High-hardness ta-hf-w nitride film and method for manufacturing the same

Abstract

The application discloses a high-hardness Ta-Hf-W nitride film and a preparation method and application thereof. The nitride film is composed of Ta, Hf, W and N atoms, and is expressed by a chemical formula: Ta a Hf b W c N d ; wherein a, b, c and d represent atomic ratios, the value range of a is 17-21, the value range of b is 7-17, the value range of c is 29-31, the value range of d is 31-47, and a+b+c+d=100; the Ta-Hf-W nitride film is prepared by using a reaction formula multi-target direct-current magnetic control sputtering technology, has a single-phase face-centered cubic crystal structure, the surface roughness of the film is 1.85-2.20 nm, the hardness is 28.4-36.1 GPa, and the elastic modulus is 308.3-357.2 GPa; and the film is applied to the surface modification of structure materials in an extreme service condition field, so that the strength, hardness and wear resistance of the material surface are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of alloy materials, and particularly relates to a high-hardness Ta-Hf-W nitride film and a preparation method thereof. BACKGROUND

[0002] In recent years, high-entropy ceramics, especially high-entropy nitride (HENs) ceramic materials have attracted extensive attention due to their excellent properties. It has been reported that the introduction of nitrogen into high-entropy alloy solid solutions has a significant impact on the structure and microstructure and performance, and can improve the mechanical properties to a certain extent.

[0003] Although the research on high-entropy alloys mainly focuses on bulk materials, the strengthening theory has been extended to ceramic thin film materials based on the concept of high-entropy alloys. The preparation of high-entropy boride, carbide, nitride and oxide thin films can be achieved by adding non-metallic elements such as B, C, N or O. In particular, high-entropy nitride thin films have higher hardness, wear resistance and oxidation resistance than high-entropy alloys, and therefore have extremely high potential application value as hard protective thin films.

[0004] Traditional nitride coatings, such as TiN and CrN, are used as wear-resistant coatings in many industrial fields such as cutting and forming tools, mechanical parts, etc. due to their high hardness. In order to improve the performance of specific tools and dies in applications, it is necessary to continuously develop new hard coatings. Ternary and quaternary nitride coatings such as TiAlN, TiCN and TiSiCN have been developed by incorporating metal and metalloid elements.

[0005] Magnetron sputtering has the characteristics of high deposition rate, good film quality, controllable performance, good substrate adhesion and less impurities, and has become the most common thin film preparation method. Single target sputtering is the most commonly used form of magnetron sputtering deposition, i.e. the sputtering target material is a single alloy target material. This technology can achieve accurate control of the stoichiometric ratio of the thin film composition; but the disadvantage is that the preparation of alloy targets is complex and costly. With the continuous improvement of preparation technology, multi-target magnetron sputtering process has also been increasingly applied to the preparation and research of multi-main element thin films. Multi-target magnetron sputtering uses multiple pure metal targets or binary alloy targets, which can effectively avoid the complex preparation process of single alloy targets. Moreover, by changing the sputtering power of the target, the sputtering time of the target and the angle of the target perpendicular to the center line of the sample table, a variety of component thin films can be prepared, making the thin film preparation more flexible and conducive to high-throughput screening of thin film composition and performance.

[0006] However, there has been no extensive research on refractory metals such as Ta, Hf and W, so this patent mainly uses refractory metals such as Ta, Hf and W as main elements to deposit nitride thin films through reactive multi-target magnetron sputtering process. SUMMARY

[0007] In order to solve the problem that the nitride coating of ternary and quaternary system in the prior art has not been researched for refractory metals such as Ta, Hf and W, the application provides a high-hardness Ta-Hf-W nitride film and a preparation method thereof.

[0008] The application provides a Ta a Hf b W c N d The film is prepared by using a reactive multi-target direct-current magnetron sputtering technology, the surface roughness of the obtained film is 1.85-2.20 nm, the hardness of the film is 28.4-36.1 GPa, the elastic modulus is 308.3-357.2 GPa, and the film has a more extensive application prospect and can be applied to surface modification of structural materials in extreme service conditions such as aerospace, national defense, chemical industry and the like, so as to improve the strength, hardness and wear resistance of the material surface.

[0009] The application provides a high-hardness Ta-Hf-W nitride film and a preparation method thereof.

