Hydrogen sensor with ultrafast hydrogen response speed and preparation method thereof

Abstract

The invention provides a hydrogen sensor with an ultrafast hydrogen response speed and a preparation method thereof, the hydrogen sensor comprises a silicon oxide substrate and a double-interdigital electrode structure, the double-interdigital electrode structure comprises a titanium electrode layer, a tungsten enhancement layer and a palladium sensitive layer; an interdigital electrode pattern is arranged on the silicon oxide substrate, the titanium electrode layer covers the interdigital electrode pattern, the tungsten enhancement layer covers a pin area and a bridge arm resistance area of a titanium electrode, the palladium sensitive layer covers the titanium electrode layer and corresponds to the position of the interdigital electrode pattern, and the titanium electrode layer is directly arranged on the silicon oxide substrate. The structure is simple, the titanium electrode serves as the bottom electrode, the sensitivity and mechanical stability of the sensor are improved, the tungsten enhancement layers are arranged in the titanium electrode pin area and the bridge arm resistor area, and the overall conductivity and mechanical strength are improved.

Description

Technical Field

[0001] This invention relates to the field of gas sensor technology, and in particular to a hydrogen sensor with an ultrafast hydrogen response speed and its preparation method. Background Technology

[0002] Hydrogen, as a clean energy source, has broad application prospects in energy storage, fuel cells, and chemical production. However, hydrogen is flammable and explosive, with a wide explosion limit range in air (4.0% - 75.6%), making real-time, rapid, and accurate detection crucial. Traditional hydrogen sensors suffer from slow response times, low sensitivity, and poor stability, making it difficult to meet the demands for rapid hydrogen detection in practical applications. For example, some electrochemically based hydrogen sensors typically have response times of several seconds or even tens of seconds, failing to detect hydrogen leaks in a timely manner and posing significant safety hazards in scenarios with extremely high safety requirements. Furthermore, existing sensors are complex to manufacture and costly, hindering large-scale production and application. Therefore, developing a hydrogen sensor with fast response times, high sensitivity, and a simple manufacturing process is of significant practical importance.

[0003] Chinese patent application No. 202410285972.3, published on July 26, 2024, discloses a method for fabricating a hydrogen sensor based on nickel oxide quantum dot material. The method includes: providing a substrate; forming an insulating layer on the substrate; patterning the insulating layer to obtain a pre-suspended film structure; forming a seed layer on the insulating layer; photolithographically overlaying electrode patterns on the seed layer; forming an electrode layer with a Wheatstone bridge pattern on the surface of the seed layer; annealing after resist washing; removing excess seed layer and part of the substrate to form a MEMS micro-heating plate with a suspended film structure and Wheatstone bridge structure electrodes; and drop-coating a hydrogen-sensitive material slurry onto the hydrogen-sensitive region of the electrode layer to form a hydrogen-sensitive layer. The hydrogen-sensitive material slurry is prepared by adding nickel oxide quantum dots and palladium-tungsten particles to a mixed solution of α-terpineol, isopropanol, and PEG-300 and stirring.

[0004] The hydrogen sensor first forms an insulating layer on a substrate, then forms a seed layer on the insulating layer, and then photolithographically overlays electrode patterns on the seed layer. This structure is complex and has high manufacturing costs. At the same time, the sensor has low mechanical strength and is prone to damage. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a hydrogen sensor with an ultrafast hydrogen response speed and its preparation method. A titanium electrode layer is directly disposed on a silicon oxide substrate, which has a simple structure. The titanium electrode is used as the bottom electrode to improve the sensitivity and mechanical stability of the sensor. A tungsten reinforcement layer is disposed in the titanium electrode pin area and the bridge arm resistance area to improve the overall conductivity and mechanical strength.

[0006] To solve the above-mentioned technical problems, the technical solution used in this invention is as follows: The present invention discloses an ultrafast hydrogen response hydrogen sensor, comprising a silicon oxide substrate and a bifid electrode structure, wherein the bifid electrode structure comprises a titanium electrode layer, a tungsten reinforcement layer and a palladium sensitive layer; a bifid electrode pattern is provided on the silicon oxide substrate, the titanium electrode layer covers the bifid electrode pattern, the tungsten reinforcement layer covers the pin area and bridge arm resistance area of ​​the titanium electrode, and the palladium sensitive layer covers the titanium electrode layer and corresponds to the position of the bifid electrode pattern.

