Composite amorphous carbon film pressure-sensitive material and method for producing same

Abstract

The objective of the present invention is to provide a composite amorphous carbon film pressure-sensitive material and a method for producing the same. The composite amorphous carbon film pressure-sensitive material comprises an amorphous carbon film layer and a metal fine / nanoparticle layer, which are provided from top to bottom on the surface of an insulating rigid substrate. The metal fine / nanoparticle layer is produced by annealing a metal film layer, and the thickness of the metal film layer is 10 to 100 nm, and the particle density of the metal fine / nanoparticle layer is 150 / mm 2 ~15000 / mm 2 The thickness of the amorphous carbon film layer is 50-400 nm. The present invention also provides a method for fabricating a composite amorphous carbon film pressure-sensitive material. Compared to conventional techniques, the present invention improves sensitivity while maintaining the excellent protective performance of amorphous carbon by adjusting the density of metal microparticles and nanoparticles. The piezoresistance coefficient can reach 36.9. The amorphous structure provides isotropy, showing the same sensitivity in all directions, contributing to a wide range of applications in MEMS systems.

Description

[Technical Field]

[0001] The present invention relates to the technical field of thin film sensors, and more particularly to a composite amorphous carbon film pressure-sensitive material and a method for fabricating the same. [Background technology]

[0002] In recent years, with the rapid development of piezoresistive micro-electromechanical systems (MEMS), piezoresistive pressure sensors have been increasingly widely applied in fields such as automobiles, biomedical applications, and consumer electronics. The performance of piezoresistive pressure sensors is highly dependent on the pressure-sensitive material, among which the piezoresistive gauge factor (GF) is the ratio of the rate of change in electrical resistivity of the material to strain, and reflects the sensitivity of the pressure-sensitive material.

[0003] Currently, the pressure-sensitive materials used in piezoresistive sensors are mainly single-crystal silicon or polycrystalline silicon. However, single-crystal silicon is expensive to manufacture and has anisotropy, while polycrystalline silicon is inexpensive to manufacture and can be miniaturized and integrated, but has the disadvantages of a low piezoresistance coefficient (GF-10) and high temperature sensitivity. In particular, with the rapid development of the high-tech industry, pressure-sensitive materials such as single-crystal silicon and polycrystalline silicon are finding it difficult to meet stable sensing requirements in harsh operating environments such as high temperatures, corrosion, and abrasion, creating an urgent need to develop new pressure-sensitive materials.

[0004] Amorphous carbon film (aC) is a film made of carbon sp 2 and sp 3 It is a broad group of materials formed by the mixture of carbon atoms, which can contain a certain amount of hydrogen (H) and metals and nonmetals. 2 Covalent bonds and sp 3Because it forms an irregular spatial network structure through covalent bonds, it is in an amorphous state, and therefore has isotropic external properties, unlike the anisotropy of crystalline materials.Compared to silicon materials, amorphous carbon has advantages such as excellent mechanical properties and corrosion resistance, and a high piezoresistance coefficient (GF can reach up to 1200).

[0005] However, currently, amorphous carbon with a high GF typically has extremely high resistance and temperature coefficient of resistance (TCR), limiting its application in the field of piezo-resistive sensors. While reducing resistance and TCR has been achieved by introducing metal elements into amorphous carbon using metal target sputtering, the GF generally remains low, at around 1–10, due to the inability to actively control the size, distribution, and conductivity of the metal. Furthermore, high metal doping impairs the protective properties of amorphous carbon, while attempts to keep the metal content low can easily lead to problems such as metal "target poisoning." Therefore, establishing a controllable manufacturing technology for high-performance composite amorphous carbon film pressure-sensitive materials remains a technical challenge. Summary of the Invention [Problem to be solved by the invention]

[0006] The objective of the present invention is to provide a composite amorphous carbon film pressure-sensitive material that can form a new conductive path by introducing metallic micro-nanostructures with adjustable size and distribution into amorphous carbon, which represents a new concept for the development of high-performance amorphous carbon piezoresistance materials. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention employs a technical means to provide a composite amorphous carbon film pressure-sensitive material, which comprises an amorphous carbon film layer and a metal fine / nanoparticle layer provided from top to bottom on the surface of an insulating rigid substrate, the metal fine / nanoparticle layer being produced by annealing a metal film layer, the thickness of the metal film layer being 10 to 100 nm, and the particle density of the metal fine / nanoparticle layer being 150 / mm2 ~15000 / mm 2 The amorphous carbon film layer has a thickness of 50 to 400 nm.

