Wafer-level preparation method of tungsten trioxide nanosheet hydrogen sensing layer material

Abstract

The invention discloses a wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material, which comprises the following steps: forming an amorphous tungsten trioxide film through magnetron reactive sputtering, enabling the substance tungsten trioxide in the amorphous tungsten trioxide film to be in an amorphous state, and enabling the amorphous tungsten trioxide film to have higher surface energy and reaction activity at the moment; only the target material WO3 is used during magnetron reactive sputtering, impurities are prevented from being introduced into the amorphous tungsten trioxide film, hydrochloric acid is adopted for etching the amorphous tungsten trioxide film, the amorphous tungsten trioxide is subjected to hydration reaction at the moment, stable hydrated tungsten trioxide is generated, and then the amorphous tungsten trioxide film is prepared. Carrying out self-assembly on the hydrated tungsten trioxide to form a hydrated WO3 nanosheet porous film, namely a tungsten trioxide nanosheet; the method has the advantages that large-scale and uniform production of tungsten trioxide nanosheet hydrogen sensing layer materials with rich nanostructures, high chemical purity and specific crystal phases can be realized, and wafer-level preparation can be realized.

Description

Technical Field

[0001] The invention relates to a wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensor layer material, in particular to a preparation method of a tungsten trioxide nanosheet hydrogen sensor layer material. Background Art

[0002] The development of hydrogen (H2) sensors with high sensitivity and fast response / recovery time is crucial to meet the growing demand for hydrogen use and reduce the risk of explosion during its production, transportation and use. The core component of hydrogen sensors is the hydrogen sensing layer material, and the performance of the hydrogen sensing layer material determines the overall performance of the hydrogen sensor. Therefore, the preparation of high-performance hydrogen sensing layer materials has become a key task in hydrogen sensor research.

[0003] Tungsten trioxide (WO3) has been widely studied and applied in the field of hydrogen sensing layer materials due to its adjustable energy band structure, unique reversible reaction characteristics with hydrogen, and low cost and environmentally friendly advantages. Hydrogen sensing layer materials prepared using WO3 need to have WO3 with rich nanostructures, high chemical purity and specific crystal phases to increase the active sites of surface sensing and catalytic reactions in order to achieve high sensitivity to hydrogen.

[0004] At present, the processes for preparing hydrogen sensing layer materials using WO3 are usually hydrothermal method, gel sol method, etc. Although these preparation processes can make hydrogen sensing layer materials have WO3 with rich nanostructure, high chemical purity and specific crystal phase, they are highly complex and usually incompatible with semiconductor device manufacturing processes, which limits the large-scale and uniform production of tungsten trioxide nanosheet hydrogen sensing layer materials with rich nanostructure, high chemical purity and specific crystal phase, especially in wafer-level preparation. There are technical barriers. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a wafer-level preparation method of tungsten trioxide nanosheet hydrogen sensor layer materials that can realize large-scale and uniform production of tungsten trioxide nanosheet hydrogen sensor layer materials with rich nanostructure, high chemical purity and specific crystal phase, and can realize wafer-level preparation of tungsten trioxide nanosheet hydrogen sensor layer materials.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: a wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material, comprising the following steps:

[0007] Step 1, cleaning and drying a double-sided polished four-inch silicon wafer to obtain a clean silicon wafer for standby use;

[0008] Step 2: Place the clean silicon wafer obtained in step 1 on the sample table of the magnetron sputtering equipment, and first evacuate the vacuum degree of the magnetron sputtering equipment to no more than 9×10-4 Pa, then introduce working gas to make the working gas pressure of the magnetron sputtering equipment to 0.4-0.7Pa, and set the sputtering power of the magnetron sputtering equipment to 40-75W, the sputtering time to 20-40 minutes, the sample stage temperature to room temperature, the sample stage speed to 20-40rpm, use WO3 with a mass purity of not less than 99.99% as the target material, start the magnetron sputtering equipment to sputter WO3 to the clean silicon wafer on the sample stage, and form an amorphous tungsten trioxide film with a thickness of 200nm to 400nm on the surface of the clean silicon wafer, and obtain a silicon wafer with an amorphous tungsten trioxide film on the surface;

[0009] Step 3, immersing the silicon wafer with the amorphous tungsten trioxide film on the surface obtained in step 2 in a 0.1-0.5 mol / L hydrochloric acid (HCl) solution for 10-24 hours, then taking it out and drying it, at which time the amorphous tungsten trioxide film undergoes a hydration reaction to form a hydrated WO3 nanosheet porous film, thereby obtaining a silicon wafer with a hydrated WO3 nanosheet porous film;

[0010] Step 4: Place the silicon wafer with the hydrated WO3 nanosheet porous film obtained in step 3 in the air and anneal it at 350-450°C for 2-3 hours, at which time the hydrated WO3 nanosheet porous film forms a tungsten trioxide nanosheet hydrogen sensing layer material.

