Thermal protection temperature sensor and preparation method thereof

Abstract

The present invention provides a temperature sensor for thermal protection of two-dimensional nanomaterials and a preparation method thereof, which belongs to the technical field and includes a substrate; a gate electrode arranged on the substrate; a dielectric layer, a part of the dielectric layer is arranged on the substrate, and the other part is arranged on the gate electrode; a source electrode and a drain electrode arranged on the substrate; a bottom thermal protection film arranged on the dielectric layer; an external temperature sensitive layer arranged on the bottom thermal protection film and the source electrode and the drain electrode; a top thermal protection film, a part of the top thermal protection film is arranged on the substrate, and the other part is arranged on the external temperature sensitive layer. The present invention can mass-produce high-temperature sensors at a relatively low cost; the sensor essentially belongs to the category of MEMS sensors, has the basic characteristics of MEMS sensors, and can be applied to sensing in high-temperature environments, greatly exerting the excellent electrical characteristics of two-dimensional film materials, and laying a foundation for the design and manufacture of micro sensors with new structures in high-temperature environments.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a thermal protection temperature sensor based on graphene or other two-dimensional nanomaterials and a preparation method thereof. Background Art

[0002] With the development and popularization of concepts such as "Internet of Things" and "Artificial Intelligence", people's demand for data volume is increasing day by day. Sensors, as ports for data collection, have been applied to all aspects of life. While researchers are constantly pursuing common indicators such as sensor sensitivity, stability, and accuracy, they pay more attention to the expansion of its application range, hoping to use sensors in extreme environments (high temperature, high pressure, strong radiation, etc.). Taking high temperature environment as an example, the current mainstream temperature measurement element, thermocouples, has the disadvantages of large size, low accuracy, and high cost. MEMS sensors have small size, high integration, compatibility with IC design processes, and can be mass-produced, becoming a hot topic of research.

[0003] The development of high-performance sensors depends on the technological innovation and development of sensitive materials. In addition to early semiconductor materials, ceramic materials, and optical fibers, single-crystal silicon has become the mainstream sensitive material for MEMS sensors. However, silicon materials will undergo severe plastic deformation at temperatures above 500°C and cannot meet the needs of testing in extreme environments such as high temperatures. In recent years, with the continuous development of smart materials, new two-dimensional nanofilm materials represented by graphene, molybdenum disulfide, and black phosphorus have excellent electrical, thermal, and mechanical properties due to their unique structural characteristics. For example, the ultra-large specific surface area of ​​two-dimensional nanofilm materials makes the sensor element more sensitive; in addition, the two-dimensional nanofilm materials are stimulated by environmental factors such as light, heat, and force, which will cause changes in the internal carrier mobility, thereby causing changes in electrical properties, which is conducive to the development of new MEMS sensors.

[0004] New device structures are another direction for the development of MEMS sensors. Most existing MEMS sensors use silicon film and mass block structures to measure physical quantities through principles such as piezoresistance, capacitance, resonance or optoelectronic structures. The collected signals are amplified by introducing peripheral circuits, which also amplifies the noise signals, reducing the accuracy of the sensor. Conventional sensor sensitive materials are often in direct contact with the air. Impurity particles such as O2, H2O, and N2 in the air will dope the two-dimensional nanofilm materials, seriously affecting the thermal, mechanical and electrical properties of the materials. In addition, two-dimensional nanofilm materials such as graphene will react chemically with O2 in high temperature environments, resulting in cracking and failure. The above problems have put forward higher requirements for the design of new sensor device structures. Summary of the invention

[0005] The object of the present invention is to provide a thermal protection temperature sensor based on graphene or other two-dimensional nanomaterials and a preparation method thereof, so as to solve at least one technical problem existing in the above-mentioned background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a thermal protection temperature sensor, comprising:

[0008] substrate;

[0009] A gate electrode disposed on the substrate;

[0010] A dielectric layer, wherein a portion of the dielectric layer is disposed on the substrate and another portion of the dielectric layer is disposed on the gate electrode;

[0011] A source electrode and a drain electrode are disposed on the substrate;

[0012] A bottom thermal protection film disposed on the dielectric layer;

[0013] An external temperature sensitive layer is arranged on the bottom heat protection film and the source electrode and the drain electrode;

[0014] A top heat protection film, wherein a portion of the top heat protection film is disposed on the substrate, and another portion of the top heat protection film is disposed on the ambient temperature sensitive layer.

[0015] Preferably, the substrate is made of Al2O3 or SiC.

[0016] Preferably, the external temperature sensitive layer is made of graphene or other two-dimensional nanomaterials.

[0017] Preferably, the dielectric layer is made of one of silicon dioxide, hafnium dioxide or aluminum oxide.

