1. A hydrogen sensor core, comprising:

a semiconductor substrate (1);

a source electrode (2) and a drain electrode (3) formed on a semiconductor substrate (1);

a trench region formed on the surface of the semiconductor substrate (1) between the source (2) and the drain (3);

the dielectric layer (4) is formed on the groove region, and the thickness of the dielectric layer (4) positioned on the side face of the groove region is 2 nm-20 nm;

a hydrogen sensitive layer (5) formed on the dielectric layer (4) is used as a grid; the width of the grid electrode is 20 nm-50 nm; the negative junction depth of the grid is 10 nm-20 nm;

and a metal electrode layer (6) formed on the hydrogen sensitive layer (5).

2. The hydrogen sensor core body according to claim 1, wherein the thickness of the hydrogen sensitive layer (5) is 100nm to 120 nm.

3. The hydrogen sensor core according to claim 2, wherein the hydrogen sensitive layer (5) is a metal palladium thin film layer or a palladium-nickel alloy thin film layer.

4. A hydrogen sensor core body according to any of claims 1-3, wherein the semiconductor substrate (1) is a P-type monocrystalline silicon wafer; the doping concentration of boron in the semiconductor substrate (1) is 1 x 10¹⁷cm^-3～8×10¹⁷cm^-3(ii) a The doping concentration of phosphorus in the source electrode (2) is 1 multiplied by 10²⁰cm^-3～8×10²⁰cm^-3(ii) a The doping concentration of phosphorus in the drain electrode (3) is 1 multiplied by 10²⁰cm^-3～5×10²⁰cm^-3。

5. The hydrogen sensor core according to any of claims 1 to 3, characterized in that the dielectric layer (4) is SiO₂、Al₂O₃、SiN_xOne of them.

6. The hydrogen sensor core body according to any one of claims 1 to 3, wherein the metal electrode layer (6) is a silver electrode or a gold electrode; the thickness of the metal electrode layer (6) is 40 nm-50 nm.

7. A method for preparing a hydrogen sensor core according to any one of claims 1 to 6, comprising the steps of:

s1, performing diffusion oxidation on the surface of the semiconductor substrate (1) to form a dielectric layer (4);

s2, identifying and protecting a grid active region of the semiconductor substrate (1), and carrying out phosphorus doping injection and annealing treatment on a source region and a drain region to form a source electrode (2) and a drain electrode (3);

s3, etching the surface of the semiconductor substrate (1) to form a groove area;

s4, performing diffusion oxidation on the surface of the semiconductor substrate (1) in the groove region, and forming a dielectric layer (4) around the groove region;

s5, depositing a metal electrode (6) on the source electrode (2) and the drain electrode (3);

and S6, depositing a hydrogen sensitive layer (5) on the dielectric layer (4) in the groove region.

8. The production method according to claim 7, wherein in step S1, the surface of the semiconductor substrate (1) is subjected to diffusion oxidation using a high-temperature diffusion furnace; the temperature of the diffusion oxidation is 800-900 ℃; the time of the diffusion oxidation is 10 min-30 min;

in step S2, a photolithographic masking method is used to identify and protect the gate active region of the semiconductor substrate (1); carrying out phosphorus doping injection on the source electrode region and the drain electrode region by adopting an ion beam injection machine;

in step S3, etching the surface of the semiconductor substrate (1) by combining an electron beam lithography machine and a reactive ion beam etching machine;

in step S4, a high-temperature diffusion furnace is adopted to carry out diffusion oxidation on the surface of the semiconductor substrate (1) in the groove region; the temperature of the diffusion oxidation is 800-900 ℃; the time of the diffusion oxidation is 10 min-30 min;

in step S5, depositing a metal electrode (6) on the source electrode (2) and the drain electrode (3) by an ion beam coating machine;

in step S6, a hydrogen sensitive layer (5) is deposited on the dielectric layer (4) in the trench region by using an ion beam coater.