[0011] Compared with the prior art, the invention has the advantages that an amorphous tungsten trioxide film is first formed by magnetron reactive sputtering, and the tungsten trioxide in the amorphous tungsten trioxide film is in an amorphous state. At this time, the amorphous tungsten trioxide film has higher surface energy and reaction activity, and only the target material WO3 is used in the magnetron reactive sputtering, so that the introduction of impurities into the amorphous tungsten trioxide film is avoided, and then the amorphous tungsten trioxide film is etched with hydrochloric acid, and at this time, the amorphous tungsten trioxide produces a hydration reaction to generate stable hydrated tungsten trioxide, and the hydrated tungsten trioxide is self-assembled to form a hydrated WO3 nanosheet porous film, and then annealing can be performed to obtain a tungsten trioxide nanosheet. The invention combines magnetron reactive sputtering and By combining the method with chemical etching, a tungsten trioxide nanosheet hydrogen sensing layer material with a high aspect ratio (i.e., rich nanostructure), high chemical purity, and a specific crystal phase was successfully synthesized on a large scale. Since both magnetron reactive sputtering and chemical etching techniques are compatible with semiconductor device manufacturing processes, the process conditions of the present invention are easy to control, and the results have good repeatability. The large-scale and uniform production of the tungsten trioxide nanosheet hydrogen sensing layer material with rich nanostructure, high chemical purity, and a specific crystal phase can be achieved, and wafer-level preparation can be achieved. When the tungsten trioxide nanosheet hydrogen sensing layer material prepared by the method of the present invention is used in a hydrogen sensor, when the concentration of H2 is 1000ppm, its sensitivity reaches 1.41x 10 4, the response-recovery time reaches 5.3 seconds and 87.6 seconds respectively, which can significantly improve the high sensitivity of the hydrogen sensor to hydrogen.

[0012] Furthermore, in the step 1, the thickness of the double-sided polished four-inch silicon wafer is 380um, and the specific process of cleaning and drying the double-sided polished four-inch silicon wafer is: ultrasonic cleaning in acetone solution for 5-10 minutes, ultrasonic cleaning in anhydrous ethanol for 5-10 minutes, and finally cleaning with deionized water and drying.

[0013] Furthermore, in step 2, the working gas is a mixed gas of argon (Ar) with a mass purity of not less than 99.99% and oxygen (O2) with a mass purity of not less than 99.99%.

[0014] Furthermore, in the step 2, when the working gas is introduced, the gas flow rate of Ar is 20-60 sccm, and the gas flow rate of O2 is 4-20 sccm.

[0015] Furthermore, in the step 2, when the working gas is introduced, the gas flow rate of Ar is 40 sccm and the gas flow rate of O2 is 4 sccm.

[0016] Furthermore, in the step 2, when the working gas is introduced, the gas flow rate of Ar is 40 sccm and the gas flow rate of O2 is 12 sccm.

[0017] Furthermore, in the step 2, when the working gas is introduced, the gas flow rate of Ar is 40 sccm and the gas flow rate of O2 is 20 sccm. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a scanning electron microscope (SEM) image of the surface of the amorphous WO3 film prepared in Example 1 of the present invention;

[0019] Figure 2 The X-ray diffraction patterns (XRD) of WO3 thin films prepared at different stages in Example 1 of the present invention: (a) after sputtering, (b) after etching with HCl, and (c) after annealing in air;

[0020] Figure 3 This is a SEM image of the hydrated WO3 nanosheet obtained after etching in Example 1 of the present invention;

[0021] Figure 4 This is a SEM image of the WO3 nanosheet obtained after air annealing in Example 1 of the present invention;