[0008] In this invention, the metal micro- or nano-particle layer is formed by dehumidifying the metal film on the surface of the insulating rigid substrate through annealing, and the size and density of the micro- or nano-particles after dehumidification can be actively controlled by changing the thickness of the metal film before dehumidification and adjusting the corresponding annealing process parameters. Based on the aC piezoresistance characteristic "thick film resistor model" (TFR), aC is a conductive sp 2 The cluster is insulating sp 3 It can be considered as a structure distributed in the matrix, and under the action of stress / strain, sp 2 The change in the hopping behavior of carriers between clusters causes a change in electrical resistance, which manifests as a piezoresistance effect.

[0009] In a preferred embodiment, the piezoresistance coefficient of the composite amorphous carbon film pressure-sensitive material is 12.45 to 36.9.

[0010] In a preferred embodiment, the metal element in the metal film layer is selected from one of Cu, Al, Ni, Ag, Au, and Pt.

[0011] Another object of the present invention is to provide a method for preparing a composite amorphous carbon film pressure-sensitive material, which comprises the steps of: Step S1: placing an insulating rigid substrate in an on-beam composite magnetron sputtering deposition system, and after evacuation, etching the surface of the insulating rigid substrate using argon ions; Step S2: depositing a metal film layer on the surface of the insulating rigid substrate etched in step S1 using a magnetron sputtering method; Step S3 of annealing the metal film layer to obtain a metal fine or nanoparticle layer; and Step S4: depositing an amorphous carbon film on the surface of the metal fine / nanoparticle layer using a magnetron sputtering method to obtain a composite amorphous carbon film pressure-sensitive material.

[0012] Electron transport is achieved by conducting sp 2 The electron transport is controlled by a cluster-to-cluster hopping mechanism. 2 The present invention aims to control the sp in the film by introducing metal fine particles or nanoparticles into the amorphous carbon film. 2 , sp 3 By changing the distribution of clusters and effectively changing the electron transport direction, a new conductive path is formed. By adjusting the thickness of the metal film layer in step S2, it is possible to actively control the size and density of the fine particles and nanoparticles formed after the annealing treatment of the metal film in step S3, and the sp 2 , sp 3 The distribution of the clusters can be influenced to tailor the piezoresistance coefficient of the amorphous carbon film.

[0013] In a preferred embodiment, the specific parameters of the etching in step S1 are: a vacuum level of <2×10 -5 Torr, applied bias voltage of -200 V, anode layer ion source current of 0.2 A, etching time of 20 minutes. In the present invention, by subjecting the substrate to etching treatment before depositing the metal layer, impurities and sparse layers on the substrate surface can be effectively removed, improving the bonding strength between the film and the substrate and reducing the probability of peeling during subsequent metal film plating.

[0014] In a preferred embodiment, the element of the metal film layer in step S2 is Cu, the magnetron sputtering method is DC magnetron sputtering, and the deposition parameters for DC magnetron sputtering are Cu magnetron target current: 1 A, chamber gas pressure: 4.4-4.6 mTorr, applied bias voltage: -100 V, deposition time: 1-4 min, and Cu metal film layer thickness: 13-54 mm. In the present invention, by adjusting the deposition time in step S2 within the above parameter ranges, the film thickness can be changed and the surface morphology of the metal fine / nanoparticle layer after annealing can be adjusted.

[0015] Furthermore, in step S3, the annealing parameters are an annealing temperature of 400 to 800°C and an annealing time of 1 hour. The present invention produces metal fine / nano-particle layers with different morphologies by annealing metal film layers of different thicknesses at appropriate annealing temperatures and times. If the annealing temperature and time are too low, the metal film will not be completely dehumidified. Conversely, if the annealing temperature and time are too high, the metal fine / nano-particles formed will further aggregate and fuse together after the metal film is completely dehumidified, further reducing the surface energy, making it difficult to control the surface morphology formed after final dehumidification.

[0016] In a preferred embodiment, the element of the metal film layer in step S2 is Al, the magnetron sputtering method is DC magnetron sputtering, and the deposition parameters for DC magnetron sputtering are Al magnetron target current: 0.2 A, chamber gas pressure: 1.4-1.5 mTorr, applied bias voltage: -200 V, deposition time: 14-27 minutes, and thickness of the Al metal film layer: 20-100 mm. In the present invention, by adjusting the deposition time in step S2 within the above parameter ranges, the film thickness can be changed and the surface morphology of the metal fine / nanoparticle layer after annealing can be adjusted.