[0018] Preferably, in the gate electrode, the drain electrode and the source electrode, the adhesion layer material is chromium, and the conductive layer material is platinum.

[0019] Preferably, the thickness of the adhesion layer material is 10-30 nm, and the thickness of the conductive layer material is 50-150 nm.

[0020] Preferably, the external temperature sensitive layer is sandwiched between the bottom heat protection film and the top heat protection film (8) to form a sandwich structure, and the area of ​​the bottom heat protection film and the area of ​​the top heat protection film are both larger than the area of ​​the external temperature sensitive layer.

[0021] Preferably, the bottom heat protection film and the top heat protection film are both made of Si3N4.

[0022] In a second aspect, the present invention provides a method for manufacturing the thermal protection temperature sensor as described above, comprising the following steps:

[0023] S1: Cleaning the substrate wafer: Place the Al2O3 or SiC wafer in a mixture of hydrogen peroxide and sulfuric acid in a ratio of 1:4, boil the Al2O3 or SiC wafer at 85°C for 15 minutes to remove surface stains, rinse with deionized water, and dry;

[0024] S2: Making gate electrode: forming a photoresist pattern on Al2O3 or SiC wafer by photolithography technology; depositing metal material by electron beam evaporation or magnetron sputtering technology; removing the photoresist and the metal material attached to the photoresist by stripping process, leaving the electrode pattern, and completing the preparation of the gate electrode;

[0025] S3: Making dielectric layer: Deposit dielectric layer by atomic layer deposition technology or plasma enhanced chemical vapor deposition technology; Use photolithography technology to form a photoresist mask layer in the dielectric layer area; Use inductively coupled plasma etching technology to remove the dielectric layer without photoresist coverage; Use acetone to clean the photoresist, and use a plasma stripper to remove the residual photoresist on the dielectric layer, leaving the dielectric layer pattern, and complete the preparation of the dielectric layer;

[0026] S4: Making source electrode and drain electrode: forming a photoresist pattern on Al2O3 or SiC wafer by photolithography technology; depositing metal material by electron beam evaporation or magnetron sputtering technology; removing the photoresist and the metal material attached to the photoresist by stripping process, leaving the electrode pattern, and completing the preparation of source electrode and drain electrode 5;

[0027] S5: Making a bottom thermal protection film material layer: depositing a bottom thermal protection layer by low pressure chemical vapor deposition technology or plasma enhanced chemical vapor deposition technology; forming a photoresist mask layer in the bottom thermal protection layer area by photolithography technology; removing the bottom thermal protection layer without photoresist coverage by inductively coupled plasma etching technology; cleaning the photoresist with acetone, and removing the residual photoresist on the bottom thermal protection layer by a plasma stripper, leaving the bottom thermal protection layer pattern, and completing the preparation of the bottom thermal protection layer;

[0028] S6: Transferring and patterning the external temperature sensitive layer: transferring the external temperature sensitive layer on the source electrode, the drain electrode and the dielectric layer; using photolithography technology, using photoresist as a barrier layer, and using O2 plasma etching technology to etch the external temperature sensitive layer not covered by the photoresist; using acetone to clean the photoresist on the surface of the external temperature sensitive layer, and completing the transfer and patterning of the external temperature sensitive layer;

[0029] S7: Make a top thermal protection film material layer: deposit the top thermal protection layer by low-pressure chemical vapor deposition technology; use photolithography technology to form a photoresist mask layer in the top thermal protection layer area; use inductively coupled plasma etching technology to remove the top thermal protection layer without photoresist coverage; use acetone to clean the photoresist, and use a Plasma stripper to remove the residual photoresist on the top thermal protection layer, leaving the top thermal protection layer pattern, and complete the preparation of the top thermal protection layer.

[0030] The beneficial effects of the present invention are as follows: high-temperature sensors can be mass-produced at a relatively low cost; the sensor essentially belongs to the category of MEMS sensors, has the basic characteristics of MEMS sensors, and can be applied to sensing in high-temperature environments, greatly utilizing the excellent electrical characteristics of two-dimensional thin film materials, and laying a foundation for the design and manufacture of new-structure microsensors in high-temperature environments.

[0031] Additional aspects and advantages of the present invention will be given in part in the following description, which will become obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0033] Figure 1 This is a schematic diagram of the structure of a high-temperature sensor based on the thermal protection method of graphene or other two-dimensional nano-thin film materials according to an embodiment of the present invention.

[0034] Figure 2 This is a schematic flow chart of a method for manufacturing a high-temperature sensor based on a thermal protection method of graphene or other two-dimensional nanofilm materials according to an embodiment of the present invention.

[0035] Figure 3a Schematic diagram of cleaning Al2O3 or SiC substrate according to an embodiment of the present invention.