[0022] Figure 5 This is the Raman spectrum (Raman) of the WO3 nanosheets obtained after air annealing in Example 1 of the present invention;

[0023] Figure 6 This is a SEM image of the WO3 nanosheet obtained after air annealing in Example 2 of the present invention;

[0024] Figure 7 This is a SEM image of the WO3 nanosheets obtained after air annealing in Example 3 of the present invention;

[0025] Figure 8 This is a SEM image of the WO3 nanosheet obtained after air annealing in Example 4 of the present invention;

[0026] Fig. 9 This is a SEM image of the WO3 nanosheet obtained after air annealing in Example 5 of the present invention;

[0027] Fig.10 This is a wafer-level image of a hydrogen sensor of palladium-loaded WO3 nanosheets obtained in Example 5 of the present invention;

[0028] Fig.11 This is a SEM image of the palladium-loaded WO3 nanosheets on the surface of the hydrogen sensor in Example 5 of the present invention;

[0029] Fig.12 This is an optical image of a single hydrogen sensor device in Example 5 of the present invention;

[0030] Fig.13 This is a hydrogen sensitivity test diagram of the sensor of palladium-loaded WO3 nanosheets at different temperatures in Example 5 of the present invention;

[0031] Fig.14 This is a statistical diagram of the response and recovery time of the sensor of palladium-loaded WO3 nanosheets at different temperatures in Example 5 of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below with reference to the accompanying drawings.

[0033] Embodiment 1: A wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material comprises the following steps:

[0034] Step 1, cleaning and drying a double-sided polished four-inch silicon wafer to obtain a clean silicon wafer for standby use;

[0035] Step 2: Place the clean silicon wafer obtained in step 1 on the sample stage of the magnetron sputtering equipment, and first evacuate the vacuum degree of the magnetron sputtering equipment to 9×10 -4Pa, then introduce working gas to make the working gas pressure of the magnetron sputtering equipment to 0.5Pa, and set the sputtering power of the magnetron sputtering equipment to 60W, the sputtering time to 30 minutes, the sample stage temperature to room temperature, the sample stage speed to 20rpm, use WO3 with a mass purity of 99.99% as the target material ((tied with a copper back target with a thickness of 2mm)), turn on the magnetron sputtering equipment to sputter WO3 to the clean silicon wafer on the sample stage, and form an amorphous tungsten trioxide film with a thickness of 280nm on the surface of the clean silicon wafer, and obtain a silicon wafer with an amorphous tungsten trioxide film on the surface;

[0036] Step 3, immersing the silicon wafer with the amorphous tungsten trioxide film on the surface obtained in step 2 in a 0.5 mol / L hydrochloric acid (HCl) solution for 12 hours, taking it out and drying it, at which time the amorphous tungsten trioxide film undergoes a hydration reaction to form a hydrated WO3 nanosheet porous film, thereby obtaining a silicon wafer with a hydrated WO3 nanosheet porous film;

[0037] Step 4, placing the silicon wafer with the hydrated WO3 nanosheet porous film obtained in step 3 in air, and annealing it at 400° C. for 2 hours, at which time the hydrated WO3 nanosheet porous film forms a tungsten trioxide nanosheet hydrogen sensing layer material;

[0038] In this embodiment, in step 1, the thickness of the double-sided polished four-inch silicon wafer is 380um, and the specific process of cleaning and drying the double-sided polished four-inch silicon wafer is: ultrasonic cleaning in acetone solution for 10 minutes, ultrasonic cleaning in anhydrous ethanol for 10 minutes, and finally cleaning with deionized water and drying.

[0039] In this embodiment, in step 2, the working gas is a mixed gas of argon (Ar) with a mass purity of 99.99% and oxygen (O2) with a mass purity of 99.99%.

[0040] In this embodiment, in step 2, when the working gas is introduced, the gas flow rate of Ar is 40 sccm and the gas flow rate of O2 is 4 sccm.

[0041] In this example, the surface morphology of the amorphous tungsten trioxide film obtained is as follows Figure 1 Its XRD pattern is shown in Figure 2 a; the surface morphology of the obtained hydrated WO3 nanosheet porous film is as shown in Figure 3 Its XRD pattern is shown in Figure 2 As shown in b; the surface morphology of the obtained tungsten trioxide nanosheet hydrogen sensing layer material is as follows Figure 4 Its XRD and Raman spectra are shown in Figure 2 c and Figure 5 shown.