[0017] Furthermore, in step S3, the annealing parameters are an annealing temperature of 600 to 650°C and an annealing time of 3 hours. The present invention produces metal fine / nano-particle layers with different morphologies by annealing metal film layers of different thicknesses at appropriate annealing temperatures and times. If the annealing temperature and time are too low, the metal film will not be completely dehumidified. Conversely, if the annealing temperature and time are too high, the metal fine / nano-particles formed will further aggregate and fuse together after the metal film is completely dehumidified, further reducing the surface energy, making it difficult to control the surface morphology formed after final dehumidification.

[0018] In a preferred embodiment, the magnetron sputtering method in step S4 is high-power impulse magnetron sputtering, and the deposition parameters of the high-power impulse magnetron sputtering are: target material is graphite, pulse power supply voltage is 660 to 670 V, power is 500 W, pulse duty ratio is 10%, gas pressure in the chamber is 8 mTorr, bias voltage is applied is -200 V, and deposition time is 160 minutes. The present invention uses high-power impulse magnetron sputtering to produce amorphous carbon, and since this method has a high ionization rate and can control ion energy over a wide range, the sputtering of the film can be performed. 2 -C / sp 3 This is advantageous for adjusting the -C ratio, and under the above deposition conditions, sp 3 A high content amorphous carbon film is obtained, which has excellent piezoresistance properties. [Effects of the Invention]

[0019] Compared with the prior art, the present invention has the following advantages: Compared to single-crystal silicon, which has a high sensitivity coefficient but is anisotropic, and polycrystalline silicon, which is isotropic but has a low sensitivity coefficient, the composite amorphous carbon film pressure-sensitive material of the present invention can have a high sensitivity coefficient by adjusting the density of the metal micro- and nano-particles, and the piezoresistance coefficient can reach 36.9.The amorphous structure gives it isotropy, and it shows the same sensitivity in all directions, which contributes to a wide range of applications in MEMS systems. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a surface morphology image of an Al metal film layer after annealing in Example 1 of the present invention. [Figure 2] 1 is a particle size distribution graph of surface particles of an Al metal film layer after annealing in Example 1 of the present invention. [Figure 3] 10 is a surface morphology image of the Al metal film layer after annealing in Example 2 of the present invention. [Figure 4] 10 is a particle size distribution graph of surface particles of an Al metal film layer after annealing in Example 2 of the present invention. [Figure 5] 1 is a TEM sample marking site map obtained in Example 2 of the present invention. [Figure 6] 6A and 6B are diagrams showing EELS results at different positions in FIG. 5. [Figure 7] FIG. 6 shows the sp2 and sp3 contents after fitting calculations at different positions in FIG. 5. [Figure 8] 10 is a surface morphology image of a Cu metal film layer after annealing in Example 3 of the present invention. [Figure 9] 10 is a particle size distribution graph of surface particles of a Cu metal film layer after annealing in Example 3 of the present invention. [Figure 10] 10 is a surface morphology image of a Cu metal film layer after annealing in Example 4 of the present invention. [Figure 11] 10 is a particle size distribution graph of surface particles of a Cu metal film layer after annealing in Example 4 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention clearer and more easily understandable, specific embodiments of the present invention will be described in detail below with reference to the drawings.

[0022] It should be understood that the terms used herein are for the purpose of describing specific embodiments and are not intended to limit the invention. It should also be understood that, with respect to numerical ranges within the invention, each intermediate value between the upper and lower limits of that range is specifically disclosed. Each narrower range between any stated value or intermediate value within a stated range and any other stated value or intermediate value within that stated range is also encompassed within the invention. The upper and lower limits of these narrower ranges may independently be included or excluded within the range.

[0023] It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the specification of the invention without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from the specification of the invention. The specification and examples of this application are intended to be illustrative only.