[0010] (1) ultrasonic cleaning of a substrate in anhydrous ethanol, rinsing with deionized water, drying of the surface by blowing with dry compressed nitrogen, and fixing on a sample table;

[0011] (2) placing required high-purity metal targets Ta, Hf and W on three direct-current sputtering target positions of a deposition chamber, and respectively adjusting the angle of the metal targets perpendicular to the center line of the sample table and the vertical distance between the metal targets and the substrate;

[0012] (3) first, vacuumizing the deposition chamber to a required experimental condition, then introducing high-purity argon and nitrogen, respectively setting required gas flow, adjusting the working gas pressure of the deposition chamber, setting the sputtering power of each metal target, shielding the substrate with a baffle and pre-sputtering the target;

[0013] (4) then, setting the rotation speed of the substrate and opening the baffle to perform formal sputtering and film deposition, and obtaining a Ta-Hf-W nitride film according to required process parameters.

[0014] The application adopts the method of reactive multi-target direct-current magnetron sputtering film deposition, and obtains the Ta-Hf-W nitride film which is uniform in composition, small in surface roughness, high in hardness and elastic modulus.

[0015] The application aims to realize the technical scheme as follows

[0016] A high-hardness Ta-Hf-W nitride film, in particular, Ta a Hf b W c N d The nitride film is composed of Ta, Hf, W and N atoms, and the chemical formula is: Ta a Hf b W c N d ; wherein a, b, c and d all represent atomic ratios, the value range of a is 17-21, the value range of b is 7-17, the value range of c is 29-31, the value range of d is 31-47, and a+b+c+d=100; Ta, Hf and W target materials are prepared into Ta a Hf b W c N d nitride film through reactive magnetron sputtering film deposition in a set sputtering power and different nitrogen gas flow; the nitride film has four components and a single-phase face-centered cubic (FCC) crystal structure, the surface roughness is 1.85-2.20 nm, the film hardness is 28.4-36.1 GPa, and the elastic modulus is 308.3-357.2 GPa.

[0017] The preparation method of the high-hardness Ta-Hf-W nitride film comprises the following steps:

[0018] 1) the substrate is cleaned in anhydrous ethanol for 10 min to remove the pollutants attached to the surface of the substrate, and then the substrate is washed with deionized water;

[0019] 2) the cleaned substrate is blown dry with compressed nitrogen to keep the substrate surface clean and prevent water stains from remaining;

[0020] 3) the smooth surface of the substrate is fixed on the furnace plate with the furnace plate fixed on the sample table of the deposition chamber of the magnetron sputtering film deposition equipment, and the sample table baffle is adjusted to completely cover the substrate;

[0021] 4) Ta, Hf and W metal block target materials are respectively placed in three different direct current target positions of the deposition chamber, and the angle of each target material perpendicular to the center line of the sample table and the vertical distance between each target material and the sample table are adjusted;

[0022] The Ta, Hf and W target materials are all high-purity metal blocks with a purity of ≥99.95%, a diameter of 60 mm and a thickness of 3-5 mm;

[0023] The angle of the target relative to the center line of the sample table is 20-40°; the vertical distance between the Ta, Hf, W metal target and the sample table is 5-15 cm;

[0024] 5) Firstly, the deposition chamber is vacuumed to less than 8.0 Pa by a mechanical pump, and then the vacuum degree of the deposition chamber is vacuumed to less than 6.0*10 -4 Pa by a molecular pump; -4

[0025] 6) Then, argon and nitrogen are introduced into the deposition chamber, the gas flow is adjusted respectively, the working pressure is adjusted to 0.7-0.9 Pa, the direct current power supply of the corresponding target is turned on, the sputtering power of the target is set respectively, the target is pre-sputtered for 10-15 min to remove the impurities such as oxides formed on the surface of the target, wherein the sputtering power of the Ta target is 100 W, the sputtering power of the Hf target is 100 W, and the sputtering power of the W target is 100 W;

[0026] 7) The rotation rate of the sample table is set to 15-30 r / min, the substrate shutter is opened, and the sputtering deposition is carried out on the smooth surface of the substrate, the sputtering time is 1 h, and the thin film is obtained;

[0027] 8) After the sputtering deposition is completed, the direct current power supply is turned off, the argon and nitrogen are turned off, the rotation of the sample table is stopped, the thin film is cooled to room temperature in a vacuum state, and then taken out to reduce the oxidation pollution, and finally the Ta a Hf b W c N d nitride thin film is obtained on the substrate. a Hf b W c N d ; wherein a, b, c and d all represent atomic ratio, the value range of a is 17-21, the value range of b is 7-17, the value range of c is 29-31, the value range of d is 31-47, and a+b+c+d=100; the component number of the nitride thin film is four, has a single-phase face-centered cubic (FCC) crystal structure, the surface roughness is 1.85-2.20 nm, the hardness of the thin film is 28.4-36.1 GPa, and the elastic modulus is 308.3-357.2 GPa.