[0007] Preferably, the thickness of the titanium electrode layer is 8-12 nm, the thickness of the tungsten reinforcement layer is 13-17 nm, and the thickness of the palladium sensitive layer is 11-15 nm.

[0008] Preferably, the titanium electrode layer is provided with a Wheatstone bridge circuit, which includes a palladium film sensitive resistor R1, a palladium film sensitive resistor R2, a reference resistor R3, and a reference resistor R4; the palladium film sensitive resistor R1 and the reference resistor R4 are diagonally arranged and connected to the bridge input terminal, and the palladium film sensitive resistor R2 and the reference resistor R3 are diagonally arranged and connected to the bridge input terminal.

[0009] Preferably, the interdigitated electrode pattern has ten pairs of interdigitated fingers, with a finger width of 180-220μm, a finger spacing of 30-60μm, and a sensitive area of ​​7000μm×5500μm.

[0010] Another object of the present invention is to provide a method for fabricating a hydrogen sensor with an ultrafast hydrogen response rate, comprising the following steps: S1. Pretreatment of the silicon oxide substrate; S2. Photolithographically pattern interdigitated electrode patterns on the pretreated silicon oxide substrate; S3. Deposit a titanium electrode layer on the interdigitated electrode pattern; S4. Deposit a tungsten reinforcement layer in the lead region and bridge arm resistance region of the titanium electrode layer; S5. Remove the metal film above the unexposed photoresist on the silicon oxide substrate; S6. Deposit a palladium sensitive layer at the corresponding positions of the titanium electrode layer and tungsten reinforcement layer and the interdigitated electrode pattern.

[0011] Preferably, S1 specifically involves ultrasonically cleaning the silicon oxide substrate in acetone, ethanol, and deionized water in sequence, followed by drying.

[0012] Preferably, S3 specifically involves depositing a titanium electrode layer on the interdigitated electrode pattern using an electron beam evaporation titanium target, with the deposition thickness of the titanium electrode layer being 8~12nm.

[0013] Preferably, S4 specifically involves depositing a tungsten reinforcement layer in the pin region and bridge arm resistance region of the titanium electrode layer by electron beam evaporation of a tungsten target, with the deposition thickness of the tungsten reinforcement layer being 13~17nm.

[0014] Preferably, S6 specifically involves depositing a palladium sensitive layer at the corresponding positions of the titanium electrode layer and the tungsten reinforcement layer and the interdigitated electrode pattern using an electron beam evaporation palladium target, with the palladium sensitive layer having a deposition thickness of 11~15nm.

[0015] Preferably, step S5 involves immersing the silicon oxide substrate in a photoresist remover solution to peel off the metal layer above the unexposed photoresist from the surface of the silicon oxide substrate, and then rinsing the surface of the silicon oxide substrate clean.

[0016] Compared with existing technologies, the advantages of the hydrogen sensor with ultrafast hydrogen response speed described in this invention are mainly reflected in: The titanium electrode layer is directly disposed on the silicon oxide substrate, resulting in a simple structure. Furthermore, titanium electrodes exhibit excellent conductivity, strong adhesion to the silicon oxide substrate, and strong hydrogen adsorption capacity. Using the titanium electrode as the bottom electrode enhances the sensor's sensitivity and mechanical stability. A tungsten reinforcement layer improves the conductivity and mechanical strength of the titanium electrode's pin area and bridge arm resistance area. A palladium sensitive layer is incorporated; the rapid lattice expansion and transient electronic structure changes during the reversible adsorption of hydrogen atoms allow for an immediate response upon contact with hydrogen, enabling rapid detection of hydrogen concentration.

[0017] By limiting the thickness of the tungsten reinforcement layer, the total resistance of the sensor is kept within the reasonable range for hydrogen-sensitive signal acquisition, without causing current shunting to the change in resistance of the palladium film sensitive resistor. Simultaneously, it possesses good conductivity, and this thickness provides good mechanical strength to the pins, preventing damage to the titanium electrode pin area due to use. Limiting the thickness of the palladium sensitive layer improves the sensor's response speed, responsivity, and stability.