[0024] An embodiment of the present invention provides a composite amorphous carbon film pressure-sensitive material comprising an amorphous carbon film layer and a metal fine / nanoparticle layer, which are provided from top to bottom on the surface of an insulating rigid substrate. The metal fine / nanoparticle layer is prepared by annealing a metal film layer, and the thickness of the metal film layer is 10 to 100 nm, and the particle density of the metal fine / nanoparticle layer is 150 / mm 2 ~15000 / mm 2 The thickness of the amorphous carbon film layer is 50 to 400 nm, and the piezoresistance coefficient of the composite amorphous carbon film pressure-sensitive material is 12.45 to 36.9. In the metal film layer, the metal element is selected from one of Cu, Al, Ni, Ag, Au and Pt.

[0025] In a specific embodiment, the metal element in the metal film layer is Cu or Al. Because Al and Cu have excellent electrical conductivity, introducing these highly conductive metals into amorphous carbon can effectively improve the piezoresistance properties of the film. Because Al and Cu have low melting points and require low annealing temperatures for dehumidification, it is practically easy to prepare the desired metal fine particles or nanoparticles through annealing treatment.

[0026] The present embodiment provides a method for preparing a composite amorphous carbon film pressure-sensitive material, including the following steps: S1: The insulating rigid substrate is placed in an on-beam composite magnetron sputtering deposition system, and after evacuation, the surface of the insulating rigid substrate is etched using argon ions. The specific etching parameters are: vacuum level <2×10 -5 Torr, the applied bias voltage was -200V, the anode layer ion source current was 0.2A, and the etching time was 20 minutes. S2: depositing a metal film layer on the surface of the insulating rigid substrate etched in step S1 using a magnetron sputtering method; S3: Annealing the metal film layer to obtain a metal fine / nanoparticle layer. S4: A composite amorphous carbon pressure-sensitive material is obtained by depositing an amorphous carbon film on the surface of the metal nanoparticle layer using magnetron sputtering. The magnetron sputtering method is high-power impulse magnetron sputtering, and the deposition parameters for high-power impulse magnetron sputtering are graphite target material, pulse power supply voltage of 660-670V, power of 500W, pulse duty ratio of 10%, chamber gas pressure of 8mTorr, applied bias voltage of -200V, and deposition time of 160 minutes.

[0027] In a specific embodiment, the insulating rigid substrate in step S1 is selected from one of Al2O3, AlN, ZrO2, SiO2, and Si3N4. The present invention uses one of the above substrates because these materials are commonly used in current MEMS devices, and in consideration of the current state of industrial production and application, this substrate is used.

[0028] In a specific embodiment, when the element of the metal film layer in step S2 is Cu, the magnetron sputtering method is DC magnetron sputtering, and the deposition parameters for DC magnetron sputtering are: Cu magnetron target current 1 A, chamber gas pressure 4.4-4.6 mTorr, applied bias voltage -100 V, deposition time 1-4 min, and Cu metal film layer thickness 13-54 mm. By adjusting the deposition time in step S2 within the above parameter ranges, the present invention can change the film thickness and adjust the surface morphology of the metal fine / nanoparticle layer after annealing. In step S3, the annealing parameters are: annealing temperature 400-800°C, annealing time 1 hour.

[0029] In a specific embodiment, when the element of the metal film layer in step S2 is Al, the magnetron sputtering method is DC magnetron sputtering, and the deposition parameters of the DC magnetron sputtering are Al magnetron target current: 0.2 A, chamber gas pressure: 1.4-1.5 mTorr, applied bias voltage: -200 V, deposition time: 14-27 minutes, and Al metal film layer thickness: 20-100 mm. In step S3, the parameters of the annealing treatment are annealing temperature: 600-650°C, and annealing time: 3 hours. The technical effects of the present invention will be described below with reference to specific examples.

[0030] Example 1 This example provides a composite amorphous carbon film pressure-sensitive material using silicon dioxide as the substrate material. The composite amorphous carbon film pressure-sensitive material was fabricated on the substrate as follows.