[0028] Further, the smooth surface of the substrate is polished by a damping cloth before the ultrasonic cleaning in step 1).

[0029] ​Further, the substrate in step 1) is a single crystal silicon wafer, which is commercially available P-type and has a crystal direction of <100>.

[0030] Further, the ultrasonic frequency in the ultrasonic cleaning in step 1) is 60-80 Hz.

[0031] Further, the angle of the target material relative to the center line perpendicular to the sample table in step 4) is 20-40°, and under the condition that other preparation parameters are the same, the angle will affect the deposition rate of the thin film, and too small or too large will affect the thickness of the thin film, when the angle is 20-40°, the projection area of the target material relative to the substrate is relatively large, the deposition rate is relatively fast, and the efficiency is high.

[0032] Further, the total gas flow of argon and nitrogen in step 6) is 40 sccm, and the nitrogen gas flow is 4-16 sccm, wherein the nitrogen accounts for 10%-40% of the total gas flow; correspondingly, the argon gas flow is 24-36 sccm, and the purity of the two gases is ≥99.999%.

[0033] Further, the sputtering power in step 6) is required, when the sputtering power is lower, the target material is not easy to ignite, and when the sputtering power is higher, the equipment is easy to overheat, which affects the sputtering effect.

[0034] The beneficial effects of the present application are:

[0035] Compared with the prior art, the present application has the following advantages:

[0036] 1. The preparation method of the high-hardness Ta-Hf-W nitride thin film can prepare the Ta a Hf b W c N d The reaction formula multi-target direct current magnetron sputtering technology is adopted, that is, the multi-target co-sputtering and gas reaction sputtering are simultaneously performed, the target material is a pure metal block target material, and the gas is high-purity argon and nitrogen. The method can avoid a complex target material preparation process, and various chemical component nitride thin films can be prepared by changing the nitrogen gas flow or the sputtering time of the target material. The method has the characteristics of high deposition rate, wide material applicability, good repeatability, etc. In the preparation process of the present application, pure metal target material is adopted, the raw material is simple and easy to obtain, and the present application is suitable for large-scale industrial production.

[0037] 2. The high-hardness Ta-Hf-W nitride thin film can prepare the Ta a Hf b W c N dThe nitride film has uniform element distribution, single-phase face-centered cubic crystal structure, high hardness and elastic modulus, and small surface roughness. a Hf b W c N d The nitride film has high hardness and elastic modulus, and small surface roughness.

[0038] 3. The high-hardness Ta-Hf-W nitride film has four elements of Ta, Hf, W and N, and can form a high-hardness nitride film with a large range of composition. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the drawings shown.

[0040] Figure 1 The Ta 21 Hf 17 W 31 N 31 nitride film in the embodiment 1 of the present application is shown in the surface and cross-section morphology SEM images.

[0041] Figure 2 The Ta 21 Hf 17 W 31 N 31 nitride film in the embodiment 1 of the present application is shown in the element surface scanning EDS images.

[0042] Figure 3 The Ta 21 Hf 17 W 31 N 31 nitride film in the embodiment 1 of the present application is shown in the surface morphology AFM images.

[0043] Figure 4 The Ta 21 Hf 17 W 31 N 31 nitride film in the embodiment 1 of the present application is shown in the XRD images.

[0044] Figure 5 The Ta 20 Hf8W 30 N 42 nitride film in the embodiment 2 of the present application is shown in the surface and cross-section morphology SEM images.

[0045] Figure 6 Ta for Example 2 of the present invention 20 Hf8W 30 N 42 Elemental mapping EDS of nitride film;

[0046] Figure 7 Ta for Example 2 of the present invention 20 Hf8W 30 N 42 Surface topography AFM of nitride film;

[0047] Figure 8 Ta for Example 2 of the present invention 20 Hf8W 30 N 42 XRD of nitride film;

[0048] Figure 9 Ta for Example 3 of the present invention 17 Hf7W 29 N 47 Surface and cross-section topography SEM of nitride film;

[0049] Figure 10 Ta for Example 3 of the present invention 17 Hf7W 29 N 47 Elemental mapping EDS of nitride film;

[0050] Figure 11 Ta for Example 3 of the present invention 17 Hf7W 29 N 47 Surface topography AFM of nitride film;

[0051] Figure 12 Ta for Example 3 of the present invention 17 Hf7W 29 N 47 XRD of nitride film.

[0052] Figure 13 Macro topography of Ta-Hf-W nitride film prepared in Comparative Example 1 of the present invention with 50% nitrogen flow rate. DETAILED DESCRIPTION

[0053] The following examples are presented to provide a more detailed, complete description of the application, to set forth its advantages and features, and to define the scope of the application more precisely from the viewpoint of the skilled person, but are not intended to limit the scope of the application.