[0036] Figure 3b This is a schematic diagram of manufacturing a gate electrode according to an embodiment of the present invention.

[0037] Figure 3c It is a schematic diagram of manufacturing a dielectric layer according to an embodiment of the present invention.

[0038] Figure 3d This is a schematic diagram of manufacturing source electrodes and drain electrodes according to an embodiment of the present invention.

[0039] Figure 3eThis is a schematic diagram of manufacturing a bottom Si3N4 thermal protection layer according to an embodiment of the present invention.

[0040] Figure 3f This is a schematic diagram of transferring and patterning graphene or other two-dimensional nanomaterials according to an embodiment of the present invention.

[0041] Figure 3g This is a schematic diagram of making a top Si3N4 thermal protection layer according to an embodiment of the present invention.

[0042] Figure 4 Schematic diagram of the stability of the device described in an embodiment of the present invention at different temperatures.

[0043] Figure 5 It is a schematic diagram of the stability of the device described in an embodiment of the present invention at different times.

[0044] Among them: 1-substrate; 2-gate electrode; 3-dielectric layer; 4-source electrode; 5-drain electrode; 6-bottom thermal protection film; 7-external temperature sensitive layer; 8-top thermal protection film. DETAILED DESCRIPTION

[0045] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below by the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0046] It should be understood by those skilled in the art that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.

[0047] It should also be understood that terms, such as those defined in commonly used dictionaries, should be understood to have a meaning consistent with that in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless as defined herein.

[0048] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0050] To facilitate understanding of the present invention, the present invention is further explained below with reference to specific embodiments in conjunction with the accompanying drawings, and the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0051] Those skilled in the art should understand that the drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily necessary for implementing the present invention.

[0052] Example 1

[0053] In this embodiment 1, a high temperature sensor based on a thermal protection method of graphene or other two-dimensional nanomaterials is first provided. The high temperature sensor solves the problem that graphene is easily contaminated by impurity particles and oxidized and failed in a high temperature environment by growing a Si3N4 film of a certain thickness on the upper and lower surfaces of the graphene. The high temperature sensor specifically includes:

[0054] Al2O3 or SiC substrate;

[0055] A gate electrode disposed on an Al2O3 or SiC substrate;

[0056] and a dielectric layer, wherein a portion of the dielectric layer is disposed on the Al2O3 or SiC substrate and another portion is disposed on the gate electrode;

[0057] A source electrode and a drain electrode are provided on an Al2O3 or SiC substrate;

[0058] A bottom Si3N4 thermal protection film disposed on the dielectric layer;

[0059] Graphene or other two-dimensional nanomaterials (i.e., external temperature sensitive layer 7) disposed on the dielectric layer, the source electrode, and the drain electrode;

[0060] It also includes a Si3N4 thermal protection film, wherein a portion of the thermal protection film is disposed on an Al2O3 or SiC substrate, and another portion is disposed on top of the graphene or other two-dimensional nanomaterial;

[0061] The substrate material is a high temperature resistant non-metallic material such as Al2O3 or SiC; the dielectric layer is a material such as SiO2, or Al2O3, H f Dielectric layer materials with high dielectric constant and high temperature resistance such as O2;

[0062] The gate electrode, source electrode and drain electrode are made of common electrode materials such as chromium / gold (Cr / Au), chromium / platinum (Cr / Pt), titanium / platinum (Ti / Pt), etc. The melting points of metal materials chromium (Cr), titanium (Ti), gold (Au) and platinum (Pt) are 1857°C, 1668°C, 1064°C and 1772°C respectively. The thickness of adhesion layer materials such as chromium (Cr) and titanium (Ti) is 10-30nm, and the thickness of conductive layer materials such as gold (Au) and platinum (Pt) is 50-150nm.

[0063] Graphene or other two-dimensional nanomaterials are transferred to the bottom Si3N4 film and the source and drain electrodes using a wet transfer method. The Si3N4 film at the bottom of the graphene or other two-dimensional nanomaterials is deposited using plasma enhanced chemical vapor deposition (PECVD) technology with a deposition thickness of 80-100nm, and the Si3N4 thermal protection film at the top of the graphene or other two-dimensional nanomaterials is deposited using low pressure chemical vapor deposition (LPCVD) technology with a deposition thickness of 1um.

[0064] Graphene or other two-dimensional nanomaterials are sandwiched between the bottom Si3N4 thermal protection film and the top Si3N4 thermal protection film to form a sandwich structure. The thermal protection film area is larger than that of graphene or other two-dimensional nanomaterials, thereby achieving full coverage thereof, avoiding contamination by external impurity particles and O2 entering from the edge at high temperature and contacting with temperature-sensitive materials.

