High-sensitivity self-heating surface acoustic wave chemical sensor and preparation method thereof

Abstract

The invention provides a high-sensitivity self-heating surface acoustic wave chemical sensor and a preparation method thereof. The high-sensitivity self-heating surface acoustic wave chemical sensor comprises a piezoelectric film; the transduction mechanism comprises a sensitive layer, an input transducer and an output transducer; the heating mechanism is arranged corresponding to the sensitive layer and comprises an electric heating body and an electrode; one end of the composite supporting piece is connected to the piezoelectric film and arranged on the same side as the heating mechanism, and the other end of the composite supporting piece is supported on the workbench. According to the invention, the desorption capacity of the sensitive layer after the gas to be detected is adsorbed is improved, the purpose of enhancing the recovery efficiency of the sensitive layer is further achieved, and meanwhile, the piezoelectric film can be adopted to replace a blocky piezoelectric crystal structure, so that the problems that the overall thickness of the structure is relatively large, the detection sensitivity degree is not high and the application range is limited can be fundamentally solved. Compared with an existing conventional structure, the sensor has the advantages of being high in operation efficiency, wide in application scene, high in sensitivity, high in reliability and small in size, and a new thought is provided for processing and preparation of the sensor.

Description

Technical Field

[0001] The invention relates to the technical field of sensors, and in particular to a highly sensitive self-heating surface acoustic wave chemical sensor and a preparation method thereof. Background Art

[0002] With the increasing attention paid to environmental protection worldwide, the monitoring and control of polluting gases emitted by industries, such as sulfides, specific chemical gases, and volatile organic compounds (VOCs), has become particularly important. In order to effectively detect these gases, it is urgent to develop gas sensors with high sensitivity, good selectivity, small size and low cost.

[0003] SAW gas sensors are mainly composed of piezoelectric materials, interdigital transducers on piezoelectric materials, and sensitive layers between the interdigital transducers. The physical properties of the surface acoustic waves generated by the interdigital transducers, such as frequency, amplitude, phase, etc., will be different before and after the adsorption of gas. The surface acoustic wave gas sensor detects gas by detecting these differences. However, traditional SAW gas sensors are made based on thick piezoelectric plates (such as quartz, lithium niobate, etc.), and their sensor sensitivity is not high. At the same time, it is difficult to achieve the desorption of chemical gases. The current method of improving sensitivity is generally achieved by increasing the device frequency or using a special nano-adsorption layer, but the overall effect is limited.

[0004] In order to overcome the above problems, the current SAW gas sensors are gradually developed to be processed using piezoelectric crystal structures. However, due to the limitations of processing technology, they can only be processed through block piezoelectric crystal structures at this stage, resulting in a large overall thickness of the structure, making it difficult to achieve high-sensitivity detection, and cannot be used for small-dose (trace) gas measurement, which is not suitable for current high-precision gas detection needs.

[0005] In addition, the reversibility of the film in the sensitive layer area is crucial to the performance of the surface acoustic wave gas sensor, which means that the sensitive layer area has both adsorption and desorption effects on the gas. When the concentration of the gas to be measured increases, the sensitive layer area can quickly capture the gas to be measured and achieve effective adsorption; and when the concentration of the gas to be measured decreases, the sensitive layer area can desorb the gas to be measured and return to its initial state. However, most of the current desorption methods use natural recovery at room temperature or the introduction of inert gas to accelerate the rapid recovery of the film in the sensitive layer area, which not only affects the measurement accuracy of the sensor to a certain extent and reduces the number of times the sensor is used, but is also likely to limit the detection and application range of the device. Therefore, in view of the shortcomings of existing SAW gas sensors in sensitivity, desorption performance and processing technology, it is necessary to develop a new type of SAW gas sensor to achieve high sensitivity, high reliability, miniaturization and good reversibility of gas detection technology. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problems of limited sensor accuracy and limited sensitive layer recovery efficiency in the prior art, and to provide a highly sensitive self-heating surface acoustic wave chemical sensor and a preparation method thereof.

