Titanium nitride composite film and preparation method and application thereof

Abstract

The invention relates to a titanium nitride composite film and a preparation method and application thereof.The preparation method comprises the following steps that S1, a carbon-based base material is subjected to magnetron sputtering in an inert gas atmosphere to deposit a titanium layer, and the magnetron sputtering time is 5-60 min; and S2, nitrogen is intermittently introduced to serve as reaction gas to continue magnetron sputtering, a titanium nitride layer is deposited on the titanium layer, and the volume flow of the nitrogen is controlled to be smaller than or equal to 20 SCCM. According to the method, firstly, a titanium layer is deposited on the surface of a carbon-based base material to serve as a buffer layer, nitrogen atoms are prevented from being singly crystallized into titanium nitride crystal lattices in the titanium nitride crystallization process by controlling nitrogen partial pressure in a reaction system, and therefore internal stress generated by titanium nitride crystallization is reduced; and along with the addition of nitrogen, a C-Ti-N bond can be formed at the interface, so that the bonding force between the titanium nitride composite film and the interface of the carbon-based substrate is further increased, and the ablativity of the carbon-based substrate is improved.

Description

Technical Field

[0001] The present application relates to the field of film coating technology, and in particular to a titanium nitride composite film and a preparation method and application thereof. Background Art

[0002] Titanium nitride is a face-centered cubic crystal material with a high melting point (3000°C) and high hardness (Vickers microhardness of 20GPa). Titanium nitride film is often used as a corrosion-resistant layer or barrier layer in many fields due to its good toughness, wear resistance, conductivity and chemical stability. It is also often used as an electrode material in the field of electronic devices. The conventional method for preparing titanium nitride thin films usually adopts magnetron sputtering, which deposits titanium nitride films by introducing nitrogen into the chamber of a magnetron sputtering device with titanium metal as the target. This method of preparing titanium nitride films has the characteristics of fast deposition rate and good uniformity of deposited films, but it has high requirements on the material of the substrate and can usually only be used in conjunction with metal substrates.

[0003] Metal substrates are easy to melt at high temperatures, while carbon-based substrates are not only resistant to high temperatures, but also widely available and low cost, so they are widely used in the field of semiconductor material preparation. For example, graphite or carbon powder is required to prepare silicon carbide single crystals. However, the current carbon-based substrates used in the semiconductor field have a short thermal cycle life and their ablation resistance needs to be improved. Summary of the invention

[0004] Based on this, it is necessary to provide a titanium nitride composite film and a preparation method and application thereof to improve the ablation resistance of a carbon-based substrate.

[0005] The first aspect of the present application provides a method for preparing a titanium nitride composite film, comprising the following steps:

[0006] S1: depositing a titanium layer on a carbon-based substrate by magnetron sputtering in an inert gas atmosphere, wherein the magnetron sputtering time is 5 min to 60 min;

[0007] S2: Then, nitrogen gas is intermittently introduced as a reaction gas to continue magnetron sputtering to deposit a titanium nitride layer on the titanium layer, and the volume flow rate of the nitrogen gas is controlled to be less than or equal to 20 SCCM.

[0008] In the above preparation method, a titanium layer is first deposited on the surface of the carbon-based substrate as a buffer layer to buffer the difference in thermal expansion coefficient between the titanium nitride composite film and the carbon-based substrate. At the same time, the titanium layer can also improve the chemical compatibility between the titanium nitride composite film and the carbon-based substrate, thereby improving the interface bonding strength between the titanium nitride composite layer and the carbon-based substrate; and the initial sputtering time is controlled within 5 min to 60 min, which can well balance the buffering effect and interface bonding strength of the titanium layer; when depositing the titanium nitride layer, the above preparation method controls the amount of nitrogen introduced by intermittently introducing nitrogen, and controls the volume flow rate of nitrogen to be less than or equal to 20 SCCM, which not only avoids the nitrogen enrichment phenomenon in the titanium nitride layer and reduces the coating bonding strength, but also makes the molar content of nitrogen atoms in the titanium nitride layer lower than the molar content of titanium atoms, thereby making the crystal structure of the titanium nitride layer have Ti-Ti-N-Ti-Ti bonds due to the insufficient number of nitrogen atoms, instead of all Ti-N-Ti-N-Ti bonds, so that The nitrogen atoms are prevented from crystallizing into a single titanium nitride lattice with a face-centered cubic crystal structure during the titanium nitride crystallization process, thereby promoting stress release, reducing the internal stress generated by titanium nitride crystallization, and enhancing the interface bonding strength; at the same time, due to the buffering of the aforementioned pure titanium layer, the interface closest to the carbon-based substrate can form a C-Ti-N bond at the interface closest to the carbon-based substrate with the addition of nitrogen, further increasing the interface bonding strength between the titanium nitride composite film and the carbon-based substrate, making the titanium nitride composite film not easy to fall off under high temperature or corrosive conditions, forming a barrier layer for the carbon-based substrate to the outside, and ultimately greatly improving the ablation resistance of the carbon-based substrate.