[0018] In the Wheatstone bridge circuit, a palladium film sensitive resistor is used as the working arm, and a reference resistor is used as the compensation arm, forming a four-arm bridge circuit. When affected by environmental factors (temperature fluctuations, humidity fluctuations), the resistances of the working arm and the compensation arm change in the same direction and amplitude due to the symmetry of their physical characteristics, and the bridge maintains a balanced state. However, when hydrogen gas acts on the palladium film sensitive resistor, the working arm changes its resistance due to the adsorption of hydrogen atoms, while the compensation arm is unaffected. The bridge becomes unbalanced and outputs a differential signal, which cancels out the common offset caused by environmental factors. In this way, only the specific resistance change caused by hydrogen gas is retained, thereby effectively suppressing zero-point drift.

[0019] By limiting the structural parameters of the interdigital electrode pattern, the shape and size of the titanium electrode formed on the interdigital electrode pattern can be restricted. The setting of these parameters can improve the sensitivity and response speed of the sensor.

[0020] By combining a titanium electrode layer, a tungsten reinforcement layer, a palladium sensitive layer, and a Wheatstone bridge circuit, the response speed of the hydrogen sensor is significantly improved, enabling timely detection of hydrogen leaks and enhancing safety; the hydrogen sensor's response time at a 1% hydrogen concentration is less than 0.5 seconds.

[0021] Compared with existing technologies, the advantages of the method for preparing an ultrafast hydrogen response hydrogen sensor described in this invention are mainly reflected in: Depositing titanium electrode layers directly on the interdigitated electrode pattern simplifies the fabrication process while ensuring sensor sensitivity and mechanical stability. Removing unwanted metal films by stripping the unexposed photoresist film from the silicon oxide substrate results in a clearer interdigitated electrode pattern. Pre-treatment of the silicon oxide substrate removes impurities and contaminants from its surface, simplifying the process by using only acetone, ethanol, and deionized water. Controlling the deposition thickness of the tungsten reinforcement layer provides better mechanical strength to the pins while improving deposition efficiency. Controlling the thickness of the palladium sensitive layer improves the response speed, responsivity, and stability of the hydrogen sensor. Matching the thicknesses of the titanium electrode layer and the palladium sensitive layer ensures high-quality deposition of the sensitive layer. Immersing the silicon oxide substrate in a stripping solution rapidly removes the unexposed photoresist film from the silicon oxide substrate.

[0022] This invention directly sets a titanium electrode layer on a silicon oxide substrate, resulting in a simple structure. Using the titanium electrode as the bottom electrode improves the sensitivity and mechanical stability of the sensor. A tungsten reinforcement layer is set in the titanium electrode pin area and the bridge arm resistance area to improve the overall conductivity and mechanical strength. Attached Figure Description

[0023] The above and other objects, features, and advantages of the invention will become clearer through a more detailed description of the preferred embodiments illustrated in the accompanying drawings. The same reference numerals denote the same parts throughout the drawings, and the drawings are not intentionally drawn to scale with actual dimensions; the focus is on illustrating the gist of the invention.

[0024] Figure 1 This is a classification diagram of the hydrogen sensor of the present invention.

[0025] Figure 2 This is a schematic diagram of the hydrogen sensor of the present invention.

[0026] Figure 3 This is a cross-sectional view of the hydrogen sensor of the present invention.

[0027] Figure 4 This is a circuit diagram of the Wheatstone bridge circuit in the hydrogen sensor of the present invention.

[0028] Figure 5aThis is a cyclic test performance curve of the hydrogen sensor of the present invention at 65°C, representing the response / recovery time.

[0029] Figure 5b yes Figure 5a A magnified image from 0-5 seconds.

[0030] Figure 6a This is a graph showing the response / recovery time of the hydrogen sensor of the present invention at different temperatures.

[0031] Figure 6b yes Figure 6a A magnified image from 0-5 seconds.