[0065] In this embodiment 1, the method for manufacturing the high temperature sensor based on the thermal protection method of graphene or other two-dimensional nanomaterials comprises the following steps:

[0066] S1: Cleaning Al2O3 or SiC wafer: placing Al2O3 or SiC wafer 1 in a mixture of hydrogen peroxide and sulfuric acid in a ratio of 1:4, boiling the Al2O3 or SiC wafer at 85°C for 15 minutes to remove surface stains, rinsing with deionized water, and drying;

[0067] S2: Making a gate electrode: forming a photoresist pattern on an Al2O3 or SiC wafer by photolithography; depositing metal materials by electron beam evaporation or magnetron sputtering; removing the photoresist and the metal material attached to the photoresist by a stripping process, leaving the electrode pattern, and completing the preparation of the gate electrode 2;

[0068] S3: Making a dielectric layer: depositing a dielectric layer with a thickness of 5-50 nm by atomic layer deposition (ALD) or plasma enhanced chemical vapor deposition (PECVD); forming a photoresist mask layer in the dielectric layer region by photolithography; removing the dielectric layer without photoresist coverage by inductively coupled plasma etching (ICP); cleaning the photoresist with acetone, and removing the residual photoresist on the dielectric layer with a plasma stripper, leaving the dielectric layer pattern, and completing the preparation of the dielectric layer;

[0069] S4: Making source and drain electrodes: forming a photoresist pattern on an Al2O3 or SiC wafer by photolithography; depositing metal materials by electron beam evaporation or magnetron sputtering; removing the photoresist and the metal material attached to the photoresist by a stripping process, leaving the electrode pattern, and completing the preparation of the source and drain electrodes;

[0070] S5: Making a bottom Si3N4 thermal protection film material layer: depositing a bottom thermal protection layer with a thickness of 80-100 nm by low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD); forming a photoresist mask layer in the bottom thermal protection layer area by photolithography; removing the bottom thermal protection layer without photoresist coverage by inductively coupled plasma etching (ICP); cleaning the photoresist with acetone, and removing the residual photoresist on the bottom thermal protection layer with a plasma stripper, leaving the bottom thermal protection layer pattern, and completing the preparation of the bottom thermal protection layer;

[0071] S6: Transfer and pattern graphene or other two-dimensional nanomaterial layer: transfer graphene or other two-dimensional nanomaterial layer on the source electrode, drain electrode and dielectric layer; use photolithography technology, use photoresist as a barrier layer, and use O2 plasma etching technology to etch the graphene or other two-dimensional nanomaterial layer without photoresist coverage; use acetone to clean the photoresist on the surface of the graphene or other two-dimensional nanomaterial layer to complete the transfer and patterning of the graphene or other two-dimensional nanomaterial layer;

[0072] S7: Make a top Si3N4 thermal protection film material layer: deposit a top thermal protection layer with a thickness of 1um by low pressure chemical vapor deposition technology (LPCVD); use photolithography technology to form a photoresist mask layer in the top thermal protection layer 8 area; use inductively coupled plasma etching (ICP) technology to remove the top thermal protection layer without photoresist coverage; clean the photoresist with acetone, and use a Plasma stripper to remove the residual photoresist on the top thermal protection layer 8, leaving the top thermal protection layer pattern, and complete the preparation of the top thermal protection layer.

[0073] In summary, in this embodiment 1, a thermal protection method based on graphene or other two-dimensional nanomaterials is provided. The method forms a sandwich structure by growing a certain thickness of silicon nitride (Si3N4) on the upper and lower surfaces of graphene, isolating the direct contact between graphene and air, solving the problem that graphene is easily polluted and ineffective by environmental factors on the one hand, and solving the problem that graphene is oxidized and ineffective in a high temperature environment on the other hand. Based on this protection method, a high-temperature sensor based on graphene or other two-dimensional nanomaterials is designed. The sensor is a planar two-dimensional buried gate field effect tube, including a sapphire (Al2O3) or silicon carbide (SiC) substrate, a dielectric layer, a gate electrode, a source electrode, a drain electrode, a graphene or other two-dimensional nanomaterial layer, and a Si3N4 film layer on the upper and lower surfaces of graphene or other two-dimensional nanomaterials. The method for making a high-temperature sensor based on the thermal protection method of graphene or other two-dimensional nanomaterials can batch prepare graphene or other two-dimensional nanomaterial sensitive elements at a relatively low cost, combining the advantages of good stability and wide applicability of the field effect tube with the excellent electrical properties of the two-dimensional nanomaterial, and greatly improving the sensitivity of the sensor. In addition, graphene or other two-dimensional nanomaterial sensitive elements based on this protection method can achieve effective sensing in extremely harsh environments such as high temperature and high pressure, greatly broadening the application range of sensors.