9. The production method according to claim 7 or 8, characterized in that, in step S1, before the diffusion oxidation of the surface of the semiconductor substrate (1), the following process is further included: sequentially carrying out ultrasonic cleaning on the semiconductor substrate (1) for 2-10 min by adopting acetone, absolute ethyl alcohol and deionized water, circulating for 3 times totally and drying;

in step S3, the trench depth of the trench region is 30nm to 100 nm.

10. A hydrogen sensor, characterized in that the hydrogen sensor comprises the hydrogen sensor core body as defined in any one of claims 1 to 6 or the hydrogen sensor core body prepared by the preparation method of any one of claims 7 to 9.

Background

The transformer fault is the main reason causing the outage of power plants and substations and the occurrence of local power grid accidents, and the fault of the transformer is reduced, which means that the economic benefit of the power grid is improved, and the national economic safety and social stability are ensured. Therefore, the transformer on-line monitoring is an important component of the on-line monitoring system of the power equipment.

The online monitoring of the dissolved concentration of the fault gas of the oil-immersed transformer is an important component of an online monitoring system of the transformer. The conventional monitoring of transformer oil fault gas adopts laboratory cycle sampling, utilizes gas chromatography instrument to detect the fault gas who dissolves in the oil, has the operation link many, wastes time and energy, shortcomings such as test cycle length, can not in time carry out the early warning to developing faster trouble. Therefore, in the design and installation of transformers of large power plants, which have been recently established, online detection devices are often used in combination to monitor gas dissolved in transformer oil in real time.

When local overheating, local discharge and arc discharge occur in the oil-immersed transformer, the transformer oil and the insulating material therein may be decomposed into gas mainly comprising H₂、CO、CO₂、CH₄And the like.

H can be generated more or less under all fault states of the oil-immersed transformer₂，H₂A significant increase in the content is a reliable indicator that the transformer is already present or will cause various faults. By on-line H₂Measuring device for accurately measuring H dissolved in oil₂The early fault can be detected at the initial stage, scientific basis can be provided for the condition maintenance of the transformer, and the service life of the transformer can be greatly prolonged.

In recent years, the development of the film type hydrogen sensor is rapid, and the detection lower limit, the test precision, the response time and the service life are greatly improved. The current film hydrogen sensor mainly uses a resistance type hydrogen sensor mainly made of metal palladium or palladium alloy materials. However, the thin film resistance sensor with excellent performance can only detect the hydrogen concentration above 500ppm, and although the hydrogen concentration in the environment can be detected more accurately, the sensor cannot give an alarm in time at the initial stage of hydrogen leakage (namely, when the hydrogen concentration in the environment is extremely low), so that accidents are avoided or loss is reduced. In the field of network transformers, especially for high efficiencyA sensitive hydrogen sensor. When an oil-immersed transformer is in a fault state, trace H is usually generated in transformer oil₂Time, transformer fault initial period, H₂The concentration is usually lower than 100ppm, and the thin film resistance type sensor is difficult to detect, so that the fault cannot be found in time.

A field effect transistor (MOSFET) thin film hydrogen sensor has begun to be a focus of attention in the field of research because of its advantages of lower limit of detection hydrogen concentration and higher sensitivity, compared to a resistive hydrogen sensor. H detectable in known MOSFET thin film hydrogen sensors₂The lower limit of concentration reaches dozens of ppm, and the sensitivity reaches 10³A/A is higher than the total ratio. However, the existing MOSFET thin-film hydrogen sensor still has the disadvantages of low sensitivity, long response time and the like, which greatly limits the MOSFET thin-film hydrogen sensor to detect H in the oil-immersed transformer₂Wide application in content. In addition, in the existing hydrogen sensor for online monitoring of hydrogen concentration of an oil-immersed transformer, the hydrogen sensor comprises a hydrogen sensitive probe and a circuit module for signal conversion and outputting an electric signal outwards, a first sensing element of the hydrogen sensor is a catalytic metal thin film resistor, a second sensing element of the hydrogen sensor is a thin film MOS transistor, and the two sensing elements are made of palladium-chromium alloy, palladium-nickel alloy or palladium-gold alloy. The first hydrogen concentration range of the hydrogen sensor is 1000-20000 ppm, the second hydrogen concentration range is 10-1000 ppm, but a double-layer sensitive chip for collecting hydrogen needs to be prepared in a single sensor, and two different demodulation circuit structural forms are matched, so that the preparation process is complex. In addition, the core body of the hydrogen sensor is a core component of the hydrogen sensor, the reasonable device structure design and the preparation process flow of the hydrogen sensor directly determine the lower limit and the response time of the MOSFET thin film hydrogen sensor for detecting the hydrogen concentration, such as the doping concentration, the negative junction depth, the thickness of an oxide layer, the depth of a channel, the width of a grid electrode and the material and the thickness of a sensitive layer of a field effect transistor unit to H₂An important influence factor of the gas concentration response characteristic. Therefore, obtaining a suitable structural design and manufacturing process of the hydrogen sensor core is one of the key points for developing a MOSFET thin film hydrogen sensor with high sensitivity performance.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a hydrogen sensor core with low detection lower limit, high sensitivity and short response time, and also provides a preparation method of the hydrogen sensor core with simple preparation process, convenient operation and low cost and a hydrogen sensor comprising the hydrogen sensor core.