[0009] When the carbon-based substrate with the titanium nitride composite film is used to prepare semiconductor materials such as silicon carbide single crystals, the obtained semiconductor material has excellent performance, and has excellent high temperature resistance, ablation resistance and electrical properties.

[0010] The titanium nitride composite film prepared by the preparation method has a fast deposition speed, good uniformity, strong toughness, wear resistance, conductivity and chemical stability. The preparation method is simple and fast to operate, improves the coating efficiency and reduces the production cost.

[0011] In some embodiments, in S2, the intermittent introduction of nitrogen comprises the following steps:

[0012] The nitrogen flow rate is 0.1 SCCM~20 SCCM. After the reaction time is 0.5h~6h, the nitrogen flow is stopped for 5min~60min.

[0013] Then, nitrogen gas with a flow rate of 0.1 SCCM to 20 SCCM was introduced, and magnetron sputtering was stopped after reacting for 0.5 h to 10 h.

[0014] In some embodiments, after the reaction for 0.5h to 10h and before the magnetron sputtering is stopped, the following steps are also included:

[0015] Stop the nitrogen flow for 5 min to 60 min, then continue to flow nitrogen at a flow rate of 0.1 SCCM to 20 SCCM for 0.5 h to 10 h.

[0016] In some embodiments, during the period when the nitrogen gas is introduced at a flow rate of 0.1 SCCM to 20 SCCM, the partial pressure of the nitrogen gas accounts for 6% to 15% of the coating pressure.

[0017] In some embodiments, the method for preparing the titanium nitride composite film satisfies at least one of the following conditions:

[0018] (1) The thickness of the titanium nitride composite film is 10 μm to 100 μm;

[0019] (2) The carbon-based substrate comprises at least one of graphite, carbon / carbon composite materials, diamond-like carbon, carbon nanotubes and graphene;

[0020] (3) The carbon-based substrate rotates at a rotation speed of 0.5 r / min to 8 r / min.

[0021] In some embodiments, S1 satisfies at least one of the following conditions:

[0022] (1) The magnetron sputtering time is 5 min to 40 min;

[0023] (2) before performing the magnetron sputtering, heating the carbon-based substrate to 200° C. to 500° C.;

[0024] (3) Heat the target to 25°C~250°C;

[0025] (4) The inert gas is argon gas, and the flow rate of the argon gas is 25 SCCM to 200 SCCM;

[0026] (5) The starting pressure is 2×10 -3 Pa~9×10 -3 Pa.

[0027] In some embodiments, the method for preparing the titanium nitride composite film further comprises the following steps: subjecting the carbon-based substrate coated with the titanium nitride composite film to vacuum annealing treatment at a temperature of 450° C. to 900° C. for 0.5 h to 10 h.

[0028] In some embodiments, in S2, the power of the magnetron sputtering is 1KW~50KW; and / or the coating pressure is 5×10 -3 Pa~8×10 -3 Pa; and / or, the magnetron sputtering time is 1.5 h ~28 h.

[0029] A second aspect of the present application provides a titanium nitride composite film, which is prepared by the method for preparing the titanium nitride composite film as described in the first aspect.