[0074] Example 2

[0075] The embodiment of the present invention provides a high-temperature sensor based on a thermal protection method of graphene or other two-dimensional nanomaterials, focusing on the design and preparation of a device protection structure. The protection structure uses micro-nano plane processing technology to grow a certain thickness of Si3N4 film on the upper and lower surfaces of graphene to form a sandwich structure to avoid contamination by impurity particles in the environment and direct contact with O2 at high temperatures. By continuously optimizing the physical factors such as the material, shape, thickness and size of the nano protective film, the influence of different growth processes and parameters on the film quality is explored to have better protection performance. In this embodiment 2, the high-temperature sensor is designed as a field effect tube. As a voltage-controlled amplifier device, the size of the output signal can be adjusted by the gate voltage. It has the function of amplification itself, and the field effect tube also has the advantages of high input impedance, strong driving load capacity, low distortion, low noise, and wide safe working area. It has a wide range of applications in the field of sensors.

[0076] In terms of processing technology, high-temperature sensors based on graphene or other two-dimensional nanomaterials thermal protection methods use existing MEMS sensor processing technology. Among them, the key step, the film forming technology of the high-temperature protective layer can be achieved by magnetron sputtering, electron beam evaporation, chemical vapor deposition and other methods. Magnetron sputtering technology has the characteristics of fast deposition speed, good film density, and good film uniformity, but it has disadvantages such as low target material utilization and high damage to the substrate by high-energy particles; electron beam evaporation can evaporate high-melting point materials, and the film purity is high and the quality is good, but the deposition uniformity on the surface of complex structures is poor; chemical vapor deposition (CVD) is divided into plasma enhanced chemical vapor deposition (PECVD) and low pressure chemical vapor deposition (LPCVD). The chemical vapor deposition film forming device is simple and can manufacture refractory metals and various carbides, nitrides, borides, silicides and oxide films at a deposition temperature much lower than their melting point or decomposition temperature. Among them, the working temperature of LPCVD is higher than that of PECVD, and the density and strength of the deposited nanofilm are also improved accordingly. Therefore, selecting the optimal thin film preparation method is crucial to the film quality of the protective layer and the protective effect on the device.

[0077] Specifically, in this embodiment 2, a high-temperature sensor based on a thermal protection method of graphene or other two-dimensional nanofilm materials is provided. The high-temperature sensor solves the problem that graphene is easily contaminated by impurity particles and fails due to oxidation in a high-temperature environment by growing a certain thickness of Si3N4 on the upper and lower surfaces of the graphene. Specifically, the sensor includes: an Al2O3 or SiC substrate 1; a gate electrode 2 arranged on the Al2O3 or SiC substrate 1; a dielectric layer 3 partially arranged on the Al2O3 or SiC substrate 1 and the other part arranged on the gate electrode 2; a source electrode 4 and a drain electrode 5 arranged on the Al2O3 or SiC substrate 1; a bottom thermal protection film 6 arranged on the dielectric layer 3; graphene or other two-dimensional nanomaterials (i.e., an external temperature sensitive layer 7) arranged on the dielectric layer 3 and the source electrode 4 and the drain electrode 5; a top thermal protection film 8 partially arranged on the Al2O3 or SiC substrate 1 and the other part arranged on the graphene or other two-dimensional nanomaterial;

[0078] The substrate material 1 is a high temperature resistant non-metallic material such as Al2O3 or SiC; the dielectric layer 3 is a dielectric layer material such as SiO2, or Al2O3, H fO2 and other dielectric layer materials with high dielectric constant and high temperature resistance; the gate electrode 2, source electrode 4 and drain electrode 5 are made of common electrode materials such as chromium / gold (Cr / Au), chromium / platinum (Cr / Pt), titanium / platinum (Ti / Pt), etc. The melting points of metal materials chromium (Cr), titanium (Ti), gold (Au) and platinum (Pt) are 1857℃, 1668℃, 1064℃ and 1772℃ respectively. The thickness of adhesion layer materials such as chromium (Cr) and titanium (Ti) is 10-30nm, and the thickness of conductive layer materials such as gold (Au) and platinum (Pt) is 50-150nm.

[0079] In this embodiment 2, the manufacturing principle of the sensing part of the sensor is as follows: Graphene or other two-dimensional nanomaterials 7 are transferred to the Al2O3 or SiC substrate 1 and the dielectric layer 3 using a wet transfer method. The thermal expansion coefficient of graphene or other two-dimensional nanomaterials is different from that of the substrate. At high temperatures, stress is generated inside the graphene or other two-dimensional nanomaterials, thereby changing the conductivity of the graphene or other two-dimensional nanomaterials; due to the effects of electron-phonon coupling, intrinsic excitation, etc. in graphene or other two-dimensional nanomaterials, the change in temperature will affect the internal carrier concentration, causing the resistance to change, so that the temperature parameter can be converted into an electrical signal output, thereby realizing effective detection of temperature.