[0031] Step 1: The substrate is ultrasonically cleaned with acetone, dried, and then placed in a vacuum chamber. -5The chamber was evacuated to 2.4 mTorr, and argon gas was introduced into the deposition chamber using an anode layer ion source, maintaining the gas pressure at 2.4 mTorr. A bias of -200 V was applied to the substrate, and the anode layer ion source was turned on, setting the current to 0.2 A, and the ionized argon ions were used to etch the substrate surface, and this process lasted for 20 minutes. Step 2: Turn on the magnetron sputtering source, introduce Ar gas, sputter the aluminum target, maintain the chamber pressure at 1.4 mTorr, set the sputtering target current to 0.2 A, and apply a bias of -200 V to the substrate. This process lasts for 14 minutes, producing an Al metal film layer with a thickness of about 40 nm. Step 3: The Al metal film layer obtained in step 2 is placed in a vacuum annealing furnace and annealed to 2 × 10 -3 The chamber was evacuated to 100 Pa, and the chamber was then annealed at 600°C for 3 hours. The chamber was then cooled to room temperature in the furnace. The Al metal film layer after annealing was observed and measured, and the results are shown in Figures 1 and 2. Figure 1 is a surface morphology image of the Al metal film layer after annealing, and Figure 2 is a particle size distribution graph of the surface particles of the Al metal film layer after annealing in Example 1 of the present invention. Step 4: The sample obtained in step 3 is placed in a vacuum chamber, and high-power impulse magnetron sputtering technology is used to select a high-purity graphite target, and carbon atoms are sputtered from the high-purity graphite target by ionized argon gas to deposit an amorphous carbon film on the substrate surface treated in step 3. The pressure in the vacuum deposition chamber is controlled to 8 mTorr, the high-power pulse power supply voltage is controlled to 670 V, the power is controlled to 500 W, the pulse duty ratio is controlled to 10%, and the bias applied to the substrate is controlled to -200 V. This process lasts for 2 hours and 40 minutes, and an amorphous carbon film layer with a thickness of about 200 nm is produced to obtain a composite amorphous carbon film pressure-sensitive material.

[0032] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0033]

number

[0034] Example 2 The only differences from Example 1 are that in step 2 of this example, the magnetron sputtering duration is 20 minutes, the thickness of the obtained Al metal film layer is 70 nm, and the annealing temperature is 650°C in step 3. The rest are the same as in Example 1, so detailed descriptions thereof will be omitted here.

[0035] The Al metal film layer after annealing was observed and measured, and the results are shown in Figures 3 and 4. Figure 3 is an image of the surface morphology of the Al metal film layer after annealing, and Figure 4 is a particle size distribution graph of the surface particles of the Al metal film layer after annealing.

[0036] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0037]

number

[0038] To investigate the change in the microstructure inside the amorphous carbon film after the addition of the metal film layer, nine different positions were marked on the TEM sample prepared in this example: the flat portion (marked 1 and 2), the spherical bottom portion (marked 3 and 9), the spherical center portion (marked 4 and 8), the spherical top portion (marked 5 and 7), and the spherical apex portion (marked 6), as shown in Figure 5. Electron energy loss spectroscopy (EELS) analysis was performed on the nine different positions. EELS is a method for analyzing the chemical composition and structure of a material by measuring the energy loss due to inelastic electron-electron collisions that occur when electrons pass through a sample. In the case of amorphous carbon materials, the CK absorption edge spectrum in the range of 280 to 305 eV revealed the presence of sp ions in the amorphous carbon film. 2 and sp 3 The content of π can be confirmed by using the "double window method" to analyze the carbon spectrum. * and σ * The feature is partially resolved and fitted to the π centered at 285 eV according to the fitting requirements of the double window method. * The peaks were fitted with a Gaussian function, and σ * The peak was integrated in a small energy window between 290 and 305 eV, and the sp 2 The percentage of bonded carbon atoms can be calculated.

[0039]

number

[0040] Example 3 In this example, the substrate was the same as in Example 1, and a composite amorphous carbon film pressure-sensitive material was prepared on the substrate as follows.

[0041] Step 1: The substrate is ultrasonically cleaned with acetone, dried, and then placed in a vacuum chamber. -5 The chamber was evacuated to 2.4 mTorr, and argon gas was introduced into the deposition chamber using an anode layer ion source, maintaining the gas pressure at 2.4 mTorr. A bias of -100 V was applied to the substrate, and the anode layer ion source was turned on, setting the current to 0.2 A, and the ionized argon ions were used to etch the substrate surface, and this process lasted for 10 minutes. Step 2: Turn on the magnetron sputtering source, introduce Ar gas, sputter the Cu target, maintain the chamber pressure at 3.5 mTorr, set the sputtering target current to 1 A, and apply a bias of -100 V to the substrate. This process lasts for 1 minute, producing a Cu metal film layer with a thickness of about 13 nm. Step 3: The Cu metal film layer obtained in step 2 is placed in a vacuum annealing furnace. -3 The vacuum was drawn to 800 Pa, and the specimen was then held at an annealing temperature of 800°C for 1 hour, after which it was cooled to room temperature in the furnace. The Cu metal film layer after annealing was observed and measured, and the results are shown in Figures 5 and 6. Figure 5 is a surface morphology image of the Cu metal film layer after annealing, and Figure 6 is a particle size distribution graph of the surface particles of the Cu metal film layer after annealing. Step 4: This process lasts for 4 hours and is essentially the same as step 4 in Example 1, except that the thickness is around 300 nm.