[0007] To solve the above technical problems, the present invention provides a highly sensitive self-heating surface acoustic wave chemical sensor, which includes: a piezoelectric film; a transducer mechanism, which is connected to one side of the piezoelectric film and includes a sensitive layer, an input transducer and an output transducer, wherein the input transducer and the output transducer are respectively arranged on opposite sides of the sensitive layer along a first direction; a heating mechanism, which is connected to the other side of the piezoelectric film and is arranged corresponding to the sensitive layer, and includes an electric heating body and an electrode, and the electrode is externally connected to a power supply device; at least one composite support member, one end of the composite support member is connected to the piezoelectric film and is arranged on the same side as the heating mechanism, and the other end is supported on a workbench.

[0008] In one embodiment of the present invention, the input transducer and the output transducer are internally configured as a finger structure, a plurality of the fingers are evenly spaced along a first direction, and the ratio of the width of any finger in the first direction to the spacing distance between two adjacent fingers is 0.45~0.55.

[0009] In one embodiment of the present invention, the transducer mechanism further includes an input metal reflective grating and an output metal reflective grating, wherein the input metal reflective grating is arranged on a side of the input transducer away from the sensitive layer in the first direction, and the output metal reflective grating is arranged on a side of the output transducer away from the sensitive layer in the first direction.

[0010] In one embodiment of the present invention, the input metal reflective grating and the output metal reflective grating are both open-circuit reflective gratings.

[0011] In one embodiment of the present invention, the composite support comprises a silicon dioxide layer and a silicon layer connected to each other, wherein the silicon dioxide layer is connected to the piezoelectric film.

[0012] In one embodiment of the present invention, the piezoelectric film is a single crystal film or a polycrystalline film; the input transducer and the output transducer substrates are a composite material of aluminum, platinum or chromium / gold.

[0013] In one embodiment of the present invention, the electric heating element is configured as: one of a right-angle serpentine arrangement structure, an arc-shaped serpentine arrangement structure or a honeycomb structure surrounded by electric heating wires.

[0014] The present invention also provides a method for preparing a high-sensitivity self-heating surface acoustic wave chemical sensor, which is used to prepare the high-sensitivity self-heating surface acoustic wave chemical sensor described in Example 1, and comprises: step S1, connecting a transition support member to the bottom surface of a clean piezoelectric film, and supporting the transition support member on a workbench; step S2, connecting a heating mechanism on the top surface of the piezoelectric film; step S3, coating the heating mechanism with a bonding layer and polishing it to a smooth surface; step S4, after connecting a composite support member to the surface of the bonding layer, turning it over as a whole so that the composite support member is supported on the workbench; step S5, removing the transition support member to expose the piezoelectric film; step S6, preparing a transducer mechanism on the exposed piezoelectric film; step S7, etching the composite support member to expose the heating mechanism at the corresponding position of the sensitive layer, and obtaining the target high-sensitivity self-heating surface acoustic wave chemical sensor.

[0015] In one embodiment of the present invention, the transition support member includes a transition silicon dioxide layer and a transition silicon layer, the composite support member includes a silicon dioxide layer and a silicon layer, the bonding layer substrate is silicon dioxide, wherein the transition silicon dioxide layer is connected to the piezoelectric film, and the silicon dioxide layer and the bonding layer are bonded to each other.

[0016] In one embodiment of the present invention, in step S2, the heating mechanism is obtained after the electric heating body is photolithographically formed, and the heating mechanism is connected to the piezoelectric film by magnetron sputtering; in step S3, a bonding layer is coated on the outside of the heating mechanism by plasma enhanced chemical vapor deposition; in step S6, a sensitive layer, an input transducer, an output transducer, an input metal reflective grating and an output metal reflective grating are prepared on the piezoelectric film respectively, wherein the input transducer, the output transducer, the input metal reflective grating and the output metal reflective grating are all formed into a finger structure by photolithography and magnetron sputtering.