[0080] The manufacturing principle of the protection part of the sensor is as follows: the bottom thermal protection film 6 set at the bottom of the graphene or other two-dimensional nanomaterials adopts the plasma enhanced chemical vapor deposition (PECVD) technology, and the deposition thickness is 80-100nm, and the top thermal protection film 8 set at the graphene or other two-dimensional nanomaterials adopts the low pressure chemical vapor deposition (LPCVD) technology, and the deposition thickness is 1um. The graphene or other two-dimensional nanomaterials are sandwiched between the bottom thermal protection film 6 and the top thermal protection film 8 to form a sandwich structure, and the area of ​​the thermal protection film is larger than that of the graphene or other two-dimensional nanomaterials, so as to achieve full coverage of it, avoid contamination by external impurity particles and O2 from entering from the edge at high temperature and contacting with the temperature-sensitive material. The bottom thermal protection film 6 and the top thermal protection film 8 are both made of Si3N4.

[0081] like Figure 2 As shown, the method for manufacturing a high temperature sensor based on the thermal protection method of graphene or other two-dimensional nanofilm materials in this embodiment 2 includes the following steps:

[0082] S1: Figure 3a As shown, cleaning Al2O3 or SiC wafers:

[0083] S101: placing the Al2O3 or SiC wafer 1 in a mixture of hydrogen peroxide and sulfuric acid in a ratio of 1:4, boiling the sapphire wafer 1 at 85° C. for 15 minutes to remove surface stains, and rinsing and drying with deionized water;

[0084] S2: Figure 3b As shown, make the gate electrode:

[0085] S201: forming a photoresist pattern on the Al2O3 or SiC wafer 1 by photolithography technology;

[0086] S202: Depositing metal material using electron beam evaporation or magnetron sputtering technology;

[0087] S203: removing the photoresist and the metal material attached to the photoresist by a stripping process, leaving the electrode pattern, and completing the preparation of the gate electrode 2;

[0088] S3: Figure 3c As shown, make the dielectric layer:

[0089] S301: depositing a dielectric layer 3 by atomic layer deposition (ALD) or plasma enhanced chemical vapor deposition (PECVD) with a thickness of 5-50 nm;

[0090] S302: forming a photoresist mask layer in the dielectric layer 3 region by using photolithography technology;

[0091] S303: removing the dielectric layer 3 without photoresist coverage by using inductively coupled plasma etching (ICP) technology;

[0092] S304: cleaning the photoresist with acetone, and removing the residual photoresist on the dielectric layer 3 with a plasma stripper, leaving the dielectric layer 3 pattern, and completing the preparation of the dielectric layer 3;

[0093] S4: Figure 3d As shown, make the source electrode and drain electrode:

[0094] S401: forming a photoresist pattern on the Al2O3 or SiC wafer 1 by photolithography technology;

[0095] S402: Depositing metal material using electron beam evaporation or magnetron sputtering technology;

[0096] S403: removing the photoresist and the metal material attached to the photoresist by a stripping process, leaving the electrode pattern, and completing the preparation of the source electrode 4 and the drain electrode 5;

[0097] S5: Figure 3e As shown, the bottom Si3N4 thermal protection film material layer is made:

[0098] S501: depositing a bottom thermal protection film 6 by low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD) technology, with a thickness of 80-100 nm;

[0099] S502: forming a photoresist mask layer in the bottom heat protection film 6 region by using photolithography technology;

[0100] S503: removing the bottom thermal protection layer 6 not covered by the photoresist by using an inductively coupled plasma etching (ICP) technique;

[0101] S504: cleaning the photoresist with acetone, and removing the residual photoresist on the bottom heat protection layer 6 with a plasma stripper, leaving the bottom heat protection film 6 pattern, and completing the preparation of the bottom heat protection film 6;

[0102] S6: Figure 3f As shown, transfer and pattern graphene or other two-dimensional nanomaterial layers:

[0103] S601: transferring a graphene or other two-dimensional nanomaterial layer 7 onto the source electrode 4, the drain electrode 5 and the dielectric layer 3;

[0104] S602: using photolithography technology, taking photoresist as a barrier layer, and etching the graphene or other two-dimensional nanomaterial layer not covered by the photoresist using O2 plasma etching technology;

[0105] S603: Cleaning the photoresist on the surface of the graphene or other two-dimensional nanomaterial layer with acetone to complete the transfer and patterning of the graphene or other two-dimensional nanomaterial layer;

[0106] S7: Figure 3g As shown, make the top Si3N4 thermal protection film material layer:

[0107] S701: depositing a top thermal protection film 8 with a thickness of 1 um by low pressure chemical vapor deposition technology (LPCVD);

[0108] S702: forming a photoresist mask layer in the top heat protection film 8 region by using photolithography technology;

[0109] S703: removing the top thermal protection film 8 without photoresist coverage by using inductively coupled plasma etching (ICP) technology;

[0110] S704: Clean the photoresist with acetone, and use a plasma stripper to remove the residual photoresist on the top heat protection film 8, leaving the top heat protection film 8 pattern, and completing the preparation of the top heat protection film 8.