[0032] Explanation of reference numerals: 1. Silicon oxide substrate; 2. Titanium electrode layer; 3. Tungsten reinforcement layer; 4. Palladium sensitive layer; 5. Silicon bottom layer. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention. In this embodiment, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0034] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to and integrated with the other element, or there may be an intervening element present. The terms "mounted," "one end," "the other end," and similar expressions used in this invention are for illustrative purposes only.

[0035] like Figure 1-6b As shown, a hydrogen sensor with ultrafast hydrogen response speed includes a silicon oxide substrate 1 and a bifid electrode structure. The bifid electrode structure includes a titanium electrode layer 2, a tungsten reinforcement layer 3, and a palladium sensitive layer 4. The bifid electrode pattern is provided on the silicon oxide substrate 1. The titanium electrode layer 2 covers the bifid electrode pattern. The tungsten reinforcement layer 3 covers the pin area and bridge arm resistance area of ​​the titanium electrode. The palladium sensitive layer 4 covers the titanium electrode layer 2 and corresponds to the position of the bifid electrode pattern.

[0036] The titanium electrode layer 2 is directly disposed on the silicon oxide substrate 1, resulting in a simple structure. Furthermore, the titanium electrode exhibits good conductivity, strong adhesion to the silicon oxide substrate 1, and strong hydrogen adsorption capacity. Using the titanium electrode as the bottom electrode enhances the sensor's sensitivity and mechanical stability. A tungsten reinforcement layer 3 improves the conductivity and mechanical strength of the titanium electrode pin area and bridge arm resistance area. A palladium sensitive layer 4 is incorporated; when palladium undergoes reversible adsorption with hydrogen atoms, the lattice expands rapidly, and the electronic structure changes transiently, enabling an immediate response upon contact with hydrogen, thus allowing for rapid detection of hydrogen concentration.

[0037] The thickness of the titanium electrode layer 2 is 8-12 nm, the thickness of the tungsten reinforcement layer 3 is 13-17 nm, and the thickness of the palladium sensitive layer 4 is 11-15 nm. By limiting the thickness of the tungsten reinforcement layer 3, the total resistance of the sensor is controlled, ensuring that the total resistance of the sensor is within the rational range for hydrogen-sensitive signal acquisition and does not shunt the change in resistance of the palladium film sensitive resistor. This avoids the situation where the total resistance of the sensor is too high, resulting in insufficient current in the circuit, weak signal strength, and easy masking of the signal by noise, thus leading to a decrease in detection accuracy. At the same time, it also avoids the situation where the total resistance of the sensor is too low, resulting in excessive current exceeding the circuit range, causing the sensor to overheat and affecting the hydrogen adsorption characteristics of the palladium sensitive layer 4. Conversely, it also avoids the situation where the total resistance of the sensor is too low, resulting in excessive current and excessive power consumption, which would also cause the sensor to overheat and affect the hydrogen adsorption characteristics of the palladium sensitive layer 4.

[0038] The tungsten reinforcement layer 3, with a thickness of 13-17 nm, exhibits good electrical conductivity and Brinell hardness, providing good mechanical strength to the leads and preventing damage or wear to the titanium electrode's lead area during use. In a preferred embodiment, a probe station is used to test the hydrogen sensor, with the tungsten reinforcement layer 3 covering the lead area of ​​the titanium electrode, protecting it from probe wear.

[0039] By limiting the thickness of the palladium sensitive layer 4, the sensor's response speed, responsivity, and stability are improved. By controlling the thickness of the titanium electrode layer 2 in conjunction with the thickness of the palladium sensitive layer 4, the deposition quality of the sensitive layer is ensured.

[0040] In a preferred embodiment, the titanium electrode layer 2 has a thickness of 10 nm, the tungsten reinforcement layer 3 has a thickness of 15 nm, and the palladium sensing layer 4 has a thickness of 13 nm. Due to the overall thickness limitation of the hydrogen sensor, a palladium sensing layer 4 with a thickness of 13 nm is provided to ensure that the thickness of the palladium sensing layer 4 is greater than the thickness of the titanium electrode layer 2; at the same time, it avoids the palladium sensing layer 4 being too thick, which could cause it to expand and crack when absorbing hydrogen, resulting in the resistance failing to return to the reference value.