In order to solve the technical problems, the invention adopts the following technical scheme:

a hydrogen sensor core, comprising:

a semiconductor substrate;

a source electrode and a drain electrode formed on the semiconductor substrate;

a trench region formed on the surface of the semiconductor substrate between the source and the drain;

the dielectric layer is formed on the groove area, and the thickness of the dielectric layer positioned on the side surface of the groove area is 2 nm-20 nm;

the hydrogen sensitive layer formed on the dielectric layer is used as a grid; the width of the grid electrode is 20 nm-50 nm; the negative junction depth of the grid is 10 nm-20 nm;

and a metal electrode layer formed on the hydrogen sensitive layer.

As a further improvement of the above technical solution:

as a further improvement of the above technical solution: the thickness of the hydrogen sensitive layer is 100 nm-120 nm.

As a further improvement of the above technical solution: the hydrogen sensitive layer is a metal palladium film layer or a palladium-nickel alloy film layer.

As a further improvement of the above technical solution: the semiconductor substrate is a P-type monocrystalline silicon wafer; the doping concentration of boron in the semiconductor substrate is 1 x 10¹⁷cm^-3～8×10¹⁷cm^-3(ii) a The doping concentration of phosphorus in the source electrode is 1 multiplied by 10²⁰cm^-3～8×10²⁰cm^-3(ii) a The doping concentration of phosphorus in the drain electrode is 1 multiplied by 10²⁰cm^-3～5×10²⁰cm^-3。

As a further improvement of the above technical solution: the dielectric layer is SiO₂、Al₂O₃And SiNx.

As a further improvement of the above technical solution: the metal electrode layer is a silver electrode or a gold electrode; the thickness of the metal electrode layer is 40 nm-50 nm.

As a general technical concept, the present invention also provides a method for preparing the above-mentioned hydrogen sensor core, comprising the steps of:

s1, performing diffusion oxidation on the surface of the semiconductor substrate to form a dielectric layer;

s2, identifying and protecting a grid active region of the semiconductor substrate, and carrying out phosphorus doping injection and annealing treatment on a source region and a drain region to form a source electrode and a drain electrode;

s3, etching the surface of the semiconductor substrate to form a groove area;

s4, performing diffusion oxidation on the surface of the semiconductor substrate of the trench region, and forming a dielectric layer around the trench region;

s5, depositing metal electrodes on the source electrode and the drain electrode;

and S6, depositing a hydrogen sensitive layer on the dielectric layer of the groove region.

As a further improvement of the above technical solution:

in step S1, a high-temperature diffusion furnace is used to perform diffusion oxidation on the surface of the semiconductor substrate; the temperature of the diffusion oxidation is 800-900 ℃; the time of the diffusion oxidation is 10 min-30 min.

As a further improvement of the above technical solution: in step S2, a photolithographic masking method is used to identify and protect the gate active region of the semiconductor substrate; and carrying out phosphorus doping implantation on the source region and the drain region by adopting an ion beam implanter.

As a further improvement of the above technical solution: in step S3, the surface of the semiconductor substrate is etched by using a combination of an electron beam lithography machine and a reactive ion beam etching machine.