[0111] To summarize, the thermal protection method based on graphene or other two-dimensional nanomaterials provided in the embodiments of the present invention, taking graphene material as an example, utilizes plasma enhanced chemical vapor deposition (PECVD) and low pressure chemical vapor deposition (LPCVD) to deposit a certain thickness of Si3N4 film on the upper and lower surfaces of graphene to form a sandwich structure. On the one hand, it solves the problem that graphene is easily contaminated by environmental impurities, and on the other hand, it isolates the graphene from direct contact with O2 in a high temperature environment, thereby preventing it from being oxidized and failing.

[0112] Performance test experiment: Put the device into the furnace, start from room temperature (25℃), take out the device and cool it down every 50℃, use semiconductor parameter analyzer to measure the IV characteristic curve of the device, and record the resistance value. The heat treatment time of the device at each temperature node is 90s. In addition, the resistance value change of the device with protective layer within 7 days is recorded and compared with the device without protective layer structure. The experimental results are as follows Figure 4 , Figure 5 shown.

[0113] Analysis of test results: From the optical microscope image of the sample, the silicon nitride morphology remains intact after the device is annealed at 700°C for 90 seconds, and there is no obvious change in structure. From the IV characteristic curve, the resistance of the device does not change significantly under different temperature treatments, and the linearity is good. In addition, the resistance change of the device within 7 days was tested. The device without a protective layer structure has a large fluctuation in device resistance due to the doping contamination of environmental impurities; while the resistance of the device with a protective layer structure does not change significantly.

[0114] The above experiments show that the resistance of graphene with Si3N4 protective layer film added has not changed significantly after being placed for many days, and the IV characteristic curve is good after high-temperature annealing at 700℃, and the morphology and structure remain intact. Most sensors are currently only suitable for environments below 200℃. MEMS sensors based on this protection method can operate stably at 700℃ or even higher temperatures, greatly broadening the application range of sensors. High-temperature sensors and high-temperature and high-pressure sensors prepared based on this protection method have broad application prospects in national defense, military, railway transportation, and industrial production.

[0115] Combining graphene or other two-dimensional nanomaterials with field effect transistors, and utilizing the amplification capability of the field effect transistors themselves, there is no need to introduce additional peripheral amplification circuits, effectively avoiding the noise problem caused by the introduction of external circuits. As a voltage-controlled device, the field effect transistor can change the amplification factor of the field effect transistor by applying voltage to the gate, thereby expanding its detection range. At the same time, graphene or other two-dimensional nanomaterials can respond promptly to changes in physical quantities. The combination of the two can effectively improve the sensitivity of the sensor.

[0116] The proposed protection method is based on micro-nano plane processing technology, which is compatible with traditional IC preparation processes. It can be used to prepare MEMS sensor devices in large quantities and arrays, and has the advantages of small size and low cost. In addition, the protection method for graphene is also applicable to other two-dimensional nanomaterials. Different sensitive materials can be replaced according to different application environments to expand the application range of sensors. Graphene or other two-dimensional nanomaterial components based on this protection method can also be used for pressure, flow and other sensing detection in high-temperature environments, and have a wide range of applications. In addition, the introduction of the protective layer does not cause obvious impurity doping to graphene or other two-dimensional nanomaterials. Graphene still has good electrical and thermal properties, and the prepared high-temperature sensor has high sensitivity and strong stability. The prepared high-temperature sensor has high sensitivity, good linearity of resistance-temperature characteristics at high temperatures, and can respond promptly to small temperature changes. Among them, the temperature-sensitive mechanism of graphene can be comprehensively explained by mechanisms such as electron-phonon coupling, thermal expansion effect, intrinsic excitation, and electron-charged particle interaction, which has a strong theoretical basis.

[0117] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative work on the basis of the technical solution disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A thermal protection temperature sensor, characterized in that: include: Substrate (1); A gate electrode (2) disposed on a substrate (1); A dielectric layer (3), wherein a portion of the dielectric layer (3) is disposed on the substrate (1) and another portion of the dielectric layer (3) is disposed on the gate electrode (2); A source electrode (4) and a drain electrode (5) arranged on a substrate (1); A bottom thermal protection film (6) disposed on the dielectric layer (3); An external temperature sensitive layer (7) is arranged on the bottom heat protection film (6) and the source electrode (4) and the drain electrode (5); A top heat protection film (8), wherein a portion of the top heat protection film (8) is disposed on the substrate (1), and another portion of the top heat protection film (8) is disposed on the external temperature sensitive layer (7).