[0042] analyze Figure 1It can be seen that the amorphous tungsten trioxide film just after sputtering is dense.

[0043] analyze Figure 2 a It can be seen that the amorphous tungsten trioxide film just after sputtering is amorphous.

[0044] analyze Figure 3 It can be seen that the sputtered amorphous tungsten trioxide film becomes a nanosheet structure after being etched by hydrochloric acid.

[0045] analyze Figure 2 b It can be seen that the amorphous tungsten trioxide film after sputtering becomes a hydrated WO3 crystal structure after being etched by hydrochloric acid.

[0046] analyze Figure 4 It can be seen that the nanostructure of the porous film of hydrated WO3 nanosheets remains consistent after annealing in air. Figure 2 c It can be seen that the crystal structure of the hydrated WO3 nanosheet porous film after annealing in air becomes a monoclinic phase.

[0047] analyze Figure 5 It can be seen that in the Raman spectrum, the -1 The two peaks at 270.80 and 322.16 cm-1 belong to the stretching mode υ(OWO) of adjacent oxygen atoms. -1 The peak is related to the bending mode δ(OWO), which confirms that the hydrogen sensing layer material of the tungsten trioxide nanosheets we finally obtained is indeed WO3.

[0048] Example 2: This example is basically the same as Example 1, except that: in this example, the magnetron sputtering time is 20 minutes, and the surface morphology of the tungsten trioxide nanosheet hydrogen sensing layer material is as follows: Figure 6 shown.

[0049] analyze Figure 6 It can be seen that the tungsten trioxide nanosheet hydrogen sensing layer material obtained under the conditions of Example 2 has rich nanostructures and specific crystal phases.

[0050] Example 3: This example is basically the same as Example 1, except that: in this example, the gas flow rate of O2 is 12sccm, and the surface morphology of the hydrogen sensing layer material of the tungsten trioxide nanosheet is as follows: Figure 7 shown.

[0051] analyze Figure 7 It can be seen that the tungsten trioxide nanosheet hydrogen sensing layer material obtained under the conditions of Example 3 has rich nanostructures and specific crystal phases.

[0052] Example 4: This example is basically the same as Example 1, except that: in this example, the gas flow rate of O2 is 20sccm, and the surface morphology of the hydrogen sensing layer material of the tungsten trioxide nanosheet is as follows: Figure 8 shown.

[0053] analyze Figure 8 It can be seen that the tungsten trioxide nanosheet hydrogen sensing layer material obtained under the conditions of Example 4 has rich nanostructures and specific crystal phases.

[0054] In order to verify the effectiveness of the tungsten trioxide nanosheet hydrogen sensor layer material prepared by the wafer-level preparation method of the tungsten trioxide nanosheet hydrogen sensor layer material of the present invention on the hydrogen sensor, a hydrogen sensor is prepared based on the wafer-level preparation method of the tungsten trioxide nanosheet hydrogen sensor layer material of the present invention, as shown in Example 5.

[0055] Embodiment 5: The specific process of preparing a hydrogen sensor based on the wafer-level preparation method of the tungsten trioxide nanosheet hydrogen sensing layer material of the present invention is as follows:

[0056] Step S1, using a double-sided polished four-inch silicon wafer as a substrate, and performing surface treatment on the double-sided polished four-inch silicon wafer, the specific process is: ultrasonic cleaning in an acetone solution for 10 minutes, ultrasonic cleaning in anhydrous ethanol for 10 minutes, and finally cleaning with deionized water and drying to obtain a clean silicon wafer;

[0057] Step S2, using a photolithography process to process the clean silicon wafer, forming a predetermined interdigital electrode pattern of a hydrogen sensor on the clean silicon wafer, and obtaining a silicon wafer having a predetermined interdigital electrode pattern on the surface;

[0058] Step S3, first using an evaporation apparatus to sequentially evaporate chromium and gold onto the surface of a silicon wafer having a predetermined interdigital electrode pattern to obtain a chromium / gold film with a thickness of 40 to 50 nm, and then placing the film in acetone to strip off the remaining photoresist in the photolithography process to obtain a silicon wafer having chromium / gold interdigital electrodes on the surface;

