of the temperature-compensated resonator 100. The frequency-modulation layer 5 may be composed of, for example, one or more of silicon nitride, silicon dioxide, aluminum nitride, and silicon carbide. For example, after the temperature-compensated layer 3 and the phase change layer 4 are deposited, the frequency is measured by a probe. When the frequency is too high, a frequency-modulation layer 5 composed of silicon dioxide may be covered on the phase change layer 4 to lower the frequency. On the other hand, when the frequency is too low, a frequency-modulation layer 5 composed of silicon nitride may be covered on the phase change layer 4 to increase the frequency. By configuring the frequency-modulation layer 5, the operating frequency of the resonator can be further adjusted, thereby further improving the overall performance of the temperature-compensated resonator 100.

[0061] According to the structure of the first embodiment, the phase change layer 4 is introduced to maintain the overall temperature of the device at a relatively low level, thereby effectively alleviating the thermal stress level at the device interface and effectively suppressing temperature drift.

[0062] In addition, through the combined effect of the phase change layer 4 and the temperature compensation layer 3 , the TCF value of the device can be further effectively reduced, thereby obtaining a device with better temperature stability.

[0063] Implementation Method 2

[0064] Figure 3 1 is a diagram showing the structure of a temperature-compensated resonator 101 according to the second embodiment.

[0065] and Figure 1 The temperature compensated resonator 100 shown is different. Figure 3 The frequency drift suppression layer of the temperature compensation type resonator 101 shown includes two temperature compensation layers, namely a first temperature compensation layer 3a and a second temperature compensation layer 3b. Figure 3As shown, the first temperature compensation layer 3a is disposed on the upper surface of the piezoelectric substrate 1, covering the interdigital electrodes 2. The second temperature compensation layer 3b is disposed on the upper surface of the first temperature compensation layer 3a via the phase change layer 4. The remaining structure is the same as that of the first embodiment and is not described here.

[0066] According to the above-described structure of the second embodiment, the temperature compensation effect can be further enhanced, and the reliability of the temperature-compensated resonator can be further improved.

[0067] Implementation 3

[0068] Figure 4 1 is a diagram showing the structure of a temperature-compensated resonator 102 according to the third embodiment.

[0069] The difference between the temperature-compensated resonator 100 of the first embodiment and the temperature-compensated resonator 101 of the second embodiment is that the frequency drift suppression layer of the temperature-compensated resonator 102 of the third embodiment includes a plurality of temperature compensation layers 3a, 3b, ..., 3n (n is a natural number greater than or equal to 2) and a plurality of phase change layers 4a, 4b, ..., 4n (n is a natural number greater than or equal to 2). Figure 4 As shown, multiple temperature compensation layers 3a, 3b, ..., 3n and multiple phase change layers 4a, 4b, ..., 4n are alternately arranged along the stacking direction. Temperature compensation layer 3a is located at the bottom of the frequency drift suppression layer. This temperature compensation layer 3a is located on the top surface of piezoelectric substrate 1 and covers interdigital electrodes 2.

[0070] According to the above-described structure of the third embodiment, the temperature compensation effect can be further enhanced, and the reliability of the temperature-compensated resonator can be further improved.

[0071] In addition, when the phase change layers 4a, 4b, ..., 4n are composed of doped vanadium dioxide, the doping concentration of each phase change layer can be consistent or non-constant. Figure 4 As shown, if the doping concentrations of the phase change layers 4a, 4b, ..., 4n are C1, C2, ..., C n , then we can make C1=C2=……=C n In addition, the doping concentration of each phase change layer can also be made to decrease from bottom to top along the stacking direction, that is, C1>C2>...>C n .

