Self-temperature-controlled bulk acoustic wave resonator, filter and preparation method

Abstract

The application provides a self-temperature-control bulk acoustic resonator, filter and preparation method, and relates to the technical field of bulk acoustic resonators. The self-temperature-control bulk acoustic resonator comprises a substrate, a support layer, a bottom electrode, a piezoelectric layer and a top electrode which are stacked in sequence, a cavity is arranged between the substrate and the support layer, a light starting layer and a light refrigeration layer are stacked in sequence on the top electrode, the light starting layer is used for absorbing heat generated by the resonator and exciting low-energy fluorescence when a critical temperature is reached, the light refrigeration layer can convert high-energy photons under the drive of the low-energy fluorescence, and the light starting layer and the light refrigeration layer are matched to convert heat energy into light energy for consumption. The self-temperature-control bulk acoustic resonator solves the problem that heat control of the resonator is not ideal in the prior art, the temperature increases too fast under high frequency, and the resonator is prone to failure, achieves stable control of the heat of the device under high frequency and high power capacity, and is beneficial to guarantee long-term stable operation of the device and greatly improve the power capacity of the bulk acoustic resonator and the filter.

Description

Technical Field

[0001] The present invention relates to the technical field of bulk acoustic wave resonators, and in particular to a self-temperature-controlled bulk acoustic wave resonator, a filter and a preparation method thereof. Background Art

[0002] The development of artificial intelligence (AI) has placed higher demands on communications technology, such as the urgent need for low-latency, high-information communication methods. This has greatly promoted the development of high-frequency communication technologies with fast transmission speeds and large data bandwidths. RF filters are one of the core components in high-frequency communications, and their operating frequency is primarily determined by the operating frequency band of the resonator. Therefore, the development of high-frequency bulk acoustic wave resonators is of great significance to the development of high-frequency communication technologies.

[0003] However, defects in piezoelectric films lead to acoustic wave losses, which in turn generate significant heat. This can cause the device's resonant frequency to drift and even lead to structural burnout and failure. Furthermore, as the operating frequency increases, the rising acoustic wave frequency causes increased heating in the resonator, resulting in low power handling at high frequencies. Therefore, developing temperature and heat control technologies to increase the power handling of BAW resonators is crucial for achieving stable high-frequency device applications.

[0004] The current mainstream approach focuses on improving device thermal conductivity, such as by changing the device structure or introducing a thermally conductive layer. However, this approach is not ideal for controlling the thermal conductivity of the resonator. At high frequencies, the temperature rises too quickly, making it prone to failure.

[0005] There is currently no effective technical solution to the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a self-temperature-controlled bulk acoustic wave resonator, a filter and a preparation method, which solves the problems of the prior art in that the heat control of the resonator is not ideal, the temperature rises too quickly at high frequencies, and it is easy to fail. The invention achieves the effect of stably controlling the heat of the device at high frequencies and high power capacity, which is beneficial to ensure the long-term stable operation of the device while significantly improving the power capacity of the bulk acoustic wave resonator and filter.

[0007] In a first aspect, the present invention provides a self-temperature-controlled bulk acoustic wave resonator, comprising a substrate, a supporting layer, a bottom electrode, a piezoelectric layer and a top electrode stacked in sequence, a cavity being provided between the substrate and the supporting layer, and a light-starting layer and a light-cooling layer being stacked in sequence on the top electrode, wherein the light-starting layer is used to absorb heat generated by the resonator and stimulate low-energy fluorescence when a critical temperature is reached; the light-cooling layer can convert high-energy photons under the drive of the low-energy fluorescence; the light-starting layer and the light-cooling layer cooperate to convert thermal energy into light energy for consumption.

[0008] The self-temperature-controlled bulk acoustic wave resonator provided by the present invention realizes automatic temperature control based on the optical starting layer and the optical cooling layer, greatly improving the power capacity of the bulk acoustic wave resonator and the filter, and effectively solving the problem of device failure caused by severe heating of the bulk acoustic wave resonator and the filter at high frequency and high power, which is conducive to ensuring the long-term stable operation of the device.

[0009] Furthermore, the light-activated layer is made of thermoluminescent material.

[0010] Using thermoluminescent materials as the light-starting layer can achieve self-controlled regulation of the resonator temperature and improve the power capacity and stability of the device under high-frequency operation.

[0011] Furthermore, the thermoluminescent material is any one of halides, sulfates, sulfides, binary oxides or ternary oxides that emit light when heated.