[0042] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0043]

number

[0044] Example 4 The only difference from Example 3 is that in step 2 of this example, the magnetron sputtering duration was 2 minutes and the thickness of the obtained Cu metal film layer was 27 nm. Since the other points are the same as those of Example 3, detailed explanations thereof will be omitted here.

[0045] The Cu metal film layer after annealing was observed and measured, and the results are shown in Figures 7 and 8. Figure 7 is an image of the surface morphology of the Cu metal film layer after annealing, and Figure 8 is a particle size distribution graph of the surface particles of the Cu metal film layer after annealing.

[0046] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0047]

number

[0048] By combining the manufacturing processes of Examples 1 to 4, it can be seen that the present invention makes it possible to obtain a composite amorphous carbon film material with a high piezoresistance coefficient by adjusting the size of the introduced metal fine particles or nanoparticles.

[0049] Example 5 In this example, the substrate was the same as in Example 1, and a composite amorphous carbon film pressure-sensitive material was prepared on the substrate as follows.

[0050] Step 1: The substrate is ultrasonically cleaned with acetone, dried, and then placed in a vacuum chamber. -5 The chamber was evacuated to 2.4 mTorr, and argon gas was introduced into the deposition chamber using an anode layer ion source, maintaining the gas pressure at 2.4 mTorr. A bias of -100 V was applied to the substrate, and the anode layer ion source was turned on, setting the current to 0.2 A, and the ionized argon ions were used to etch the substrate surface, and this process lasted for 10 minutes. Step 2: Turn on the magnetron sputtering source, introduce Ar gas, sputter the Ni target, maintain the chamber pressure at 3.5 mTorr, set the sputtering target current to 1 A, and apply a bias of -100 V to the substrate. This process lasts for 1 minute, producing a Ni metal film layer with a thickness of about 13 nm. Step 3: The Ni metal film layer obtained in step 2 is placed in a vacuum annealing furnace and annealed to 2 × 10 -3 The vacuum was drawn to 800 Pa, and the specimen was then held at an annealing temperature of 800°C for 1 hour, after which it was cooled to room temperature in the furnace. Step 4: This process lasts for 4 hours and is essentially the same as step 4 in Example 1, except that the thickness is around 300 nm.

[0051] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0052]

number

[0053] Example 6 In this example, the substrate was the same as in Example 1, and a composite amorphous carbon film pressure-sensitive material was prepared on the substrate as follows.

[0054] Step 1: The substrate is ultrasonically cleaned with acetone, dried, and then placed in a vacuum chamber. -5The chamber was evacuated to 2.4 mTorr, and argon gas was introduced into the deposition chamber using an anode layer ion source, maintaining the gas pressure at 2.4 mTorr. A bias of -100 V was applied to the substrate, and the anode layer ion source was turned on, setting the current to 0.2 A, and the ionized argon ions were used to etch the substrate surface, and this process lasted for 10 minutes. Step 2: Turn on the magnetron sputtering source, introduce Ar gas, sputter the Ag target, maintain the chamber pressure at 3.5 mTorr, set the sputtering target current to 1 A, and apply a bias of -100 V to the substrate. This process lasts for 1 minute, producing an Ag metal film layer with a thickness of about 13 nm. Step 3: The Ag metal film layer obtained in step 2 is placed in a vacuum annealing furnace and annealed. -3 The vacuum was drawn to 800 Pa, and the specimen was then held at an annealing temperature of 800°C for 1 hour, after which it was cooled to room temperature in the furnace. Step 4: This process lasts for 4 hours and is essentially the same as step 4 in Example 1, except that the thickness is around 300 nm.

[0055] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0056]

number

[0057] Example 7 In this example, the substrate was the same as in Example 1, and a composite amorphous carbon film pressure-sensitive material was prepared on the substrate as follows.