[0054] The raw materials used in the following examples are commercially available.

[0055] 1. The high-purity argon and nitrogen used in the application have a purity of ≥ 99.999%.

[0056] 2. The Ta, Hf and W target materials used in the preparation of the thin film have a purity of ≥ 99.95%, and the single crystal silicon wafer is a commercially available product.

[0057] 3. The high vacuum magnetron sputtering coating equipment used in the preparation of the thin film is a magnetron sputtering coating equipment produced by Shenyang Scientific Instrument Co., Ltd. of the Chinese Academy of Sciences; the mechanical pump and the molecular pump are matching equipment for the high vacuum magnetron sputtering coating equipment produced by the same company.

[0058] Example 1

[0059] A method for preparing a high-hardness Ta-Hf-W nitride thin film, specifically a Ta 21 Hf 17 W 31 N 31 nitride thin film, comprising the following steps:

[0060] A commercially available P-type single crystal silicon wafer with a <100> crystal orientation is treated with damping polishing, then cleaned in anhydrous ethanol for 10 minutes under ultrasonic waves at a frequency of 60-80 Hz to remove impurities and contaminants attached to the surface of the substrate, then the substrate is rinsed clean with deionized water, and then dried with compressed nitrogen to prevent the residual of surface water stains; the smooth surface of the substrate is fixed on a furnace tray, the furnace tray is fixed on a sample stage in the deposition chamber of a magnetron sputtering thin film deposition system equipment, and the sample stage baffle is adjusted to completely cover the substrate; the metal target materials Ta, Hf and W are placed in three different direct current target positions in the deposition chamber in turn, the angle of each metal target material perpendicular to the center line of the sample stage is adjusted to 30°, and the vertical distance between the metal target material and the sample stage is adjusted to 10 cm; the deposition chamber is first evacuated to less than 8.0 Pa by a mechanical pump, and then the vacuum degree of the deposition chamber is further evacuated to less than 6.0×10 -4Pa; High-purity argon gas (≥99.999%) with a purity of ≥99.999% was introduced into the deposition chamber at a flow rate of 36 sccm, and high-purity nitrogen gas (≥99.999%) with a purity of ≥99.999% was introduced at a flow rate of 4 sccm. The working pressure was set to 0.7 Pa, and the sputtering power of the Ta target, Hf target, and W target was set to 100 W. The targets were pre-sputtered for 10 min to remove oxides and other impurities adhering to the target surface. After pre-sputtering, the sample stage rotation speed was set to 15 r / min, the sample stage baffle was opened, and formal sputtering began for 1 h. After sputtering, the DC constant current power supply and argon gas switch were turned off, the sample stage rotation was stopped, and the film was allowed to cool to room temperature under vacuum before being removed to reduce oxidation contamination. Finally, the Ta film was obtained on the silicon wafer. 21 Hf 17 W 31 N 31 Nitride thin films.

[0061] The chemical composition of the nitride film was analyzed using an Oxford X-act energy-dispersive X-ray spectroscopy (EDS, mounted on a scanning electron microscope). The surface and cross-sectional morphology SEM images and elemental surface scanning EDS spectra of the nitride film are attached. Figure 1 and 2 As shown: According to the quantitative calculation results of the software, the composition of this nitride film is Ta. 21 Hf 17 W 31 N 31 .

[0062] Ta was imaged using a Dimension ICON atomic force microscope (AFM) from Bruker GmbH, Germany. 21 Hf 17 W 31 N 31 The surface morphology of the nitride film was analyzed using tapping mode, with a scan area of ​​10 μm × 10 μm. The surface roughness (Ra) of the film was analyzed using NanoScope Analysis software. The results are attached. Figure 3 Shown: Ta 21 Hf 17 W 31 N 31 The surface AFM morphology of the nitride film is needle-like, and the surface roughness is 2.20 nm.

[0063] The surface roughness of a thin film affects its wear resistance. The coefficient of friction and wear rate of a thin film generally increase with increasing surface roughness. This is because a rough surface has a smaller contact area and higher contact pressure, which leads to a higher coefficient of friction and wear loss. Therefore, a smaller surface roughness is beneficial to improving the wear resistance of the thin film.