[0012] The limitation of material types makes it easier to find thermoluminescent materials that meet the performance requirements in practical applications and simplifies the material screening and preparation process.

[0013] Furthermore, the optical cooling layer is made of photoluminescent material.

[0014] Furthermore, the photoluminescent material is a halide perovskite or ytterbium-doped fluoride.

[0015] By selecting suitable photoluminescent materials, the energy conversion efficiency can be optimized, thereby improving the cooling effect of the optical cooling layer.

[0016] Furthermore, the bottom electrode and the top electrode are both made of any one or more materials selected from the group consisting of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf.

[0017] Furthermore, the piezoelectric layer is made of AlN, 、 、 Made of any material.

[0018] Furthermore, the substrate is made of any one of Si, sapphire, and SiC; the support layer is made of , SiC, or any one or more materials.

[0019] In a second aspect, the present invention provides a filter comprising the self-temperature-controlled bulk acoustic wave resonator described above.

[0020] In a third aspect, the present invention provides a method for preparing the self-temperature-controlled bulk acoustic wave resonator, comprising the following steps:

[0021] S1. After forming a groove on the upper surface of the substrate, a sacrificial layer is grown on the groove;

[0022] S2. A support layer, a bottom electrode, a piezoelectric layer and a top electrode covering the groove are sequentially formed on the upper surface of the substrate;

[0023] S3. Spin-coating a light-activated layer on the top electrode;

[0024] S4. After the optical activation layer is dried, a light refrigeration layer is spin-coated on the optical activation layer;

[0025] S5. releasing the sacrificial layer to form a cavity between the substrate and the supporting layer, thereby manufacturing the self-temperature-controlled bulk acoustic wave resonator.

[0026] As can be seen from the above, the self-temperature-controlled bulk acoustic wave resonator provided by the present invention uses thermoluminescent materials to excite low-energy fluorescence to drive the optical cooling layer to convert high-energy photons, thereby rapidly consuming the heat of the resonator. When the heat is lower than the critical temperature of the luminescent material, it no longer emits light to drive the optical cooling layer to work, achieving the purpose of automatically regulating the resonator temperature, realizing long-term stable operation of the device at high frequency and high power capacity, and greatly improving the stability and power capacity of the device.

[0027] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the embodiments of the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic structural diagram of a self-temperature-controlled bulk acoustic wave resonator provided by an embodiment of the present invention.

[0029] Figure 2 A flow chart for preparing a self-temperature-controlled bulk acoustic wave resonator provided in an embodiment of the present invention.

[0030] Figure 3 A flow chart of the preparation method provided in an embodiment of the present invention.

[0031] Description of labels:

[0032] 100, substrate; 200, support layer; 300, bottom electrode; 400, piezoelectric layer; 500, top electrode; 600, cavity; 700, optical activation layer; 800, optical cooling layer. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0035] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections, or mutual communication; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0037] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0039] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish descriptions and are not to be understood as indicating or implying relative importance.

[0040] Reference Attachment Figure 1 The present invention provides a self-temperature-controlled bulk acoustic wave resonator, comprising a substrate 100, a supporting layer 200, a bottom electrode 300, a piezoelectric layer 400, and a top electrode 500 stacked in sequence. A cavity 600 is provided between the substrate 100 and the supporting layer 200. A light-starting layer 700 and a light-cooling layer 800 are stacked in sequence on the top electrode 500. The light-starting layer 700 is used to absorb heat generated by the resonator and stimulate low-energy fluorescence when the critical temperature is reached; the light-cooling layer 800 can convert high-energy photons under the drive of the low-energy fluorescence; the light-starting layer 700 and the light-cooling layer 800 cooperate to convert thermal energy into light energy for consumption.