2. The thermal protection temperature sensor according to claim 1, characterized in that: The substrate is made of Al2O3 or SiC.

3. The thermal protection temperature sensor according to claim 1, characterized in that: The material of the external temperature sensitive layer is graphene or other two-dimensional nanomaterials.

4. The thermal protection temperature sensor according to claim 1, characterized in that: The dielectric layer (3) is made of a material selected from the group consisting of silicon dioxide, hafnium dioxide and aluminum oxide.

5. The thermal protection temperature sensor according to claim 1, characterized in that: In the gate electrode (2), the drain electrode (5) and the source electrode (4), the adhesion layer material is chromium and the conductive layer material is platinum.

6. The thermal protection temperature sensor according to claim 5, characterized in that: The thickness of the adhesion layer material is 10-30 nm, and the thickness of the conductive layer material is 50-150 nm.

7. The thermal protection temperature sensor according to claim 1, characterized in that: The external temperature sensitive layer (7) is sandwiched between the bottom heat protection film (6) and the top heat protection film (8) to form a sandwich structure, and the area of ​​the bottom heat protection film (6) and the area of ​​the top heat protection film (8) are both larger than the area of ​​the external temperature sensitive layer (7).

8. The thermal protection temperature sensor according to claim 1 or 7, characterized in that: The bottom heat protection film (6) and the top heat protection film (8) are both made of Si3N4.

9. A method for manufacturing a thermal protection temperature sensor according to any one of claims 1 to 8, characterized in that: The steps include: S1: Cleaning the substrate wafer: Place the Al2O3 or SiC wafer in a mixture of hydrogen peroxide and sulfuric acid in a ratio of 1:4, boil the Al2O3 or SiC wafer at 85°C for 15 minutes to remove surface stains, rinse with deionized water, and dry; S2: Making gate electrode: forming a photoresist pattern on Al2O3 or SiC wafer by photolithography technology; depositing metal material by electron beam evaporation or magnetron sputtering technology; removing the photoresist and the metal material attached to the photoresist by stripping process, leaving the electrode pattern, and completing the preparation of the gate electrode; S3: Making dielectric layer: Deposit dielectric layer by atomic layer deposition technology or plasma enhanced chemical vapor deposition technology; Use photolithography technology to form a photoresist mask layer in the dielectric layer area; Use inductively coupled plasma etching technology to remove the dielectric layer without photoresist coverage; Use acetone to clean the photoresist, and use a plasma stripper to remove the residual photoresist on the dielectric layer, leaving the dielectric layer pattern, and complete the preparation of the dielectric layer; S4: Making a source electrode and a drain electrode: forming a photoresist pattern on an Al2O3 or SiC wafer by photolithography; depositing a metal material by electron beam evaporation or magnetron sputtering; removing the photoresist and the metal material attached to the photoresist by a stripping process, leaving the electrode pattern, and completing the preparation of the source electrode (4) and the drain electrode (5); S5: making a bottom thermal protection thin film material layer: depositing a bottom thermal protection layer by low pressure chemical vapor deposition technology or plasma enhanced chemical vapor deposition technology; forming a photoresist mask layer in the bottom thermal protection layer area by using photolithography technology; The bottom thermal protection layer without photoresist coverage is removed by using inductively coupled plasma etching technology; Clean the photoresist with acetone, and use a plasma stripper to remove the residual photoresist on the bottom thermal protection layer, leaving the bottom thermal protection layer pattern, and completing the preparation of the bottom thermal protection layer; S6: transferring and patterning an external temperature sensitive layer: transferring an external temperature sensitive layer on the source electrode, the drain electrode and the dielectric layer; Using photolithography technology, taking photoresist as a barrier layer, and using O2 plasma etching technology to etch the external temperature sensitive layer not covered by the photoresist; using acetone to clean the photoresist on the surface of the external temperature sensitive layer, completing the transfer and patterning of the external temperature sensitive layer; S7: making a top thermal protection thin film material layer: depositing a top thermal protection layer by low pressure chemical vapor deposition technology; forming a photoresist mask layer in the top thermal protection layer region by using photolithography technology; The top thermal protection layer without photoresist coverage is removed by inductively coupled plasma etching technology; The photoresist is cleaned with acetone, and the residual photoresist on the top thermal protection layer is removed with a plasma stripper, leaving the top thermal protection layer pattern, thereby completing the preparation of the top thermal protection layer.

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