[0059] Step S4, the silicon wafer with the chromium / gold interdigital electrodes on the surface is treated again by photolithography process, and a predetermined sensing layer pattern of the hydrogen sensor is formed on the surface of the silicon wafer with the chromium / gold interdigital electrodes on the surface, so as to obtain a silicon wafer with a predetermined sensing layer pattern on the surface;

[0060] Step S5, placing the silicon wafer with the predetermined sensing layer pattern on the surface on the sample stage of the magnetron sputtering equipment, using WO3 with a mass purity of 99.99% as the target material (with a copper back target with a thickness of 2mm), argon with a mass purity of 99.999% and oxygen with a mass purity of 99.999% as the working gas, and the specific steps of magnetron sputtering are as follows: first, the vacuum degree of the magnetron sputtering equipment is pumped to less than 9×10 -4Pa, then introduce working gas, wherein the argon flow rate is 40sccm, the oxygen flow rate is 4sccm, the working gas pressure of the magnetron sputtering equipment is set to 0.5Pa, and set the DC sputtering power of the magnetron sputtering equipment to 60W, the sputtering time to 20 minutes, the sample stage temperature to room temperature, and the sample stage speed to 20rpm. Turn on the magnetron sputtering equipment to sputter WO3 onto the surface of the silicon wafer with a predetermined sensing layer pattern on the sample stage, and form an amorphous WO3 film with a thickness of 220nm on the surface of the silicon wafer with a predetermined sensing layer pattern on the surface, so as to obtain a silicon wafer with an amorphous WO3 film on the surface;

[0061] Step S6, placing the silicon wafer with the amorphous WO3 film on the surface in the vacuum chamber of the magnetron sputtering equipment, using palladium with a mass purity of 99.99% as the target material, and argon with a mass purity of 99.999% as the working gas. The specific steps of magnetron sputtering are: evacuating the vacuum degree to 3×10 -3 Pa, then introduce working gas, wherein the argon flow rate is 20sccm, make the working gas pressure of the magnetron sputtering equipment to 0.5Pa, the sputtering power is 40W, the sputtering time is 20 seconds, the sample stage temperature is room temperature, and the sample stage speed is 40rpm. A layer of palladium is sputtered on the surface of the silicon wafer with an amorphous WO3 film on the surface to obtain a silicon wafer with a palladium-loaded amorphous WO3 film on the surface (surface pattern as shown in Fig. 9 shown);

[0062] Step S7, then, placing it in acetone to strip off the remaining photoresist in the photolithography process, to obtain a silicon wafer with a patterned palladium-loaded amorphous WO3 film on the surface;

[0063] Step S8, after etching the silicon wafer with the patterned palladium-loaded amorphous WO3 film on the surface in a 0.5 mol / L hydrochloric acid solution for 12 hours, take it out and dry it to obtain a silicon wafer with a palladium-loaded hydrated WO3 nanosheet porous film. Finally, anneal the silicon wafer with the palladium-loaded hydrated WO3 nanosheet porous film in air at 400°C for 2 hours to obtain a wafer-level palladium-loaded WO3 nanosheet hydrogen sensor (its structure is as shown in FIG. Fig.10 The morphology of the palladium-loaded WO3 nanosheets on the surface of the hydrogen sensor is as follows: Fig.11 As shown, the optical image of a single hydrogen sensor is Fig.12 The hydrogen sensor was placed in 1000ppm hydrogen to test its hydrogen sensitivity. The hydrogen sensitivity test graphs and response curves measured at different temperatures are shown in Figure 1. Fig.13 and Fig.14 shown.

[0064] analyze Fig. 9 It can be seen that the surface of the amorphous WO3 film just after sputtering Pd is dense, but there are some tiny protrusions.

[0065] analyze Fig.10 It can be seen that we have successfully prepared a wafer-level palladium-loaded WO3 nanosheet hydrogen sensor.

[0066] analyze Fig.11 It can be seen that the tungsten trioxide nanosheet hydrogen sensing layer material of the hydrogen sensor finally obtained has a rich nanosheet structure.

[0067] analyze Fig.12 It can be seen that the single hydrogen sensor we prepared is very small, much smaller than a grain of rice.

[0068] analyze Fig.13 It can be seen that the hydrogen sensor we prepared shows ultra-high response to 1000ppm hydrogen at different temperatures.