[0041] In the structure of a BAW resonator, a substrate serves as the device's support structure. A supporting layer is fabricated on top of the substrate to further support the functional thin film layers above. A cavity is positioned between the substrate and the supporting layer to achieve acoustic isolation and energy concentration for the BAW resonator. A bottom electrode, piezoelectric layer, and top electrode are fabricated sequentially on the supporting layer, forming the core structure of the BAW resonator. The piezoelectric layer is the key functional layer for converting electrical and acoustic signals, while the bottom and top electrodes are used to apply the driving voltage. A photoactivation layer and a photocooling layer are fabricated on top of the top electrode to form a stacked structure, enabling temperature control of the resonator. One possible implementation of the photoactivation layer is made of a thermoluminescent material. After absorbing heat, this material spontaneously emits fluorescence when the temperature reaches a certain critical value. Thermoluminescent materials can include halides, sulfates, sulfides, binary oxides, and ternary oxides that emit light when exposed to heat. Another possible implementation of the photocooling layer is made of a photoluminescent material. This material can emit higher-energy photons after absorbing light of a specific wavelength, achieving a photocooling effect. Photoluminescent materials can include halide perovskites, ytterbium-doped fluorides, etc. The bottom electrode and the top electrode can be made of any one or more materials selected from gold, silver, ruthenium, tungsten, molybdenum, iridium, aluminum, platinum, niobium, and hafnium to meet the requirements of conductivity and process compatibility. The piezoelectric layer can be made of aluminum nitride, 、 、 The substrate can be made of any of silicon, sapphire, and silicon carbide, and the support layer can be made of any one or more of silicon nitride and silicon carbide to meet mechanical strength and process requirements.

[0042] Specifically, when a BAW resonator operates, defects in the piezoelectric film cause acoustic wave loss, generating heat. When this heat is absorbed by the optical activation layer on the top electrode and the resonator temperature rises to the critical temperature of the optical activation layer, the layer is thermally excited and emits low-energy fluorescence. This low-energy fluorescence is then absorbed by the optical cooling layer above it. After absorbing the low-energy fluorescence, the optical cooling layer undergoes a photon conversion process, converting the low-energy fluorescence into high-energy photons and emitting them. Through the synergistic effect of the optical activation layer and the optical cooling layer, the heat energy generated within the resonator is converted into light energy and dissipated, reducing the device temperature. Furthermore, when the heat falls below the critical temperature of the optical activation layer, the optical cooling layer no longer emits light, thus achieving self-temperature control of the BAW resonator. This self-temperature control mechanism eliminates the need for an external control system and relies entirely on the material's inherent photophysical properties to achieve temperature regulation, which improves the resonator's stability and power handling at high frequencies. BAW resonators employing this technology can effectively address the frequency drift and reduced power handling caused by heat during high-frequency operation, enhancing the device's performance in high-frequency communications applications.

[0043] In some embodiments, the light-activated layer 700 is made of a thermoluminescent material.

[0044] Thermoluminescent materials are chosen to specify the materials used in the optical start layer. The characteristic of thermoluminescent materials is that they emit light when heated. When the resonator operates, heat is generated, and the thermoluminescent material is used to absorb this heat. When the temperature rises to the excitation temperature of the thermoluminescent material, the material begins to emit low-energy fluorescence. This fluorescence serves as the excitation light source for the optical cooling layer, driving it to convert low-energy photons into high-energy photons, achieving a cooling effect and lowering the operating temperature of the resonator. Therefore, the use of thermoluminescent materials ensures that the optical start layer can effectively respond to the heat generated by the resonator and begin to emit light when the temperature reaches a certain level. This material can convert thermal energy into light energy, providing a driving light source for the subsequent optical cooling layer, thereby achieving thermal energy consumption and device temperature control.

[0045] Specifically, when the bulk acoustic wave resonator is operating, the piezoelectric layer generates heat due to acoustic wave losses. If the optical start layer is made of a thermoluminescent material, this layer can be directly attached to the top electrode to quickly and efficiently absorb the heat generated by the resonator. When the heat generated by the resonator causes the temperature of the optical start layer to rise to the excitation temperature of the thermoluminescent material, the thermoluminescent material begins to absorb thermal energy and release low-energy fluorescence. This low-energy fluorescence then irradiates the optical cooling layer, driving the optical cooling layer to operate and convert low-energy photons into high-energy photons. Through the synergistic effect of the optical start layer and the optical cooling layer, the thermal energy generated by the resonator is converted into light energy and consumed, thereby reducing the operating temperature of the resonator and preventing device performance degradation and failure. Using a thermoluminescent material as the optical start layer can achieve self-controlled regulation of the resonator temperature, improving the power capacity and stability of the device under high-frequency operation.

[0046] In certain embodiments, the thermoluminescent material is any one of a halide, sulfate, sulfide, binary oxide, or ternary oxide that emits light upon exposure to heat.