[0064] Ta was analyzed using a D8 Advance X-ray diffractometer (XRD) from BRUKER AXS GmbH, Germany. 21 Hf 17 W 31 N 31 XRD phase analysis was performed on the nitride thin film. The operating voltage was 40 kV, the operating current was 40 mA, the X-ray source was Cu-Ka (λ = 0.15418 nm), the grazing incidence angle was 1°, the scanning speed was 4° / min, the scanning step size was 0.02° / step, and the scanning range was 10°–90°. The results are attached. Figure 4 As shown. Based on the extinction rules of lattice diffraction, the five diffraction peaks marked with black rhombuses in the spectrum can be determined to correspond to the (111), (200), (220), (311), and (222) crystal planes of the FCC structure phase, indicating that Ta 21 Hf 17 W 31 N 31 The crystal structure of the nitride film is a single-phase face-centered cubic (FCC) structure.

[0065] Because thin films are micro- and nano-scale materials, their hardness can only be measured using a nanoindenter. Vickers hardness and Rockwell hardness, which are typically used to measure the hardness of bulk alloys, cannot be used to measure the hardness of thin films. Therefore, an Agilent Technologies Nano Indenter G200 nanoindenter was used in continuous stiffness mode to measure the hardness of Ta... 21 Hf 17 W 31 N 31 The hardness of the nitride film was tested, and the results showed that Ta 21 Hf 17 W 31 N 31 The nano-indentation hardness of the nitride film is 31.3 GPa and the elastic modulus is 340.5 GPa, making it suitable for applications in high-hardness and wear-resistant fields.

[0066] Example 2:

[0067] A method for preparing a high-hardness Ta-Hf-W nitride thin film, specifically Ta 20 Hf8W 30 N 42 The method for preparing nitride thin films includes the following steps:

[0068] Commercial P-type, crystal orientation <100> The single-crystal silicon wafer was treated with damped polishing, and then ultrasonically cleaned in anhydrous ethanol at a frequency of 60-80 Hz for 10 min to remove impurities and contaminants attached to the substrate surface. Next, the substrate was rinsed with deionized water and then dried with compressed nitrogen to prevent surface water residue. The substrate was fixed face down on the furnace tray, which was then fixed to the sample stage of the magnetron sputtering thin film deposition system. The sample stage baffle was rotated to completely cover the substrate. Metal targets Ta, Hf, and W were placed sequentially on three different DC target positions in the deposition chamber. The angle of each metal target perpendicular to the center line of the sample stage was adjusted to 30°, and the vertical distance between the metal targets and the sample stage was adjusted to 10 cm. The deposition chamber was first evacuated to less than 8.0 Pa using a mechanical pump, and then the vacuum level was reduced to less than 6.0 × 10⁻⁶ Pa using a molecular pump. -4 Pa; High-purity argon gas (≥99.999%) with a purity of ≥99.999% was introduced into the deposition chamber at a flow rate of 32 sccm, and high-purity nitrogen gas (≥99.999%) with a purity of ≥99.999% was introduced at a flow rate of 8 sccm. The working pressure was set to 0.7 Pa, and the sputtering power of the Ta target, Hf target, and W target was set to 100 W. The targets were pre-sputtered for 10 min to remove oxides and other impurities adhering to the target surface. After pre-sputtering, the sample stage rotation speed was set to 15 r / min, the sample stage baffle was opened, and formal sputtering began for 1 h. After sputtering, the DC constant current power supply and argon gas switch were turned off, the sample stage rotation was stopped, and the film was allowed to cool to room temperature under vacuum before being removed to reduce oxidation contamination. Finally, the Ta film was obtained on the silicon wafer. 20 Hf8W 30 N 42 Nitride thin films.

[0069] The chemical composition of the nitride film was analyzed using an Oxford X-act energy-dispersive X-ray spectroscopy (EDS, mounted on a scanning electron microscope). The surface and cross-sectional morphology SEM images and elemental surface scanning EDS spectra of the nitride film are attached. Figure 5 and 6 As shown: According to the quantitative calculation results of the software, the composition of this alloy film is Ta. 20 Hf8W 30 N 42 .

[0070] Ta was imaged using a Dimension ICON atomic force microscope (AFM) from Bruker GmbH, Germany. 20 Hf8W 30 N 42The surface morphology of the nitride film was analyzed using tapping mode, with a scan area of ​​10 μm × 10 μm. The surface roughness (Ra) of the film was analyzed using NanoScope Analysis software. The results are attached. Figure 7 Shown:Ta 20 Hf8W 30 N 42 The surface AFM morphology of the nitride film is needle-like, and the surface roughness is 1.85 nm.