[0058] Step 1: The substrate is ultrasonically cleaned with acetone, dried, and then placed in a vacuum chamber. -5 The chamber was evacuated to 2.4 mTorr, and argon gas was introduced into the deposition chamber using an anode layer ion source, maintaining the gas pressure at 2.4 mTorr. A bias of -100 V was applied to the substrate, and the anode layer ion source was turned on, setting the current to 0.2 A, and the ionized argon ions were used to etch the substrate surface, and this process lasted for 10 minutes. Step 2: Turn on the magnetron sputtering source, introduce Ar gas, sputter the Au target, maintain the chamber pressure at 3.5 mTorr, set the sputtering target current to 1 A, and apply a bias of -100 V to the substrate. This process lasts for 1 minute, producing an Au metal film layer with a thickness of about 13 nm. Step 3: The Au metal film layer obtained in step 2 is placed in a vacuum annealing furnace and annealed. -3 The vacuum was drawn to 800 Pa, and the specimen was then held at an annealing temperature of 800°C for 1 hour, after which it was cooled to room temperature in the furnace. Step 4: This process lasts for 4 hours and is essentially the same as step 4 in Example 1, except that the thickness is around 300 nm.

[0059] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0060]

number

[0061] Example 8 In this example, the substrate was the same as in Example 1, and a composite amorphous carbon film pressure-sensitive material was prepared on the substrate as follows.

[0062] Step 1: The substrate is ultrasonically cleaned with acetone, dried, and then placed in a vacuum chamber. -5 The chamber was evacuated to 2.4 mTorr, and argon gas was introduced into the deposition chamber using an anode layer ion source, maintaining the gas pressure at 2.4 mTorr. A bias of -100 V was applied to the substrate, and the anode layer ion source was turned on, setting the current to 0.2 A, and the ionized argon ions were used to etch the substrate surface, and this process lasted for 10 minutes. Step 2: Turn on the magnetron sputtering source, introduce Ar gas, sputter the Pt target, maintain the chamber pressure at 3.5 mTorr, set the sputtering target current to 1 A, and apply a bias of -100 V to the substrate. This process lasts for 1 minute, producing a Pt metal film layer with a thickness of about 13 nm. Step 3: The Pt metal film layer obtained in step 2 is placed in a vacuum annealing furnace and annealed. -3 The vacuum was drawn to 800 Pa, and the specimen was then held at an annealing temperature of 800°C for 1 hour, after which it was cooled to room temperature in the furnace. Step 4: This process lasts for 4 hours and is essentially the same as step 4 in Example 1, except that the thickness is around 300 nm.

[0063] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0064]

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[0065] (Comparative Example 1) In this comparative pressure sensitive material, the substrate material was silicon dioxide, and a layer of pure amorphous carbon film was formed on the substrate as follows.

[0066] Step 1: The substrate is ultrasonically cleaned with acetone, dried, and then placed in a vacuum chamber. -5 The chamber was evacuated to 2.4 mTorr, and argon gas was introduced into the deposition chamber using an anode layer ion source, maintaining the gas pressure at 2.4 mTorr. A bias of -200 V was applied to the substrate, and the anode layer ion source was turned on, setting the current to 0.2 A, and the ionized argon ions were used to etch the substrate surface, and this process lasted for 20 minutes. Step 2: The sample obtained in step 1 is placed in a vacuum chamber, and high-power impulse magnetron sputtering technology is used to select a high-purity graphite target. Carbon atoms are sputtered from the high-purity graphite target using ionized argon gas, and an amorphous carbon film is deposited on the substrate surface treated in step 3. The pressure in the vacuum deposition chamber is controlled to 8 mTorr, the high-power pulse power supply voltage is controlled to 670 V, the power is controlled to 500 W, the pulse duty ratio is controlled to 10%, and the bias applied to the substrate is controlled to -200 V. This process lasts for 2 hours and 40 minutes, producing an amorphous carbon film with a thickness of about 200 nm.

[0067] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0068]

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[0069] (Comparative Example 2) The only difference from Example 2 is that in step 4 of this comparative example, the magnetron sputtering was continued for 6 hours and 40 minutes, and the thickness of the amorphous carbon film layer produced was 500 nm. The rest is the same as in Example 2, so a detailed description thereof will be omitted here.

[0070] The pressure-sensitive material prepared above was subjected to a piezoresistive effect test, in other words, a vertical force was applied to the center of the pressure-sensitive material to deform it, and the change in electrical resistance was observed. Using a three-point piezoresistive coefficient measuring device, a force was applied to the sample to bend it downward by 0.2 mm, and the change in electrical resistance R of the sample before and after bending was observed, and calculated using the following formula.