[0017] The above technical solution of the present invention has the following advantages compared with the prior art: The highly sensitive self-heating surface acoustic wave chemical sensor and its preparation method described in the present invention heat the sensitive layer through the heating mechanism in the mechanism, thereby facilitating the improvement of the desorption capacity of the sensitive layer after adsorbing the gas to be measured, thereby achieving the purpose of enhancing the recovery efficiency of the sensitive layer. At the same time, the present application forms a stable support for the piezoelectric structure based on the setting of the composite support, thereby achieving the purpose of replacing the block piezoelectric crystal structure with a piezoelectric film, thereby fundamentally solving the problems of the overall thickness of the structure being large, the detection sensitivity being low, and the scope of use being limited. In addition, based on the above structure, the double-sided processing of the piezoelectric film becomes possible, thereby overcoming the deficiency in the prior art that only single-sided electrodes can be made on the piezoelectric structure. Compared with the existing conventional structures, the present application has the advantages of high operating efficiency, wide application scenarios, high sensitivity, high reliability and miniaturization, providing a new idea for the processing and preparation of sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0019] Figure 1 3D schematic diagram of the structure of a highly sensitive self-heating surface acoustic wave chemical sensor in a preferred embodiment of the present invention; Figure 2 yes Figure 1 A top view of the highly sensitive self-heating surface acoustic wave chemical sensor shown; Figure 3 yes Figure 1 A schematic diagram of the connection structure between the heating mechanism and the piezoelectric film in the highly sensitive self-heating surface acoustic wave chemical sensor; Figure 4 is a schematic diagram of the three-dimensional structure of a heating mechanism in another embodiment of the present invention; Figure 5 is a schematic diagram of the three-dimensional structure of the heating mechanism in the third embodiment of the present invention; Figure 6 is a schematic diagram of the three-dimensional structure of the heating mechanism in the fourth embodiment of the present invention; Figure 7 It is a schematic diagram of the process structure of a method for preparing a highly sensitive self-heating surface acoustic wave chemical sensor in the fifth embodiment of the present invention.

[0020] Explanation of the reference numerals in the specification: 100, piezoelectric film; 200, transducer mechanism; 210, input transducer; 220, output transducer; 230, input metal reflective grating; 240, output metal reflective grating; 250, sensitive layer; 300, composite support; 400, heating mechanism; 410, electric heating element; 420, electrode; 500, transition support; 600, bonding layer; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention. Embodiment 1

[0022] See also Figure 1 As shown, this embodiment provides a highly sensitive self-heating surface acoustic wave chemical sensor, which includes: a piezoelectric film 100; a transducer mechanism 200, the transducer mechanism 200 is connected to one side of the piezoelectric film 100, and includes a sensitive layer 250, an input transducer 210 and an output transducer 220, wherein the input transducer 210 and the output transducer 220 are respectively arranged on opposite sides of the sensitive layer 250 along a first direction X; a heating mechanism 400, the heating mechanism 400 is connected to the other side of the piezoelectric film 100 and is arranged corresponding to the sensitive layer 250, and includes an electric heating body 410 and an electrode 420, and the electrode 420 is externally connected to a power supply device; at least one composite support member 300, one end of the composite support member 300 is connected to the piezoelectric film 100 and is arranged on the same side as the heating mechanism 400, and the other end is supported on a workbench.

[0023] The highly sensitive self-heating surface acoustic wave chemical sensor described in this embodiment heats the sensitive layer 250 through the heating mechanism 400 in its mechanism, thereby facilitating the improvement of the desorption capacity of the sensitive layer 250 after adsorbing the gas to be measured, thereby achieving the purpose of enhancing the recovery efficiency of the sensitive layer 250. At the same time, the present application forms a stable support for the piezoelectric structure based on the setting of the composite support 300, thereby achieving the purpose of replacing the bulk piezoelectric crystal structure with the piezoelectric film 100, thereby fundamentally solving the problems of the overall thickness of the structure being large, the detection sensitivity being low, and the limited scope of use. In addition, based on the above structure, it is also possible to process the piezoelectric film 100 on both sides, thereby overcoming the deficiency of the prior art that only single-sided electrodes 420 can be made on the piezoelectric structure. Compared with the existing conventional structures, the present application has the advantages of high operating efficiency, wide application scenarios, high sensitivity, high reliability and miniaturization, providing a new idea for the processing and preparation of sensors.

[0024] It is worth noting that, for the convenience of description, in this embodiment, the length direction of the high-sensitivity self-heating surface acoustic wave chemical sensor is defined as the first direction X, the width direction of the high-sensitivity self-heating surface acoustic wave chemical sensor is defined as the second direction Y, and the height direction of the high-sensitivity self-heating surface acoustic wave chemical sensor is defined as the third direction Z, wherein the first direction X, the second direction Y and the third direction Z are arranged perpendicular to each other in pairs, and the first direction X and the second direction Y are located in the same plane.