[0071] Ta was analyzed using a D8 Advance X-ray diffractometer (XRD) from BRUKER AXS GmbH, Germany. 20 Hf8W 30 N 42 XRD phase analysis was performed on the nitride thin film. The operating voltage was 40 kV, the operating current was 40 mA, the X-ray source was Cu-Ka (λ = 0.15418 nm), the grazing incidence angle was 1°, the scanning speed was 4° / min, the scanning step size was 0.02° / step, and the scanning range was 10°–90°. The results are attached. Figure 8 As shown. Based on the extinction rules of lattice diffraction, the five diffraction peaks marked with black rhombuses in the spectrum can be determined to correspond to the (111), (200), (220), (311), and (222) crystal planes of the FCC structure phase, indicating that Ta 20 Hf8W 30 N 42 The crystal structure of the nitride film is a single-phase face-centered cubic (FCC) structure.

[0072] Because thin films are micro- and nano-scale materials, their hardness can only be measured using a nanoindenter. Vickers hardness and Rockwell hardness, which are typically used to measure the hardness of bulk alloys, cannot be used to measure the hardness of thin films. Therefore, an Agilent Technologies Nano Indenter G200 nanoindenter was used in continuous stiffness mode to measure the hardness of Ta... 20 Hf8W 30 N 42 The hardness of the nitride film was tested, and the results showed that Ta 20 Hf8W 30 N 42 The nanoindentation hardness of the nitride film is 36.1 GPa, and the elastic modulus is 357.2 GPa.

[0073] Example 3:

[0074] A method for preparing a high-hardness Ta-Hf-W nitride thin film, specifically Ta 17 Hf7W 29 N 47 The method for preparing nitride thin films includes the following steps:

[0075] Commercial P-type, crystal orientation <100> The single-crystal silicon wafer was treated with damped polishing, and then ultrasonically cleaned in anhydrous ethanol at a frequency of 60-80 Hz for 10 min to remove impurities and contaminants attached to the substrate surface. Next, the substrate was rinsed with deionized water and then dried with compressed nitrogen to prevent surface water residue. The substrate was fixed face down on the furnace tray, which was then fixed to the sample stage of the magnetron sputtering thin film deposition system. The sample stage baffle was rotated to completely cover the substrate. Metal targets Ta, Hf, and W were placed sequentially on three different DC target positions in the deposition chamber. The angle of each metal target perpendicular to the center line of the sample stage was adjusted to 30°, and the vertical distance between the metal targets and the sample stage was adjusted to 10 cm. The deposition chamber was first evacuated to less than 8.0 Pa using a mechanical pump, and then the vacuum level was reduced to less than 6.0 × 10⁻⁶ Pa using a molecular pump. -4 Pa; High-purity argon gas (≥99.999%) with a flow rate of 24 sccm and high-purity nitrogen gas (≥99.999%) with a flow rate of 16 sccm were introduced into the deposition chamber. The working pressure was set to 0.7 Pa. The sputtering power of the Ta target, Hf target, and W target was set to 100 W. The targets were pre-sputtered for 10 min to remove oxides and other impurities adhering to the target surface. After pre-sputtering, the sample stage rotation speed was set to 15 r / min, the sample stage baffle was opened, and formal sputtering began for 1 h. After sputtering, the DC constant current power supply and argon gas switch were turned off, the sample stage rotation was stopped, and the film was allowed to cool to room temperature under vacuum before being removed to reduce oxidation contamination. Finally, the Ta film was obtained on the silicon wafer. 17 Hf7W 29 N 47 Nitride thin films.

[0076] The chemical composition of the nitride film was analyzed using an Oxford X-act energy-dispersive X-ray spectroscopy (EDS, mounted on a scanning electron microscope). The surface and cross-sectional morphology SEM images and elemental surface scanning EDS spectra of the nitride film are attached. Figure 9 and 10 As shown: According to the quantitative calculation results of the software, the composition of this nitride film is Ta. 17 Hf7W 29 N 47 .

[0077] Ta was imaged using a Dimension ICON atomic force microscope (AFM) from Bruker GmbH, Germany. 17 Hf7W 29 N 47The surface morphology of the nitride film was analyzed using tapping mode, with a scan area of ​​10 μm × 10 μm. The surface roughness (Ra) of the film was analyzed using NanoScope Analysis software. The results are attached. Figure 11 Shown:Ta 17 Hf7W 29 N 47 The surface AFM morphology of the nitride film is needle-like, and the surface roughness is 2.06 nm.