[0071]

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[0072] In summary, by adjusting the density of the metal micro- and nano-particles and combining it with other key process parameters, the composite amorphous carbon film pressure-sensitive material of the present invention can have a high sensitivity coefficient, with a piezoresistance coefficient reaching 36.9. The amorphous structure provides isotropy, ensuring the same sensitivity in all directions, which will contribute to its wide application in MEMS systems.

[0073] Although the present invention has been disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and such changes and modifications fall within the protection scope of the present invention.

Claims

1. A composite amorphous carbon film pressure-sensitive material is provided with an amorphous carbon film layer and a metal fine / nanoparticle layer, which are provided from top to bottom on the surface of an insulating rigid substrate, and the metal fine / nanoparticle layer is produced by annealing a metal film layer, the thickness of the metal film layer is 10 to 100 nm, and the particle density of the metal fine / nanoparticle layer is 150 / mm ２ ~15000 / mm ２ The thickness of the amorphous carbon film layer is 50 to 400 nm, and in the metal film layer, the metal element is selected from one of Cu, Al, Ni, Ag, Au, and Pt.

2. 2. The composite amorphous carbon film pressure-sensitive material according to claim 1, wherein the composite amorphous carbon film pressure-sensitive material has a piezoresistance coefficient of 12.45 to 36.

9.

3. A method for producing the composite amorphous carbon film pressure-sensitive material according to any one of claims 1 to 2, comprising: Step S1: placing an insulating rigid substrate in an on-beam composite magnetron sputtering deposition system, and after evacuation, etching the surface of the insulating rigid substrate using argon ions; a step S2 of depositing a metal film layer on the surface of the insulating rigid substrate etched in the step S1 by using a magnetron sputtering method; Step S3 of annealing the metal film layer to obtain a metal fine / nano particle layer; a step S4 of depositing an amorphous carbon film on the surface of the metal fine / nanoparticle layer by the magnetron sputtering method to obtain a composite amorphous carbon film pressure-sensitive material; A method for producing a composite amorphous carbon film pressure-sensitive material, comprising:

4. Specific parameters for the etching in step S1 are a degree of vacuum of <2×10 －５ 4. The method for producing a composite amorphous carbon film pressure-sensitive material according to claim 3, characterized in that the applied bias voltage is -200V, the anode layer ion source current is 0.2A, and the etching time is 20 minutes.

5. 4. The method for preparing a composite amorphous carbon pressure-sensitive material according to claim 3, wherein the element of the metal film layer in step S2 is Cu, the magnetron sputtering method is DC magnetron sputtering, and the deposition parameters of the DC magnetron sputtering are: Cu magnetron target current: 1 A, chamber gas pressure: 4.4-4.6 mTorr, applied bias voltage: -100 V, deposition time: 1-4 min, and thickness of the Cu metal film layer: 13-54 mm.

6. 6. The method for producing a composite amorphous carbon film pressure-sensitive material according to claim 5, wherein in step S3, the annealing parameters are an annealing temperature of 400 to 800° C. and an annealing time of 1 hour.

7. 4. The method for preparing a composite amorphous carbon pressure-sensitive material according to claim 3, wherein the element of the metal film layer in step S2 is Al, the magnetron sputtering method is DC magnetron sputtering, and the deposition parameters of the DC magnetron sputtering are: Al magnetron target current: 0.2 A, gas pressure in a chamber: 1.4 to 1.5 mTorr, bias voltage applied: -200 V, deposition time: 14 to 27 minutes, and thickness of the Al metal film layer: 20 to 100 mm.

8. 8. The method for producing a composite amorphous carbon film pressure-sensitive material according to claim 7, wherein in step S3, the annealing parameters are an annealing temperature of 600 to 650° C. and an annealing time of 3 hours.

9. The method for preparing a composite amorphous carbon film pressure-sensitive material according to claim 3, wherein the magnetron sputtering method in step S4 is high-power impulse magnetron sputtering, and the deposition parameters of the high-power impulse magnetron sputtering are as follows: target material is graphite, pulse power supply voltage is 660-670V, power is 500W, pulse duty ratio is 10%, gas pressure in the chamber is 8mTorr, applied bias voltage is -200V, and deposition time is 160 minutes.

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