[0041] The titanium electrode layer 2 is provided with a Wheatstone bridge circuit, which includes a palladium film sensitive resistor R1, a palladium film sensitive resistor R2, a reference resistor R3, and a reference resistor R4; the palladium film sensitive resistor R1 and the reference resistor R4 are diagonally arranged and connected to the bridge input terminal, and the palladium film sensitive resistor R2 and the reference resistor R3 are diagonally arranged and connected to the bridge input terminal.

[0042] In the Wheatstone bridge circuit, a palladium film sensitive resistor is used as the working arm, and a reference resistor is used as the compensation arm, forming a four-arm bridge circuit. When affected by environmental factors, such as temperature and humidity fluctuations, the resistances of the working arm and the compensation arm change in the same direction and amplitude due to the symmetry of their physical characteristics, and the bridge maintains a balanced state. However, when hydrogen gas acts on the palladium film sensitive resistor, the working arm changes resistance due to the adsorption of hydrogen atoms, while the compensation arm is unaffected. The bridge becomes unbalanced and outputs a differential signal, which cancels out the common offset caused by environmental factors. In this way, only the specific resistance change caused by hydrogen gas is retained, thereby effectively suppressing zero-point drift.

[0043] Reference Figure 2 As shown, without hydrogen gas, the bridge is in equilibrium, and the resistances of the palladium film sensitive resistor R1 and reference resistor R4 are equal to the resistances of the palladium film sensitive resistor R2 and reference resistor R3, i.e., R1R4 = R2R3, and the bridge output voltage Uout = 0. When hydrogen gas is introduced and applied to the palladium film sensitive resistor, its resistance changes. At this point, R1R4 ≠ R2R3, the bridge balance is broken, and the bridge will have a voltage output Uout.

[0044] The interdigitated electrode pattern has ten pairs of interdigitated fingers, with a finger width of 180-220 μm, a finger spacing of 30-60 μm, and a sensitive area of ​​7000 μm × 5500 μm. In a preferred embodiment, the interdigitated electrode pattern has ten pairs of interdigitated fingers, with a finger width of 200 μm, a finger spacing of 50 μm, and a sensitive area of ​​7000 μm × 5500 μm. By defining the structural parameters of the interdigitated electrode pattern, the shape and size of the titanium electrode formed on the interdigitated electrode pattern are limited. The setting of these parameters can improve the sensitivity and response speed of the sensor.

[0045] In this embodiment, a silicon underlayer 5 is provided at the bottom of the silicon oxide substrate 1; the silicon underlayer is thermally oxidized into silicon dioxide through a thermal oxidation process to form the silicon oxide substrate 1.

[0046] Reference Figure 5a and Figure 5b As shown, during cyclic testing at 65°C, the output parameters of the hydrogen sensor reached 90% of their stable value within 1 second; (Refer to...) Figure 6a and Figure 6bAs shown, at temperatures of 45℃, 55℃, 65℃, 75℃, 85℃, and 90℃, the response time of the hydrogen sensor at a 1% hydrogen concentration is within 1 second. Preferably, at temperatures between 75℃ and 115℃, the response time of the hydrogen sensor is even shorter, less than 0.5 seconds. The response time is the time required for the hydrogen sensor output parameter to reach 90% of its stable value after contact with hydrogen.

[0047] This invention significantly improves the response speed of a hydrogen sensor by combining a titanium electrode layer 2, a tungsten reinforcement layer 3, a palladium sensitive layer 4, and a Wheatstone bridge circuit, enabling timely detection of hydrogen leaks and enhancing safety; the hydrogen sensor's response time at a 1% hydrogen concentration is less than 0.5 seconds.

[0048] A method for fabricating a hydrogen sensor with ultrafast hydrogen response speed includes the following steps: S1. Pretreatment of the silicon oxide substrate 1: Specifically, the silicon oxide substrate 1 is sequentially immersed in acetone, ethanol, and deionized water for ultrasonic cleaning, and then dried. Preferably, the silicon oxide substrate 1 is cleaned in acetone, ethanol, and deionized water for 15 minutes and then dried using nitrogen gas.