As a further improvement of the above technical solution: in step S4, a high-temperature diffusion furnace is used to perform diffusion oxidation on the surface of the semiconductor substrate in the trench region; the temperature of the diffusion oxidation is 800-900 ℃; the time of the diffusion oxidation is 10 min-30 min.

As a further improvement of the above technical solution: in step S5, metal electrodes are deposited on the source and drain electrodes using an ion beam coater.

As a further improvement of the above technical solution: in step S6, a hydrogen sensitive layer is deposited on the dielectric layer in the trench region by an ion beam coater.

As a further improvement of the above technical solution: in step S1, before performing diffusion oxidation on the surface of the semiconductor substrate, the method further includes: and (3) sequentially carrying out ultrasonic cleaning on the semiconductor substrate for 2-10 min by adopting acetone, absolute ethyl alcohol and deionized water, circulating for 3 times totally and drying.

As a further improvement of the above technical solution: in step S3, the trench depth of the trench region is 30nm to 100 nm.

As a general technical concept, the present invention also provides a hydrogen sensor, which includes the hydrogen sensor core body or the hydrogen sensor core body manufactured by the above manufacturing method.

Compared with the prior art, the invention has the advantages that:

(1) the invention provides a hydrogen sensor core, comprising: the semiconductor device comprises a semiconductor substrate, a source electrode and a drain electrode which are formed on the semiconductor substrate, a groove region which is formed on the surface of the semiconductor substrate between the source electrode and the drain electrode, a dielectric layer which is formed on the groove region, and a dielectric layer which is positioned on the side surface of the groove region, wherein the thickness of the dielectric layer is 2 nm-20 nm (when the thickness of the dielectric layer is too thin, the dielectric layer is not easy to prepare, and when the thickness is too thick, the dielectric layer can block electron transmission, so that the performance is reduced); the hydrogen sensitive layer is formed on the dielectric layer, the dielectric layer and the hydrogen sensitive layer are used as a grid electrode, the width of the grid electrode is 20 nm-50 nm, and the negative junction depth of the grid electrode is 10 nm-20 nm; and a metal electrode layer formed on the hydrogen sensitive layer. In the invention, after hydrogen is adsorbed on the surface of the hydrogen sensitive layer, hydrogen molecules are decomposed to form active hydrogen atoms under the catalytic action of the hydrogen molecules, and the hydrogen atoms are diffused through the hydrogen sensitive layerReaching the metal-dielectric layer interface. Under the attraction of interface charges, hydrogen atoms are adsorbed at the interface of the metal-dielectric layer to form a dipole layer, the dipole layer changes the work function of the hydrogen sensitive layer, the barrier height between the hydrogen sensitive layer and the silicon oxide film is changed, the leakage current value of the MOSFET is finally changed, the leakage current value of the MOSFET is correspondingly increased along with the increase of the hydrogen concentration, and the linear relation is basically formed, so that the hydrogen concentration data can be obtained only by detecting the leakage current value. Compared with the traditional resistance type hydrogen sensor core, the hydrogen sensor core has the advantages of low detection lower limit, high sensitivity, short response time and the like, and the thin-film hydrogen sensor prepared by the hydrogen sensor core has the advantages that the detected hydrogen concentration lower limit is very low and reaches 50ppm, the leakage of weak hydrogen can be discovered as soon as possible, and the function of early warning is achieved; the response time is less than 60s, and the change of the hydrogen concentration in the environment can be monitored in real time; sensitivity reaches 10⁵The pressure is higher than A/A, the method can adapt to hydrogen detection under different pressure conditions, and the film hydrogen sensor has very high application value in the field of low-concentration hydrogen leakage detection.

(2) In the hydrogen sensor core body, the doping concentration, the negative junction depth, the thickness of the dielectric layer, the depth of the channel, the width of the grid electrode and the material and the thickness of the sensitive layer are optimized, so that the response time of the hydrogen sensor is greatly shortened to be less than 50s, the sensitivity is improved to be 10⁵A/A is higher than the total ratio.