[0072] Take tantalum as the dopant and n=3 as an example. The doping molar ratio of tantalum ions to vanadium ions can be a constant value, for example, when C1=C2=C3=3%, the phase transition temperature can be reduced to about 37°C. On the other hand, when the doping molar ratio of tantalum ions to vanadium ions is a non-constant value, for example, when C1=3% (phase transition temperature of about 37°C), C2=1.5% (phase transition temperature of about 42°C), and C3=1% (phase transition temperature of about 52°C), the phase transition temperature can be gradually reduced along the stacking direction. The former structure is beneficial for controlling the operating temperature of the device at a lower level, while the latter structure is beneficial for dealing with damage to the device caused by sudden temperature changes outside the device. The selection can be made appropriately according to the application scenario of the device.

[0073] In addition, in order to obtain better thermoinduced phase change characteristics, it is preferred that the doping concentration is less than 4%.

[0074] Implementation 4

[0075] Figure 5 1 is a diagram showing the structure of the temperature-compensated resonator 103 according to the fourth embodiment. Figure 6 Yes Figure 5 A top view of the structure of the spurious response suppression layer 6 in FIG.

[0076] The difference between the temperature-compensated resonators 100 to 102 in the first to third embodiments is that the temperature-compensated resonator 103 in the fourth embodiment further includes a spurious response suppression layer 6 formed on the upper surface and both side surfaces of the interdigital electrode 2. Specifically, Figure 5 and Figure 6 As shown, each interdigital electrode 2 has a first end electrically connected to one of two upper and lower bus bars 7, and a second end opposite the first end, with a gap separating the second end from the opposing bus bar 7. A spurious response suppression layer 6 is formed at the second end of each interdigital electrode 2 and at a location opposing the second end of an adjacent interdigital electrode 2. The spurious response suppression layer 6 covers the top surface and both side surfaces of the interdigital electrodes 2. Specifically, the temperature-compensated resonator 103 of this fourth embodiment employs the so-called piston method.

[0077] The thickness of the spurious response suppression layer 6 should not be too thick to avoid the spurious response suppression layer 6 penetrating the temperature compensation layer 3 a and contacting the phase change layer 4 to cause a short circuit, or contacting the adjacent interdigital electrodes 2 to cause a short circuit.

[0078] According to the above-described structure of the fourth embodiment, the spurious response of the temperature-compensated resonator can be further suppressed, and the reliability of the temperature-compensated resonator can be further improved.

[0079] While various embodiments of the present invention have been described above, it should be understood that all aspects of the embodiments disclosed herein are merely illustrative and non-restrictive. The scope of the present invention is indicated by the claims, not by the embodiments described above, and includes all modifications and variations within the meaning and scope equivalent to the claims.

[0080] Industrial applicability

[0081] The temperature-compensated resonator of the present invention is useful for temperature-compensated surface acoustic wave filters of radio frequency front-end filters of wireless communication devices such as mobile phones and base stations.

[0082] Description of labels

[0083] 1Piezoelectric substrate

[0084] 2-digit electrode

[0085] 3. 3a, 3b, 3n temperature compensation layers

[0086] 4, 4a, 4b, 4n phase change layers

[0087] 5 FM layers

[0088] 6 Spurious response suppression layer

[0089] 7 busbars

[0090] 100, 101, 102, 103 temperature-compensated resonators

Claims

1. A temperature-compensated resonator, comprising: Piezoelectric substrate; an interdigital electrode formed on the upper surface of the piezoelectric substrate; and a frequency drift suppression layer, which is stacked on the upper surface of the piezoelectric substrate, covers the interdigital electrodes, and suppresses the frequency drift caused by temperature changes. The temperature-compensated resonator is characterized in that: The frequency drift suppression layer has the following characteristics along the stacking direction: a temperature compensation layer having a positive temperature coefficient of sound velocity; as well as A phase change layer is not in contact with the interdigital electrodes and suppresses a temperature increase of the temperature-compensated resonator by utilizing a thermo-induced phase change characteristic.

2. The temperature-compensated resonator according to claim 1, wherein The temperature compensation layer is disposed on the upper surface of the piezoelectric substrate and covers the interdigital electrodes. The phase change layer is configured on the upper surface of the temperature compensation layer.