[0049] S2. Photolithographically pattern interdigitated electrode patterns on the pretreated silicon oxide substrate 1; preferably, preset sensor size parameters, use a photolithography machine to expose the pattern on the silicon oxide substrate, and then remove the photoresist in the exposed area through a development process to obtain the interdigitated electrode pattern.

[0050] S3. Deposit a titanium electrode layer 2 on the interdigitated electrode pattern; specifically, deposit the titanium electrode layer 2 on the interdigitated electrode pattern using an electron beam evaporation titanium target, with a deposition thickness of 8~12 nm. Preferably, the silicon oxide substrate 1 is placed in an electron beam evaporation apparatus, and the vacuum level is evaporated to 3.8 × 10⁻⁶. -3 Below Pa, the base disk rotation speed is set to 8 r / min, and a titanium electrode layer 2 with a thickness of 10 nm is deposited by electron beam evaporation of the titanium target.

[0051] S4. Deposit a tungsten reinforcement layer 3 in the lead region and bridge arm resistance region of the titanium electrode layer 2; specifically, deposit the tungsten reinforcement layer 3 in the lead region and bridge arm resistance region of the titanium electrode layer 2 by electron beam evaporation of a tungsten target, and the deposition thickness of the tungsten reinforcement layer 3 is 13~17nm. Preferably, while maintaining the same vacuum level and substrate rotation speed during the deposition of the titanium electrode layer 2, the tungsten target is replaced, and a tungsten reinforcement layer 3 with a thickness of 15nm is deposited.

[0052] S5. Strip the metal film above the unexposed photoresist on the silicon oxide substrate 1; specifically, immerse the silicon oxide substrate 1 in a stripping solution to peel off the metal film above the unexposed photoresist from the surface of the silicon oxide substrate 1, and then rinse the surface of the silicon oxide substrate 1 clean. Preferably, the stripping solution is an NMP stripping solution, and the silicon oxide substrate 1 is immersed in the NMP stripping solution for 5 minutes; then the silicon oxide substrate 1 is rinsed with deionized water.

[0053] S6. Deposit a palladium-sensitive layer 4 at the corresponding positions of the titanium electrode layer 2 and the tungsten reinforcement layer 3 with the interdigitated electrode pattern; specifically, deposit the palladium-sensitive layer 4 at the corresponding positions of the titanium electrode layer 2 and the tungsten reinforcement layer 3 with the interdigitated electrode pattern using an electron beam evaporation target. The deposition thickness of the palladium-sensitive layer 4 is 11~15nm. Preferably, after depositing the tungsten reinforcement layer 3, the silicon oxide substrate 1 is placed with a metal mask and then placed in an electron beam evaporation apparatus, and the vacuum degree is evaporated to 3.8×10⁻⁶. -3 With a Pa level below 8, the base plate rotation speed is set to 8 r / min, and a palladium sensitive layer with a thickness of 13 nm is deposited by evaporating the palladium target with an electron beam.

[0054] The above method directly deposits the titanium electrode layer 2 on the interdigital electrode pattern, simplifying the fabrication process while ensuring the sensor's sensitivity and mechanical stability. By stripping the metal film above the unexposed photoresist on the silicon oxide substrate, unwanted metal films are removed, making the interdigital electrode pattern clearer. Impurities and contaminants on the surface of the silicon oxide substrate 1 are removed during pretreatment, and the use of only acetone, ethanol, and deionized water simplifies the pretreatment process. By controlling the deposition thickness of the tungsten reinforcement layer 3, better mechanical strength is provided to the pins while improving evaporation efficiency. By controlling the thickness of the palladium sensitive layer 4, the response speed, responsivity, and stability of the hydrogen sensor are improved. By controlling the thickness of the titanium electrode layer 2 in conjunction with the thickness of the palladium sensitive layer 4, the deposition quality of the sensitive layer is ensured. Immersing the silicon oxide substrate 1 in a stripping solution allows for the rapid removal of the metal film above the unexposed photoresist on the silicon oxide substrate. The combination of titanium electrode layer 2, tungsten reinforcement layer 3, palladium sensitive layer 4 and Wheatstone bridge circuit significantly improves the response speed of hydrogen sensor, enabling timely detection of hydrogen leaks and improving safety; the hydrogen sensor's response time at a 1% hydrogen concentration is less than 0.5s.