[0025] See also Figure 1 As shown, the piezoelectric film 100 in this embodiment is preferably a single crystal lithium niobate film. When cutting it, in order to describe the process of rotating the piezoelectric material obtained by cutting in practical applications, the Euler angles (α, β, γ) are usually used to describe it, specifically: first rotate the Z axis of the original coordinate system (X, Y, Z) by an angle of α to obtain a new coordinate system (X', Y', Z'). Then rotate around the X' axis by an angle of β to obtain (X", Y", Z"), and finally rotate around the Z' axis by an angle of γ to obtain the final coordinate system. The Euler angles determine the cutting direction of the substrate and the propagation direction of the sound wave. In different embodiments, the piezoelectric film 100 can be configured as a single crystal film or a polycrystalline film, and the present invention does not impose specific limitations on this.

[0026] The present embodiment includes two composite support members 300, which are respectively supported at both ends of the piezoelectric film 100 in the first direction X to improve the support stability of the sensor. Specifically, the two composite support members 300 in the present embodiment are obtained by etching a complete structure connected to the bottom of the piezoelectric film 100, and the specific number and connection position of the composite support members 300 can be adaptively adjusted according to actual use requirements. Furthermore, the composite support member 300 in the present embodiment includes a silicon dioxide layer and a silicon layer connected to each other, wherein the silicon dioxide layer is connected to the piezoelectric film 100. Among them, silicon provides good mechanical strength and toughness, while silicon dioxide increases the hardness and wear resistance of the material.

[0027] See also Figure 2 As shown, in this embodiment, the input transducer 210 and the output transducer 220 are both configured as interdigital structures, and a plurality of interdigital structures are evenly spaced along the first direction X, and the ratio of the width of any interdigital structure in the first direction X to the spacing distance between two adjacent interdigital structures is about 0.50. Specifically, when the input transducer 210 receives an alternating voltage signal, due to the inverse piezoelectric effect of the piezoelectric film 100, a sound wave propagating along the first direction X is generated. When the sound wave passes through the sensitive layer 250, the mass, conductivity, viscosity coefficient, etc. of the sensitive layer 250 will change, thereby changing the characteristics of the sound wave passing thereon, thereby changing the wave velocity and frequency of the sound wave, until the sound wave is transmitted to the output transducer 220, it will convert the sound wave into an alternating signal output based on the piezoelectric effect, thereby realizing the sensing process. The substrates of the input transducer 210 and the output transducer 220 are both chromium / gold composite materials. In other embodiments, they can also be configured as one of aluminum or platinum, and the present invention does not make specific restrictions on this.

[0028] Furthermore, the transducer mechanism 200 further includes an input metal reflective grating 230 and an output metal reflective grating 240, wherein the input metal reflective grating 230 is arranged on a side of the input transducer 210 away from the sensitive layer 250 in the first direction X, and the output metal reflective grating 240 is arranged on a side of the output transducer 220 away from the sensitive layer 250 in the first direction X. Wherein, the input metal reflective grating 230 and the output metal reflective grating 240 are both open-circuit reflective gratings. Wherein, the input metal reflective grating 230 can form a standing wave between the input transducer 210 and the sensitive layer 250, thereby enhancing the amplitude and stability of the acoustic wave signal. The output metal reflective grating 240 can receive the surface acoustic wave processed by the sensitive layer 250, and reflect it back to the output transducer 220 for signal detection and analysis.

[0029] See also Figure 3 As shown, the heating mechanism 400 in this embodiment includes an electric heating body 410 and two electrodes 420 connected to opposite sides of the electric heating body 410. The two electrodes 420 are respectively connected to power supply devices to achieve circuit conduction. The electric heating body 410 is configured as a right-angle serpentine arrangement structure surrounded by electric heating wires. The serpentine arrangement of electric heating wires can provide a more uniform heating effect because they can cover a larger area and the heat can be more evenly distributed in the heating area. At the same time, it can also improve the safety of the heating equipment and reduce the risks caused by overheating or poor contact. In this embodiment, the substrate of the heating mechanism 400 is preferably metal platinum with a high electrothermal effect. Embodiment 2

[0030] This embodiment provides another highly sensitive self-heating surface acoustic wave chemical sensor, whose main structural arrangement and connection method are the same as those in the first embodiment and will not be elaborated herein. In this embodiment, only the electrode 420 of the heating mechanism 400 is connected to the plane diagonal line of the electric heating body 410 to provide another feasible implementation structure. Embodiment 3