(3) The invention also provides a preparation method of the hydrogen sensor core, which has the advantages of simple preparation process, convenient operation, low cost and the like, is suitable for large-scale preparation, and is beneficial to industrial application.

(4) The invention also provides a hydrogen sensor which comprises a hydrogen sensor core body, wherein the thin-film hydrogen sensor adopts a groove grid MOSFET (TG-MOSFET) device structure based on palladium, only a sensitive chip for collecting hydrogen in a single layer and a matched demodulation circuit are required to be prepared, the preparation process is simple, the matched demodulation circuit and the algorithm are simple, and the leakage current value and the H current value are used₂The concentration relation curve can be obtained by testing the leakage current value of the MOSFETOut of H₂Concentration, and the sensor device has a highly sensitive measuring effect.

Drawings

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

Fig. 1 is a schematic structural diagram of a hydrogen sensor core body of the present invention.

Fig. 2 is a schematic diagram of the working principle of the hydrogen sensor core body of the invention.

Fig. 3 is a flow chart of a manufacturing process of the hydrogen sensor core body of the invention.

Fig. 4 is a leakage current-hydrogen concentration graph of the hydrogen sensor manufactured in example 1 of the present invention.

Illustration of the drawings:

1. a semiconductor substrate; 2. a source electrode; 3. a drain electrode; 4. a dielectric layer; 5. a hydrogen sensitive layer; 6. and a metal electrode layer.

Detailed Description

The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.

Example 1

As shown in fig. 1, the hydrogen sensor core body of the present embodiment includes:

a semiconductor substrate 1;

a source electrode 2 and a drain electrode 3 formed on the semiconductor substrate 1;

a trench region formed on the surface of the semiconductor substrate 1 between the source electrode 2 and the drain electrode 3;

the dielectric layer 4 is formed on the groove region, and the thickness (h2) of the dielectric layer 4 positioned on the side face of the groove region is 5 nm;

the hydrogen sensitive layer 5 is formed on the dielectric layer 4, the hydrogen sensitive layer 5 is used as a grid, the width (h3) of the grid is 20nm, and the negative junction depth (h1) of the grid is 10 nm;

and a metal electrode layer 6 formed on the hydrogen sensitive layer 5.

As shown in fig. 2, in the present invention, after hydrogen is adsorbed on the surface of the palladium or palladium alloy hydrogen sensitive layer, hydrogen molecules are decomposed to form active hydrogen atoms under the catalytic action of the hydrogen, and the hydrogen atoms diffuse through the metal film to reach the interface of the metal-dielectric layer. Under the attraction of interface charges, hydrogen atoms are adsorbed at the interface of the metal-dielectric layer to form a dipole layer, the dipole layer changes the work function of the hydrogen sensitive layer, the barrier height between the hydrogen sensitive layer and the silicon oxide film is changed, the leakage current value of the MOSFET is finally changed, the leakage current value of the MOSFET is correspondingly increased along with the increase of the hydrogen concentration, and the linear relation is basically formed, so that the hydrogen concentration data can be obtained by detecting the leakage current value.

In this embodiment, the semiconductor substrate 1 is a P-type single crystal wafer, and the doping concentration of boron is 1.5 × 10¹⁷cm^-3。

In this embodiment, the doping concentration of phosphorus in the source 2 is 1.8 × 10²⁰cm^-3The doping concentration of phosphorus in the drain electrode 3 is 1.6X 10²⁰cm^-3。

In this embodiment, the hydrogen sensitive layer 5 is metal palladium, and the thickness (h4) is 100 nm.

In this embodiment, the metal electrode layer 6 is made of metal silver, and the thickness (h5) is 40 nm.

A flow chart of the preparation method of the core body of the hydrogen sensor in the embodiment is shown in fig. 3, and the preparation method includes the following steps:

(1) and (3) taking the P-type monocrystalline silicon piece, respectively ultrasonically cleaning the P-type monocrystalline silicon piece for 5min by using acetone, absolute ethyl alcohol and deionized water with analytical purity in sequence, circularly cleaning for 3 times according to the process, and drying in a drying oven for later use.