[0078] Ta was analyzed using a D8 Advance X-ray diffractometer (XRD) from BRUKER AXS GmbH, Germany. 17 Hf7W 29 N 47 XRD phase analysis was performed on the nitride thin film. The operating voltage was 40 kV, the operating current was 40 mA, the X-ray source was Cu-Ka (λ = 0.15418 nm), the grazing incidence angle was 1°, the scanning speed was 4° / min, the scanning step size was 0.02° / step, and the scanning range was 10°–90°. The results are attached. Figure 12 As shown. Based on the extinction rules of lattice diffraction, the five diffraction peaks marked with black rhombuses in the spectrum can be determined to correspond to the (111), (200), (220), (311), and (222) crystal planes of the FCC structure phase, indicating that Ta 17 Hf7W 29 N 47 The crystal structure of the nitride film is a single-phase face-centered cubic (FCC) structure.

[0079] Because thin films are micro- and nano-scale materials, their hardness can only be measured using a nanoindenter. Vickers hardness and Rockwell hardness, which are typically used to measure the hardness of bulk alloys, cannot be used to measure the hardness of thin films. Therefore, an Agilent Technologies Nano Indenter G200 nanoindenter was used in continuous stiffness mode to measure the hardness of Ta... 17 Hf7W 29 N 47 The hardness of the nitride film was tested, and the results showed that Ta 17 Hf7W 29 N 47 The nanoindentation hardness of the nitride film is 28.4 GPa and the elastic modulus is 308.3 GPa, making it suitable for applications in high-hardness and wear-resistant fields.

[0080] Comparative example:

[0081] The method for preparing Ta-Hf-W nitride thin films includes the following steps: preparing Ta-Hf-W nitride thin films at a nitrogen flow rate of 50%:

[0082] The commercial P-type single crystal silicon wafer with <100> crystal orientation is treated by damping polishing, then cleaned in anhydrous ethanol for 10 minutes under ultrasonic wave with a frequency of 60-80 Hz to remove impurities and contaminants attached to the surface of the substrate, then the substrate is rinsed with deionized water and dried with compressed nitrogen to prevent the residual of water stains on the surface; the smooth surface of the substrate is fixed on a furnace plate, and the furnace plate is fixed on a sample table of a deposition chamber of a magnetron sputtering thin film deposition system device, and a sample table shutter is adjusted to completely cover the substrate; metal targets of Ta, Hf and W are placed in three different direct current target positions of the deposition chamber respectively, and the angle of each metal target perpendicular to the center line of the sample table is adjusted to 30°, and the vertical distance between the metal target and the sample table is adjusted to 10 cm; the deposition chamber is first pumped to a vacuum degree less than 8.0 Pa by a mechanical pump, and then pumped to a vacuum degree less than 6.0 × 10 -4 Pa by a molecular pump; high-purity argon gas with a purity of ≥99.999% and a flow rate of 20 sccm and high-purity nitrogen gas with a purity of ≥99.999% and a flow rate of 20 sccm are introduced into the deposition chamber, the working gas pressure is set to 0.7 Pa, the sputtering power of the Ta target is set to 100 W, the sputtering power of the Hf target is set to 100 W, and the sputtering power of the W target is set to 100 W, and the target is pre-sputtered for 10 minutes to remove impurities such as oxides attached to the surface of the target; after the pre-sputtering is completed, the rotation rate of the sample table is set to 15 r / min, the sample table shutter is opened, and the formal sputtering is started for 1 hour; after the sputtering is completed, the direct current constant current power supply is turned off, the argon gas switch is turned off, the sample table rotation is stopped, and the thin film is cooled to room temperature in a vacuum state to reduce oxidation pollution, and finally the Ta-Hf-W nitride thin film prepared under the nitrogen flow rate of 50% is obtained on the silicon wafer.

[0083] Figure 13 The macroscopic morphology of the Ta-Hf-W nitride thin film prepared under the nitrogen flow rate of 50%.

[0084] It is shown that when the nitrogen flow rate is 50%, the Nb-Ta-W-N thin film surface cracks. The nitrogen content of the Nb-Ta-W-N thin film increases sharply with the increase of the nitrogen flow rate, and the nitrogen content rises to 47% when the nitrogen flow rate is 40% and reaches a saturation state. This indicates that the nitride thin film prepared under the process condition of the nitrogen flow rate of 50% should have the maximum residual stress, which causes the thin film to crack.

[0085] The properties of the Ta-Hf-W nitride thin film obtained in the examples and comparative examples are shown in Table 1.