[0047] Halides are compounds formed by metals and halogens, such as sodium chloride and potassium iodide. Sulfates are compounds containing sulfate ions, such as calcium sulfate and barium sulfate. Sulfides are compounds formed by metals and sulfur, such as zinc sulfide and cadmium sulfide. Binary oxides are oxides containing two elements, such as silicon dioxide and zinc oxide. Ternary oxides are oxides containing three elements, such as yttrium aluminum garnet and barium titanate. These materials share a common characteristic: within a specific temperature range, as the temperature rises, electrons within the material are thermally excited to high energy levels. When these high-energy electrons transition back to lower energy levels, they release photons, generating luminescence. By limiting the photo-start layer to these specific material types, it is possible to more precisely select materials with excellent thermoluminescent properties. This allows the photo-start layer to more effectively absorb the heat generated by the resonator and, when it reaches a certain temperature, stimulate low-energy fluorescence, providing the driving force for the subsequent photo-cooling process. The limitation of material types makes it easier to find thermoluminescent materials that meet the performance requirements in practical applications and simplifies the material screening and preparation process.

[0048] In some specific embodiments, the light start layer can be made of zinc sulfide material. Zinc sulfide is a typical sulfide thermoluminescent material. When the temperature rises, zinc sulfide can absorb thermal energy and emit fluorescence in the visible light band. For example, when the operating temperature of the resonator rises to 80 degrees Celsius, the zinc sulfide light start layer begins to absorb the heat generated by the resonator, and when the temperature reaches 100 degrees Celsius, the zinc sulfide material begins to excite green fluorescence. The thermal luminescence characteristics of the zinc sulfide material match the operating temperature range of the bulk acoustic wave resonator, and can effectively convert the thermal energy generated by the resonator into light energy, thereby reducing the operating temperature of the resonator and improving the power capacity and stability of the device. As a mature thermoluminescent material, zinc sulfide material has the advantages of low cost and easy preparation, which is conducive to reducing the manufacturing cost of self-controlled temperature bulk acoustic wave resonators and promoting the commercial application of this technology.

[0049] In some embodiments, the optical cooling layer 800 is made of a photoluminescent material.

[0050] Photoluminescent materials can achieve wavelength conversion. The optical cooling layer is designed to absorb the fluorescence emitted by the optical start layer and convert it into photons. This energy conversion process removes heat from the resonator, thereby achieving a cooling effect. The use of photoluminescent materials allows for efficient conversion of thermal energy into light energy, thereby enhancing the cooling effect of the optical cooling layer. Specifically, the selection of photoluminescent materials can be optimized based on the emission spectrum of the optical start layer to ensure that the optical cooling layer can effectively absorb the fluorescence emitted by the optical start layer. The optical cooling layer can be prepared as a thin film structure and deposited on the optical start layer to maximize the contact area with the fluorescence. When the resonator is operating, the vibration of the piezoelectric layer generates heat, which is absorbed by the optical start layer and converted into low-energy fluorescence. The low-energy fluorescence is then absorbed by the optical cooling layer. The photoluminescent material in the optical cooling layer converts these low-energy fluorescence photons into high-energy photons and emits them. Because the energy of the emitted photons is higher than the energy of the absorbed photons, the energy difference is derived from the heat energy in the resonator, thus achieving cooling of the resonator.

[0051] Specifically, the optical cooling layer uses photoluminescent materials to absorb low-energy fluorescence from the optical start layer and convert these low-energy photons into high-energy photons. This energy conversion process effectively converts the thermal energy inside the resonator into light energy and dissipates it, thereby cooling the resonator. By selecting suitable photoluminescent materials, the energy conversion efficiency can be optimized, thereby improving the cooling effect of the optical cooling layer. For example, when the resonator temperature rises and causes the optical start layer to emit fluorescence of a specific wavelength, the photoluminescent material in the optical cooling layer absorbs this fluorescence and emits photons with shorter wavelengths and higher energy through the photoluminescence process. This process continues, continuously consuming the thermal energy generated by the resonator in the form of light, maintaining the resonator at a lower operating temperature, and thereby improving the performance and stability of the device.

[0052] In certain embodiments, the photoluminescent material is a halide perovskite or an ytterbium-doped fluoride.

[0053] The optical cooling layer is limited to halide perovskites or ytterbium-doped fluorides. Both halide perovskites and ytterbium-doped fluorides are photoluminescent materials, characterized by their ability to emit high-energy photons when excited by low-energy photons. Therefore, when the optical activation layer absorbs heat generated by the resonator and emits low-energy fluorescence, the optical cooling layer can be driven by the low-energy fluorescence to convert it into high-energy photons. The combination of the optical activation layer and the optical cooling layer achieves the goal of converting thermal energy into and consuming light energy. Limiting the optical cooling layer to halide perovskites or ytterbium-doped fluorides clarifies the range of materials available for the optical cooling layer, ensuring that the optical cooling layer can effectively achieve optical cooling, thereby guaranteeing device performance.