(2) Performing diffusion oxidation on the upper surface of the P-type monocrystalline silicon wafer by using a high-temperature diffusion furnace to form SiO with the thickness of 10nm₂Wherein the temperature of the high-temperature diffusion furnace is 850 ℃, and the time of diffusion oxidation is 20 min.

(3) And carrying out grid active region identification and protection on the P-type silicon substrate through a photoetching mask, determining a source region and a drain region in the P-type silicon substrate, carrying out phosphorus doping injection and annealing treatment on the source region and the drain region in an ion injection mode, and forming a source electrode and a drain electrode, wherein the depth of a negative junction is 10 nm.

(4) And depositing a mask on the surface of the P-type silicon substrate by adopting an electron beam lithography machine, forming a grid electrode to-be-etched area with the grid electrode width of 20nm on the surface of the P-type silicon substrate between the source electrode and the drain electrode, and etching the groove by adopting reactive ion etching to form a grid electrode channel with the depth of 50nm, namely forming a groove area on the surface of the P-type silicon substrate between the source electrode 2 and the drain electrode 3.

(5) Carrying out diffusion oxidation on the upper surface of the P-type monocrystalline silicon wafer by adopting a high-temperature diffusion furnace, and carrying out thermal oxidation and annealing treatment to carry out grid SiO₂And preparing a dielectric layer, wherein the temperature of the high-temperature diffusion furnace is 850 ℃, the diffusion oxidation time is 12min, namely forming the dielectric layer 4 around the groove region, and preparing the dielectric layer 4 with the thickness of 5nm on the side surface of the groove region.

(6) And preparing metal electrode layers on the source electrode and the drain electrode by adopting a contact etching and ion beam coating machine, and preparing a hydrogen sensitive layer on the dielectric layer 4 at the bottom of the groove region, wherein the thickness of the metal electrode (silver) is 40nm, and the thickness of the hydrogen sensitive layer (palladium) is 100nm, so as to obtain the hydrogen sensor core.

The hydrogen sensor manufactured in the embodiment includes a core body of the hydrogen sensor manufactured in the embodiment, and is a MOSFET thin film hydrogen sensor.

The leakage current-hydrogen concentration curve of the palladium-based trench gate MOSFET hydrogen sensor prepared in this example 1 was tested using a semiconductor parametric analysis tester. The applied gate voltage was 1.6V, the constant drain power was 0.2V, and the results of the leakage current-hydrogen concentration curve test are shown in fig. 4. Fig. 4 is a leakage current-hydrogen concentration graph of the MOSFET hydrogen sensor made in example 1 of the present invention. The result shows that the MOSFET hydrogen sensor has response at a low-concentration hydrogen mixture of 50ppm, and the higher the hydrogen concentration is, the larger the leakage current is, and the linear relation is basically realized. After a plurality of tests, the MOSFET hydrogen sensor prepared by the invention has high sensitivity (10) to different air pressures applied on the sensor⁵A/a), the sensor device has a highly sensitive measuring effect. In addition, the test results are repeatedThe response speed of the MOSFET hydrogen sensor prepared by the invention is high, and the response time is below 60 s.

Example 2

As shown in fig. 1, the hydrogen sensor core body of the present embodiment includes:

a semiconductor substrate 1;

a source electrode 2 and a drain electrode 3 formed on the semiconductor substrate 1;

a trench region formed on the surface of the semiconductor substrate 1 between the source electrode 2 and the drain electrode 3;

the dielectric layer 4 is formed on the groove region, and the thickness of the dielectric layer 4 positioned on the side face of the groove region is 7 nm;

the hydrogen sensitive layer 5 is formed on the dielectric layer 4, the hydrogen sensitive layer 5 is used as a grid electrode, the width of the grid electrode is 20nm, and the negative junction depth of the grid electrode is 11 nm;

and a metal electrode layer 6 formed on the hydrogen sensitive layer 5.

In this embodiment, the semiconductor substrate 1 is a P-type single crystal wafer, and the doping concentration of boron is 2.2 × 10¹⁷cm^-3。

In this embodiment, the doping concentration of phosphorus in the source 2 is 3.5 × 10²⁰cm^-3The doping concentration of phosphorus in the drain electrode 3 is 2.1X 10²⁰cm^-3。

In this embodiment, the hydrogen sensitive layer 5 is made of palladium-nickel metal and has a thickness of 120 nm.