[0031] This embodiment provides another highly sensitive self-heating surface acoustic wave chemical sensor, wherein the electric heating body 410 is configured as an arc-shaped serpentine arrangement structure surrounded by electric heating wires. Embodiment 4

[0032] This embodiment provides another highly sensitive self-heating surface acoustic wave chemical sensor, wherein the electric heating body 410 is configured as a honeycomb structure surrounded by heating wires, thereby enabling a higher density of heating wires to be arranged per unit area, thereby achieving a faster electrothermal conversion efficiency. Embodiment 5

[0033] This embodiment provides a method for preparing a highly sensitive self-heating surface acoustic wave chemical sensor, which is used to prepare the highly sensitive self-heating surface acoustic wave chemical sensor described in Embodiment 1, and comprises: Step S1, connecting a transition support 500 to the bottom surface of the clean piezoelectric film 100, and supporting the transition support 500 on a workbench; further, the transition support 500 in this embodiment includes a transition silicon dioxide layer and a transition silicon layer, and the transition silicon dioxide layer is connected to the piezoelectric film 100, see Figure 7 (a) in the figure.

[0034] Step S2, connecting the heating mechanism 400 to the top surface of the piezoelectric film 100; further, in this embodiment, after the electric heating body 410 is photolithographically formed, the heating mechanism 400 is obtained, and the heating mechanism 400 is connected to the piezoelectric film 100 by magnetron sputtering, see Figure 7 (b) in the figure.

[0035] Step S3, coating the bonding layer 600 on the outside of the heating mechanism 400, and polishing the surface to a smooth surface; further, in this embodiment, the bonding layer 600 is coated on the outside of the heating mechanism 400 by plasma enhanced chemical vapor deposition (PECVD). Specifically, the bonding layer 600 substrate is silicon dioxide, see Figure 7 (c) in.

[0036] Step S4, see Figure 7 (d) ~ Figure 7 In (e), after the composite support member 300 is connected to the surface of the bonding layer 600, it is turned over as a whole so that the composite support member 300 is supported on the workbench; further, in this embodiment, the composite support member 300 includes a silicon dioxide layer and a silicon layer, and the silicon dioxide layer and the bonding layer 600 are bonded by SiO2-SiO2 through a wafer bonding process.

[0037] Step S5: remove the transition support 500 to expose the piezoelectric film 100; see Figure 7 (f) in.

[0038] Step S6, preparing a transducer mechanism 200 on the exposed piezoelectric film 100; further, in this embodiment, a sensitive layer 250, an input transducer 210, an output transducer 220, an input metal reflective grating 230 and an output metal reflective grating 240 are prepared on the piezoelectric film 100, wherein the input transducer 210, the output transducer 220, the input metal reflective grating 230 and the output metal reflective grating 240 are all formed into a cross-finger structure by photolithography and magnetron sputtering. For details, see Figure 7(g) in.

[0039] Step S7: Etching the composite support 300 to expose the heating mechanism 400 at the corresponding position of the sensitive layer 250, thereby obtaining the target highly sensitive self-heating surface acoustic wave chemical sensor. Figure 7 (h) in.

[0040] In summary, the highly sensitive self-heating surface acoustic wave chemical sensor and its preparation method described in the present invention heats the sensitive layer 250 through the heating mechanism 400 in its mechanism, thereby facilitating the improvement of the desorption capacity of the sensitive layer 250 after adsorbing the gas to be measured, thereby achieving the purpose of enhancing the recovery efficiency of the sensitive layer 250. At the same time, the present application forms a stable support for the piezoelectric structure based on the setting of the composite support 300, thereby achieving the purpose of replacing the bulk piezoelectric crystal structure with the piezoelectric film 100, thereby fundamentally solving the problems of the overall thickness of the structure being large, the detection sensitivity being low, and the limited scope of use. In addition, based on the above structure, the double-sided processing of the piezoelectric film 100 is also possible, thereby overcoming the deficiency in the prior art that only single-sided electrodes 420 can be made on the piezoelectric structure. Compared with the existing conventional structures, the present application has the advantages of high operating efficiency, wide application scenarios, high sensitivity, high reliability and miniaturization, and provides a new idea for the processing and preparation of sensors.