[0069] analyze Fig.14 It can be seen that the hydrogen sensor we prepared has the fastest response and recovery time (5.3 / 87.6 seconds) at 200°C.

[0070] In summary, the wafer-level preparation method of the tungsten trioxide nanosheet hydrogen sensing layer material of the present invention has easy control of process conditions, good result repeatability, and can realize large-scale and uniform production of tungsten trioxide nanosheet hydrogen sensing layer materials with rich nanostructures, high chemical purity and specific crystal phases, and can realize wafer-level preparation. When the tungsten trioxide nanosheet hydrogen sensing layer material prepared by the method of the present invention is used in a hydrogen sensor, when the concentration of H2 is 1000ppm, its sensitivity reaches 1.41x10 4 , the response-recovery time reaches 5.3 seconds and 87.6 seconds respectively, which can significantly improve the high sensitivity of the hydrogen sensor to hydrogen. The wafer-level preparation method of the tungsten trioxide nanosheet hydrogen sensing layer material of the present invention has broad application prospects and significance in the field of high-sensitivity hydrogen sensor preparation.

Claims

1. A wafer-level preparation method for a tungsten trioxide nanosheet hydrogen sensing layer material, characterized in that The following steps are involved: Step 1, cleaning and drying a double-sided polished four-inch silicon wafer to obtain a clean silicon wafer for standby use; Step 2: Place the clean silicon wafer obtained in step 1 on the sample table of the magnetron sputtering equipment, and first evacuate the vacuum degree of the magnetron sputtering equipment to no more than 9×10 -4 Pa, then introduce working gas to make the working gas pressure of the magnetron sputtering equipment to 0.4-0.7Pa, and set the sputtering power of the magnetron sputtering equipment to 40-75W, the sputtering time to 20-40 minutes, the sample stage temperature to room temperature, the sample stage speed to 20-40rpm, use WO3 with a mass purity of not less than 99.99% as the target material, start the magnetron sputtering equipment to sputter WO3 to the clean silicon wafer on the sample stage, and form an amorphous tungsten trioxide film with a thickness of 200nm to 400nm on the surface of the clean silicon wafer, and obtain a silicon wafer with an amorphous tungsten trioxide film on the surface; Step 3, immersing the silicon wafer with the amorphous tungsten trioxide film on the surface obtained in step 2 in a 0.1-0.5 mol / L hydrochloric acid (HCl) solution for 10-24 hours, then taking it out and drying it, at which time the amorphous tungsten trioxide film undergoes a hydration reaction to form a hydrated WO3 nanosheet porous film, thereby obtaining a silicon wafer with a hydrated WO3 nanosheet porous film; Step 4: Place the silicon wafer with the hydrated WO3 nanosheet porous film obtained in step 3 in the air and anneal it at 350-450°C for 2-3 hours, at which time the hydrated WO3 nanosheet porous film forms a tungsten trioxide nanosheet hydrogen sensing layer material.

2. The wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material according to claim 1, characterized in that In the step 1, the thickness of the double-sided polished four-inch silicon wafer is 380um, and the specific process of cleaning and drying the double-sided polished four-inch silicon wafer is: ultrasonic cleaning in acetone solution for 5-10 minutes, ultrasonic cleaning in anhydrous ethanol for 5-10 minutes, and finally cleaning with deionized water and drying.

3. The wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material according to claim 1, characterized in that In the step 2, the working gas is a mixed gas of argon (Ar) with a mass purity of not less than 99.99% and oxygen (O2) with a mass purity of not less than 99.99%.

4. The wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material according to claim 1, characterized in that In the step 2, when the working gas is introduced, the gas flow rate of Ar is 20-60 sccm, and the gas flow rate of O2 is 4-20 sccm.

5. The wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material according to claim 4, characterized in that In the step 2, when the working gas is introduced, the gas flow rate of Ar is 40 sccm and the gas flow rate of O2 is 4 sccm.

6. The wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material according to claim 4, characterized in that In the step 2, when the working gas is introduced, the gas flow rate of Ar is 40 sccm and the gas flow rate of O2 is 12 sccm.

7. The wafer-level preparation method of a tungsten trioxide nanosheet hydrogen sensing layer material according to claim 4, characterized in that In the step 2, when the working gas is introduced, the gas flow rate of Ar is 40 sccm and the gas flow rate of O2 is 20 sccm.

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