[0086] Table 1

[0087] Surface roughness Hardness Elastic modulus Example 1 2.20 nm 31.3 GPa 340.5 GPa Example 2 1.85 nm 36.1 GPa 357.2 Gpa Example 3 2.06 nm 28.4 GPa 308.3 Gpa Comparative Example / / /

[0088] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A high hardness Ta-Hf-W nitride film, characterized by: is Ta a Hf b W c N d nitride film, the nitride film is composed of Ta, Hf, W, N atoms, and the chemical formula is: Ta a Hf b W c N d ; wherein, a, b, c and d all represent atomic ratio, the value range of a is: 17~21; the value range of b is: 7~17; the value range of c is: 29~31; the value range of d is: 31~47, and a+b+c+d =100; the Ta, Hf, W target material is prepared by the method of reactive magnetron sputtering film deposition with the set sputtering power and the set different nitrogen gas flow, and the Ta a Hf b W c N d nitride film; the component number of the nitride film is four, has single-phase face-centered cubic crystal structure, the surface roughness is 1.85~2.20 nm, the hardness of the film is 28.4~36.1 GPa, and the elastic modulus is 308.3~357.2 GPa.

2. The method of claim 1, wherein the high hardness Ta-Hf-W nitride film is prepared by the steps of: depositing a Ta-Hf-W film on a substrate; and annealing the Ta-Hf-W film at a temperature of 500°C to 700°C in a nitrogen atmosphere. The method comprises the following steps: 1) ultrasonic cleaning the substrate in anhydrous ethanol for 10 min at an ultrasonic frequency of 60-80 Hz to remove contaminants attached to the surface of the substrate, and then rinsing the substrate with deionized water; the substrate is a single crystal silicon wafer, the single crystal silicon wafer is commercially available P-type, and the crystal direction is <100>; 2) drying the cleaned substrate with compressed nitrogen to keep the surface of the substrate clean and prevent water stains from remaining; 3) fixing the substrate with the smooth surface facing down on a furnace plate, fixing the furnace plate on a sample stage of a deposition chamber of a magnetron sputtering thin film deposition device, and rotating a sample stage baffle to the position of completely covering the substrate; 4) placing Ta, Hf and W metal block targets on three different direct current target positions of the deposition chamber respectively, adjusting the angle of each target perpendicular to the center line of the sample stage and the vertical distance between each target and the sample stage; the Ta, Hf and W targets are all high-purity metal blocks with a purity of ≥99.95 %, a diameter of 60 mm and a thickness of 3-5 mm; the angle of the target relative to the center line of the sample stage is 20-40°; the vertical distance between the Ta, Hf and W metal targets and the sample stage is 5-15 cm; 5) first using a mechanical pump to evacuate the deposition chamber to less than 8.0 Pa, and then using a molecular pump to evacuate the deposition chamber to less than 6.0 x 10 -4 8.0 x 10 -4 Pa; 6) then introducing argon and nitrogen into the deposition chamber, adjusting the flow rates of the introduced gases respectively, adjusting the working gas pressure to 0.7-0.9 Pa, turning on the direct current power supply of the corresponding target, setting the sputtering power of the target respectively, and pre-sputtering the target for 10-15 min to remove the oxide impurities formed on the surface of the target, wherein the sputtering power of the Ta target is 100 W, the sputtering power of the Hf target is 100 W, and the sputtering power of the W target is 100 W; the total gas flow rate of argon and nitrogen is 40 sccm and remains unchanged, wherein the gas flow rate of nitrogen is 4-16 sccm, and nitrogen accounts for 10%-40% of the total gas flow rate; accordingly, the gas flow rate of argon is 24-36 sccm, and the purity of the two gases is ≥99.999 %; 7) setting the rotation rate of the sample stage to 15-30 r / min, opening the substrate baffle, and performing sputter deposition on the smooth surface of the substrate after opening the substrate baffle, and the sputtering time is 1 h to obtain a thin film; 8) After the sputtering deposition is completed, the direct current power is turned off, the argon and nitrogen are turned off, the sample table rotation is stopped, the film is cooled to room temperature in a vacuum state, and then taken out, so as to reduce oxidation pollution, and finally a Ta a Hf b W c N d The nitride film is a high-hardness Ta-Hf-W nitride film, which is composed of Ta, Hf, W and N atoms, and is expressed as Ta a Hf b W c N d ; wherein a, b, c and d all represent atomic ratios, the value range of a is 17-21, the value range of b is 7-17, the value range of c is 29-31, the value range of d is 31-47, and a+b+c+d = 100; the component number of the nitride film is four, has a single-phase face-centered cubic crystal structure, the surface roughness is 1.85-2.20 nm, the hardness of the film is 28.4-36.1 GPa, and the elastic modulus is 308.3-357.2 GPa.

3. The method of claim 2, wherein the Ta-Hf-W nitride film has a hardness of at least 30 GPa. in step 1), the smooth surface of the substrate is polished with a damping cloth before ultrasonic cleaning.

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