[0054] In some embodiments, the bottom electrode 300 and the top electrode 500 are both made of any one or more materials selected from the group consisting of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf.

[0055] In some embodiments, the piezoelectric layer 400 is made of AlN, 、 、 Made of any material.

[0056] In some embodiments, the substrate 100 is made of any one of Si, sapphire, and SiC; the support layer 200 is made of , SiC, or any one or more materials.

[0057] The present invention provides a filter comprising the self-temperature-controlled bulk acoustic wave resonator in the above embodiment.

[0058] Reference Attachment Figure 2 and attached Figure 3 The present invention provides a method for preparing the self-temperature-controlled bulk acoustic wave resonator in the above embodiment, comprising the following steps:

[0059] S1. After forming a groove on the upper surface of the substrate, a sacrificial layer is grown on the groove;

[0060] S2. A support layer, a bottom electrode, a piezoelectric layer, and a top electrode covering the groove are sequentially formed on the upper surface of the substrate;

[0061] S3. Spin-coating a light-activated layer on the top electrode;

[0062] S4. After the light-activated layer is dried, a light-activated layer is spin-coated on the light-activated layer;

[0063] S5. Release the sacrificial layer to form a cavity between the substrate and the supporting layer, thereby obtaining a self-temperature-controlled bulk acoustic wave resonator.

[0064] In step S1, a groove is formed on the upper surface of the substrate to provide a structural foundation for the subsequent formation of the cavity. The groove can be formed by etching. A sacrificial layer is grown on the groove to be released in the subsequent step to form the cavity structure.

[0065] In step S2, a support layer, bottom electrode, piezoelectric layer, and top electrode are sequentially fabricated on the substrate's top surface. Together, these thin film layers form the basic structure of a bulk acoustic wave resonator. The support layer supports the thin film layers above it, the bottom and top electrodes apply electrical signals, and the piezoelectric layer is the functional layer that achieves acoustic-to-electrical conversion.

[0066] In steps S3 and S4, the optical activation layer and optical cooling layer are deposited on the top surface of the top electrode via spin coating. Spin coating is a common method for thin film deposition, achieving uniform film coverage. The optical activation layer is first spin-coated, and after drying, the optical cooling layer is then spin-coated to form a stacked structure.

[0067] In step S5, the sacrificial layer is released, forming a cavity between the substrate and the support layer. This cavity structure ensures that the resonator has good acoustic performance. The sacrificial layer is typically released using a wet etching process, using a suitable etchant to selectively remove the sacrificial layer without damaging other film layers.

[0068] Specifically, to address the problem of device failure caused by heating of high-frequency bulk acoustic wave resonators, this method provides an effective way to prepare a self-temperature-controlled bulk acoustic wave resonator. By preparing a light-starting layer and a light-cooling layer on the top electrode of the resonator, the conversion and consumption of thermal energy into light energy is achieved. When the resonator generates heat during operation, the light-starting layer absorbs the heat and emits low-energy fluorescence. Driven by the low-energy fluorescence, the light-cooling layer converts high-energy photons, thereby consuming the thermal energy in the form of light energy, reducing the device temperature, improving the device power capacity, and ensuring the stable operation of the device at high frequencies. The preparation method includes making grooves and sacrificial layers on the substrate to prepare for the subsequent formation of the cavity structure; through deposition and spin coating and other processes, the various film layers constituting the resonator and the light energy conversion functional layer are made on the upper surface of the substrate; by releasing the sacrificial layer, a bulk acoustic wave resonator with self-temperature-control function is finally formed.

[0069] In some specific embodiments, the substrate is first cleaned and dried using acetone and hydrofluoric acid, and then a 3 μm deep groove is prepared on the surface of the silicon substrate using a plasma etching method. A sacrificial layer is then grown using a PVD method with a thickness of 3.1 μm. The sacrificial layer is then polished, and a supporting layer is grown using plasma enhanced CVD technology with a thickness of 50 nm. A 500 nm thick bottom electrode is then deposited on the surface of the sacrificial layer using a PVD method. A piezoelectric layer with a thickness of 1 μm is then grown on the bottom electrode using PVD. A 500 nm thick top electrode is then grown on the piezoelectric layer using PVD. A 200 nm thick photo-activated layer is then grown on the top electrode using a spin coating method, and after drying, a 300 nm photo-cooling layer is spin-coated. Finally, the resonator is placed in gaseous hydrogen fluoride for release, and the sacrificial layer is removed by dry etching, thereby preparing the resonator.