3. The temperature-compensated resonator according to claim 2, wherein: The phase change layer is made of vanadium dioxide.

4. The temperature-compensated resonator according to claim 2, wherein: The phase change layer is composed of doped vanadium dioxide, The doping is composed of one or more elements selected from tungsten, hafnium, molybdenum, tantalum, niobium, fluorine and ruthenium, and the concentrations thereof are kept consistent.

5. The temperature-compensated resonator according to claim 4, wherein: The doping concentration is less than 4%.

6. The temperature-compensated resonator according to claim 2, wherein: The phase change layer is composed of doped vanadium dioxide, The doping is composed of one or more elements selected from tungsten, hafnium, molybdenum, tantalum, niobium, fluorine and ruthenium, and the concentration of the doping decreases from bottom to top along the stacking direction.

7. The temperature-compensated resonator according to claim 6, wherein: The doping concentration is less than 4%.

8. The temperature-compensated resonator according to claim 1, wherein The frequency drift suppression layer includes a first temperature compensation layer and a second temperature compensation layer, The first temperature compensation layer is disposed on the upper surface of the piezoelectric substrate and covers the interdigital electrodes. The second temperature compensation layer is disposed on an upper surface of the first temperature compensation layer via the phase change layer.

9. The temperature-compensated resonator according to claim 8, wherein: The phase change layer is made of vanadium dioxide.

10. The temperature-compensated resonator according to claim 8, wherein The phase change layer is composed of doped vanadium dioxide, The doping is composed of one or more elements selected from tungsten, hafnium, molybdenum, tantalum, niobium, fluorine and ruthenium, and the concentrations thereof are kept consistent.

11. The temperature-compensated resonator according to claim 10, wherein: The doping concentration is less than 4%.

12. The temperature-compensated resonator according to claim 8, wherein The phase change layer is composed of doped vanadium dioxide, The doping is composed of one or more elements selected from tungsten, hafnium, molybdenum, tantalum, niobium, fluorine and ruthenium, and the concentration of the doping decreases from bottom to top along the stacking direction.

13. The temperature-compensated resonator according to claim 12, wherein: The doping concentration is less than 4%.

14. The temperature-compensated resonator according to claim 1, wherein The frequency drift suppression layer includes multiple temperature compensation layers and multiple phase change layers. The plurality of temperature compensation layers and the plurality of phase change layers are alternately arranged along a stacking direction. The temperature compensation layer disposed at the bottom of the frequency drift suppression layer is disposed on the upper surface of the piezoelectric substrate and covers the interdigital electrodes.

15. The temperature-compensated resonator according to claim 14, wherein The plurality of phase change layers are made of vanadium dioxide.

16. The temperature-compensated resonator according to claim 14, wherein: The multiple phase change layers are composed of doped vanadium dioxide, The doping is composed of one or more elements selected from tungsten, hafnium, molybdenum, tantalum, niobium, fluorine and ruthenium. The doping concentration of each phase change layer remains consistent.

17. The temperature-compensated resonator according to claim 16, wherein: The doping concentration is less than 4%.

18. The temperature-compensated resonator according to claim 14, wherein The multiple phase change layers are composed of doped vanadium dioxide, The doping is composed of one or more elements selected from tungsten, hafnium, molybdenum, tantalum, niobium, fluorine and ruthenium. The doping concentration of each phase change layer decreases from bottom to top along the stacking direction.

19. The temperature-compensated resonator according to claim 18, wherein The doping concentration is less than 4%.

20. The temperature-compensated resonator according to any one of claims 1 to 19, wherein: The device further comprises a frequency modulation layer, which is formed on the upper surface of the frequency drift suppression layer and is used to adjust the operating frequency of the temperature compensation resonator.

21. The temperature-compensated resonator according to any one of claims 1 to 19, wherein: The invention also includes a stray response suppression layer, which is formed on the upper surface and two side surfaces of the interdigital electrode to suppress the stray response of the temperature compensation resonator.

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