[0055] In this specification, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0056] In the description of this specification, the references to terms such as "preferred embodiment," "another embodiment," "other embodiment," or "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A hydrogen sensor with ultrafast hydrogen response speed, characterized in that: The application relates to a silicon oxide substrate and a double-fork electrode structure, the double-fork electrode structure comprising a titanium electrode layer, a tungsten reinforcing layer and a palladium sensitive layer; an interdigital electrode pattern is arranged on the silicon oxide substrate, the titanium electrode layer covers the interdigital electrode pattern, the tungsten reinforcing layer covers the pin area and the bridge arm resistance area of the titanium electrode, and the palladium sensitive layer covers the titanium electrode layer and corresponds to the position of the interdigital electrode pattern.

2. The ultrafast hydrogen response speed hydrogen gas sensor of claim 1, wherein: The thickness of the titanium electrode layer is 8-12 nm, the thickness of the tungsten reinforcing layer is 13-17 nm, and the thickness of the palladium sensitive layer is 11-15 nm.

3. The ultrafast hydrogen response speed hydrogen gas sensor of claim 1, wherein: The titanium electrode layer is provided with a Wheatstone bridge circuit, the Wheatstone bridge circuit comprising a palladium film sensitive resistor R1, a palladium film sensitive resistor R2, a reference resistor R3 and a reference resistor R4; the palladium film sensitive resistor R1 and the reference resistor R4 are arranged at opposite angles and are connected with the bridge input end, and the palladium film sensitive resistor R2 and the reference resistor R3 are arranged at opposite angles and are connected with the bridge input end.

4. The ultrafast hydrogen response speed hydrogen gas sensor of claim 1, wherein: The interdigital electrode pattern has ten pairs of interdigital electrodes, the finger width is 180-220 mu m, the finger spacing is 30-60 mu m, and the sensitive area is 7000 mu m*5500 mu m.

5. A method for preparing a hydrogen sensor with ultrafast hydrogen response speed, characterized in that: The application further discloses a preparation method of the sensor, which comprises the following steps: S1, pretreating the silicon oxide substrate; S2, photoetching an interdigital electrode pattern on the pretreated silicon oxide substrate; S3, depositing a titanium electrode layer on the interdigital electrode pattern; S4, depositing a tungsten reinforcing layer on the pin area and the bridge arm resistance area of the titanium electrode layer; S5, stripping the metal film above the unexposed photoresist on the silicon oxide substrate; S6, depositing a palladium sensitive layer on the corresponding positions of the titanium electrode layer and the tungsten reinforcing layer and the interdigital electrode pattern.

6. The method of claim 5, wherein the hydrogen sensor has an ultrafast hydrogen response speed. S1 specifically comprises sequentially placing the silicon oxide substrate into acetone, ethanol and deionized water for ultrasonic cleaning, and then drying.

7. The method of claim 5, wherein the hydrogen sensor has an ultrafast hydrogen response speed. S3 specifically comprises depositing the titanium electrode layer on the interdigital electrode pattern by electron beam evaporation of a titanium target, and the deposition thickness of the titanium electrode layer is 8-12 nm.

8. The method of claim 5, wherein the hydrogen sensor has an ultrafast hydrogen response speed. S4 specifically comprises depositing the tungsten reinforcing layer on the pin area and the bridge arm resistance area of the titanium electrode layer by electron beam evaporation of a tungsten target, and the deposition thickness of the tungsten reinforcing layer is 13-17 nm.

9. The method of claim 5, wherein the hydrogen sensor has an ultrafast hydrogen response speed. S6 specifically comprises depositing the palladium sensitive layer on the corresponding positions of the titanium electrode layer and the tungsten reinforcing layer and the interdigital electrode pattern by electron beam evaporation of a palladium target, and the deposition thickness of the palladium sensitive layer is 11-15 nm.

10. The method of claim 5, wherein the hydrogen sensor has an ultrafast hydrogen response speed. S5 specifically comprises placing the silicon oxide substrate into a photoresist stripping solution, stripping the metal film above the unexposed photoresist on the silicon oxide substrate, stripping the surface of the silicon oxide substrate, and then rinsing the surface of the silicon oxide substrate.

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