[0070] In some specific embodiments, a silicon substrate is first selected, and a groove with a depth of 2 microns is formed on the upper surface of the silicon substrate through photolithography and etching processes. Subsequently, a sacrificial silicon dioxide layer with a thickness of 0.5 microns is grown on the groove by chemical vapor deposition. Next, a silicon nitride supporting layer with a thickness of 0.2 microns is deposited on the upper surface of the silicon substrate by chemical vapor deposition. A molybdenum bottom electrode, an aluminum nitride piezoelectric layer, and a gold top electrode are sequentially deposited by magnetron sputtering with thicknesses of 0.1 microns, 1 micron, and 0.1 microns, respectively. A thermoluminescent halide photo-start layer is then spin-coated on the upper surface of the gold top electrode at a speed of 1000 rpm for 30 seconds and dried at 100 degrees Celsius for 30 minutes. After the photo-start layer has dried, a halide perovskite photo-cooling layer is spin-coated on the upper surface of the photo-start layer at a speed of 800 rpm for 30 seconds. Finally, a hydrofluoric acid solution was used to release the silicon dioxide sacrificial layer to form a cavity structure, thereby fabricating a self-temperature-controlled bulk acoustic wave resonator.

[0071] The self-temperature-controlled bulk acoustic wave resonator prepared by the above embodiment can effectively solve the heating problem under high-frequency operation and improve the performance and reliability of the device.

[0072] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any actual relationship or order between these entities or operations.

[0073] Descriptions with reference to the terms "one embodiment," "certain embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0074] The foregoing description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A self-temperature controlled bulk acoustic wave resonator, comprising a substrate (100), a support layer (200), a bottom electrode (300), a piezoelectric layer (400), and a top electrode (500) stacked in sequence, wherein a cavity (600) is provided between the substrate (100) and the support layer (200), and characterized in that: A light start layer (700) and a light cooling layer (800) are sequentially stacked on the top electrode (500); the light start layer (700) is used to absorb heat generated by the resonator and stimulate low-energy fluorescence when a critical temperature is reached, and when the heat is lower than the critical temperature, it no longer emits light to drive the light cooling layer (800) to work; the light cooling layer (800) can convert high-energy photons under the drive of the low-energy fluorescence; the light start layer (700) and the light cooling layer (800) cooperate to convert thermal energy into light energy for consumption.

2. The self-temperature-controlled bulk acoustic wave resonator according to claim 1, characterized in that: The light-starting layer (700) is made of thermoluminescent material.

3. The self-temperature-controlled bulk acoustic wave resonator according to claim 2, characterized in that: The thermoluminescent material is any one of halides, sulfates, sulfides, binary oxides or ternary oxides that emit light under heat.

4. The self-temperature-controlled bulk acoustic wave resonator according to claim 1, characterized in that: The optical cooling layer (800) is made of photoluminescent material.

5. The self-temperature-controlled bulk acoustic wave resonator according to claim 4, characterized in that: The photoluminescent material is a halide perovskite or ytterbium-doped fluoride.

6. The self-temperature-controlled bulk acoustic wave resonator according to claim 1, characterized in that: The bottom electrode (300) and the top electrode (500) are both made of any one or more materials selected from the group consisting of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb, and Hf.

7. The self-temperature-controlled bulk acoustic wave resonator according to claim 1, characterized in that: The piezoelectric layer (400) is made of AlN, 、 、 Made of any material.

8. The self-temperature-controlled bulk acoustic wave resonator according to claim 1, characterized in that: The substrate (100) is made of any one of Si, sapphire, and SiC; the support layer (200) is made of , SiC, or any one or more materials.

9. A filter, characterized in that: The invention comprises the self-temperature-controlled bulk acoustic wave resonator according to any one of claims 1 to 8.

10. A method for preparing the self-temperature-controlled bulk acoustic wave resonator according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. After forming a groove on the upper surface of the substrate, a sacrificial layer is grown on the groove; S2. A support layer, a bottom electrode, a piezoelectric layer and a top electrode covering the groove are sequentially formed on the upper surface of the substrate; S3. Spin-coating a light-activated layer on the top electrode; S4. After the optical activation layer is dried, a light refrigeration layer is spin-coated on the optical activation layer; S5. releasing the sacrificial layer to form a cavity between the substrate and the supporting layer, thereby manufacturing the self-temperature-controlled bulk acoustic wave resonator.

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