In this embodiment, the metal electrode layer 6 is made of silver metal and has a thickness of 50 nm.

A method for preparing the core body of the hydrogen sensor in the embodiment includes the following steps:

(1) and (3) taking the P-type monocrystalline silicon piece, respectively ultrasonically cleaning the P-type monocrystalline silicon piece for 5min by using acetone, absolute ethyl alcohol and deionized water with analytical purity in sequence, circularly cleaning for 3 times according to the process, and drying in a drying oven for later use.

(2) Performing diffusion oxidation on the upper surface of the P-type monocrystalline silicon wafer by using a high-temperature diffusion furnace to form SiO with the thickness of 10nm₂Wherein the temperature of the high-temperature diffusion furnace is 850 ℃, and the time of diffusion oxidation is 20 min.

(3) And carrying out grid active region identification and protection on the P-type silicon substrate through a photoetching mask, determining a source region and a drain region in the P-type silicon substrate, carrying out phosphorus doping injection and annealing treatment on the source region and the drain region in an ion injection mode, and forming a source electrode and a drain electrode, wherein the depth of a negative junction is 11 nm.

(4) And depositing a mask on the surface of the P-type silicon substrate by adopting an electron beam lithography machine, forming a grid electrode to-be-etched area with the grid electrode width of 20nm on the surface of the P-type silicon substrate between the source electrode and the drain electrode, and etching the groove by adopting reactive ion etching to form a grid electrode channel with the depth of 50nm, namely forming a groove area on the surface of the P-type silicon substrate between the source electrode 2 and the drain electrode 3.

(5) Carrying out diffusion oxidation on the upper surface of the P-type monocrystalline silicon wafer by adopting a high-temperature diffusion furnace, and carrying out thermal oxidation and annealing treatment to carry out grid SiO₂And preparing a dielectric layer, wherein the temperature of the high-temperature diffusion furnace is 850 ℃, the diffusion oxidation time is 15min, namely forming the dielectric layer 4 around the groove region, and preparing the dielectric layer 4 with the thickness of 7nm on the side surface of the groove region.

(6) And preparing metal electrode layers on the source electrode and the drain electrode by adopting a contact etching and ion beam coating machine, and preparing a hydrogen sensitive layer on the dielectric layer 4 at the bottom of the groove region, wherein the thickness of the metal electrode (silver) is 50nm, and the thickness of the hydrogen sensitive layer (palladium-nickel) is 120nm, so as to obtain the hydrogen sensor core.

The hydrogen sensor manufactured in the embodiment includes a core body of the hydrogen sensor manufactured in the embodiment, and is a MOSFET thin film hydrogen sensor.

In the invention, the influence of different doping concentrations, gate widths and negative junction depths, the thickness of the dielectric layer 4 positioned on the side surface of the groove region and the thickness of the hydrogen sensitive layer on the response performance of the MOSFET thin-film hydrogen sensor is also considered, and the result is shown in Table 1.

TABLE 1 influence of different doping concentrations, gate widths and negative junction depths, thickness of the dielectric layer 4 on the side of the trench region, thickness of the hydrogen sensitive layer on the response performance of the MOSFET thin film hydrogen sensor

Remarking: the corresponding MOSFET hydrogen sensors in example 3, comparative example 1, and comparative example 2 are substantially the same as example 1, except as shown in table 1.

As can be seen from FIG. 1, compared with the conventional hydrogen sensor core, the hydrogen sensor core of the present invention has a lower detection limit of less than 100ppm and a sensitivity of 10⁵A/A, the response time is shortened to be below 50s, and the method has the advantages of low detection lower limit, high sensitivity, short response time, high use value and good application prospect.

The above examples are merely preferred embodiments of the present invention, and the scope of the present invention is not limited to the above examples. All technical schemes belonging to the idea of the invention belong to the protection scope of the invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention, and such modifications and embellishments should also be considered as within the scope of the invention.