[0041] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A highly sensitive self-heating surface acoustic wave chemical sensor, characterized in that: include: Piezoelectric film; A transducer mechanism, the transducer mechanism is connected to one side of the piezoelectric film, and comprises a sensitive layer, an input transducer and an output transducer, wherein the input transducer and the output transducer are respectively arranged on two opposite sides of the sensitive layer along a first direction; A heating mechanism, the heating mechanism is connected to the other side of the piezoelectric film and is arranged corresponding to the sensitive layer, and comprises an electric heating body and an electrode, and the electrode is externally connected to a power supply device; At least one composite support member, one end of which is connected to the piezoelectric film and is arranged on the same side as the heating mechanism, and the other end of which is supported on the workbench.

2. The highly sensitive self-heating surface acoustic wave chemical sensor according to claim 1, characterized in that: The input transducer and the output transducer are both configured as a finger structure, and a plurality of the fingers are evenly spaced along the first direction, and the ratio of the width of any finger in the first direction to the spacing distance between two adjacent fingers is 0.45-0.

55.

3. The highly sensitive self-heating surface acoustic wave chemical sensor according to claim 1, characterized in that: The transducer mechanism also includes an input metal reflective grating and an output metal reflective grating. The input metal reflective grating is arranged on a side of the input transducer away from the sensitive layer in the first direction, and the output metal reflective grating is arranged on a side of the output transducer away from the sensitive layer in the first direction.

4. The highly sensitive self-heating surface acoustic wave chemical sensor according to claim 3, characterized in that: The input metal reflective grating and the output metal reflective grating are both open-circuit reflective gratings.

5. The highly sensitive self-heating surface acoustic wave chemical sensor according to claim 1, characterized in that: The composite support member includes a silicon dioxide layer and a silicon layer connected to each other, wherein the silicon dioxide layer is connected to the piezoelectric film.

6. The highly sensitive self-heating surface acoustic wave chemical sensor according to claim 1, characterized in that: The piezoelectric film is a single crystal film or a polycrystalline film; the input transducer and the output transducer substrates are a composite material of aluminum, platinum or chromium / gold.

7. The highly sensitive self-heating surface acoustic wave chemical sensor according to claim 1, characterized in that: The electric heating body is configured as one of a right-angle serpentine arrangement structure, an arc-shaped serpentine arrangement structure or a honeycomb structure surrounded by electric heating wires.

8. A method for preparing a highly sensitive self-heating surface acoustic wave chemical sensor, characterized in that: The method is used to prepare the highly sensitive self-heating surface acoustic wave chemical sensor according to any one of claims 1 to 7, comprising: Step S1, connecting a transition support member to the bottom surface of a clean piezoelectric film, and supporting the transition support member on a workbench; Step S2, connecting a heating mechanism to the top surface of the piezoelectric film; Step S3, coating the heating mechanism with a bonding layer and polishing the surface to a smooth surface; Step S4, after the composite support is connected to the surface of the bonding layer, the bonding layer is turned over as a whole so that the composite support is supported on the workbench; Step S5, removing the transition support to expose the piezoelectric film; Step S6, preparing a transducer mechanism on the exposed piezoelectric film; Step S7, etching the composite support member to expose the heating mechanism at a location corresponding to the sensitive layer, thereby obtaining a target highly sensitive self-heating surface acoustic wave chemical sensor.

9. The method for preparing a highly sensitive self-heating surface acoustic wave chemical sensor according to claim 8, characterized in that: The transition support member includes a transition silicon dioxide layer and a transition silicon layer, the composite support member includes a silicon dioxide layer and a silicon layer, the bonding layer substrate is silicon dioxide, wherein the transition silicon dioxide layer is connected to the piezoelectric film, and the silicon dioxide layer and the bonding layer are bonded to each other.

10. The method for preparing a highly sensitive self-heating surface acoustic wave chemical sensor according to claim 8, characterized in that: In step S2, the heating mechanism is obtained after photolithography forming of the electric heating element, and the heating mechanism is connected to the piezoelectric film by magnetron sputtering; in step S3, a bonding layer is coated on the outside of the heating mechanism by plasma enhanced chemical vapor deposition; in step S6, a sensitive layer, an input transducer, an output transducer, an input metal reflective grating and an output metal reflective grating are prepared on the piezoelectric film respectively, wherein the input transducer, the output transducer, the input metal reflective grating and the output metal reflective grating are all formed into a finger structure by photolithography and magnetron sputtering.

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