[0030] The third aspect of the present application provides a semiconductor material, comprising the titanium nitride composite film as described in the second aspect. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant embodiments, and preferred embodiments of the present invention are given in the text. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] Titanium nitride has good toughness, wear resistance, conductivity and chemical stability, so it is often used as a corrosion-resistant layer or barrier layer, but titanium nitride has a high thermal expansion coefficient (higher than tantalum carbide) and has high requirements for the substrate material. It is difficult to use it to prepare titanium nitride films on carbon-based substrates with low thermal expansion coefficients. Titanium nitride is easily cracked and detached when plated on carbon-based substrates, which greatly limits the application of titanium nitride in the field of film coating. In addition, carbon-based substrates are widely used in the field of semiconductor material preparation due to their high temperature resistance, wide sources and low cost, but the current carbon-based substrates used in the semiconductor field have short thermal cycle life and low ablation resistance. This application pioneered the magnetron sputtering of titanium nitride composite films on carbon-based substrates, and solved the above-mentioned technical problems from the perspective of enhancing the interfacial bonding between the titanium nitride composite film and the carbon-based substrate.

[0034] Based on this, an embodiment of the present application provides a method for preparing a titanium nitride composite film, comprising the following steps:

[0035] S1: depositing a titanium layer on a carbon-based substrate by magnetron sputtering in an inert gas atmosphere, wherein the magnetron sputtering time is 5 min to 60 min;

[0036] S2: Then, nitrogen gas is intermittently introduced as a reaction gas to continue magnetron sputtering to deposit a titanium nitride layer on the titanium layer, and the volume flow rate of the nitrogen gas is controlled to be less than or equal to 20 SCCM.

[0037] In the above preparation method, a titanium layer is first deposited on the surface of the carbon-based substrate as a buffer layer to buffer the difference in thermal expansion coefficient between the titanium nitride composite film and the carbon-based substrate. At the same time, the titanium layer can also improve the chemical compatibility between the titanium nitride composite film and the carbon-based substrate, thereby improving the interface bonding strength between the titanium nitride composite layer and the carbon-based substrate; and the initial sputtering time is controlled within 5 min to 60 min, which can well balance the buffering effect and interface bonding strength of the titanium layer; when depositing the titanium nitride layer, the above preparation method controls the amount of nitrogen introduced by intermittently introducing nitrogen, and controls the volume flow rate of nitrogen to be less than or equal to 20 SCCM, which not only avoids the nitrogen enrichment phenomenon in the titanium nitride layer and reduces the coating bonding strength, but also makes the molar content of nitrogen atoms in the titanium nitride layer lower than the molar content of titanium atoms, thereby making the crystal structure of the titanium nitride layer have Ti-Ti-N-Ti-Ti bonds due to the insufficient number of nitrogen atoms, instead of all Ti-N-Ti-N-Ti bonds, so that The nitrogen atoms are prevented from crystallizing into a single titanium nitride lattice with a face-centered cubic crystal structure during the titanium nitride crystallization process, thereby promoting stress release, reducing the internal stress generated by titanium nitride crystallization, and enhancing the interface bonding strength; at the same time, due to the buffering of the aforementioned pure titanium layer, the interface closest to the carbon-based substrate can form a C-Ti-N bond at the interface closest to the carbon-based substrate with the addition of nitrogen, further increasing the interface bonding strength between the titanium nitride composite film and the carbon-based substrate, making the titanium nitride composite film not easy to fall off under high temperature or corrosive conditions, forming a barrier layer for the carbon-based substrate to the outside, and ultimately greatly improving the ablation resistance of the carbon-based substrate.

[0038] When the carbon-based substrate with the titanium nitride composite film is used to prepare semiconductor materials such as silicon carbide single crystals, the obtained semiconductor material has excellent performance, and has excellent high temperature resistance, ablation resistance and electrical properties.

[0039] The titanium nitride composite film prepared by the preparation method has a fast deposition speed, good uniformity, strong toughness, wear resistance, conductivity and chemical stability. The preparation method is simple and fast to operate, improves the coating efficiency and reduces the production cost.

[0040] As an example, the magnetron sputtering time in S1 can be 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min, 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min, 29min, 30min, 31min, 32min, 33min, 34min, 35min, 36min, 37min, 38min, 39min, 40min, 41min, 42min, 43min, 44min, 45min, 46min, 47min, 48min, 49min, 50min, 51min, 52min, 53min, 54min, 55min, 56min, 57min, 58min, 59min and 60min, or it can be within the range formed by any two of the above point values ​​as end values. Preferably it is 5 min to 40 min, more preferably 20 min to 40 min.

[0041] In some embodiments, the carbon-based substrate includes at least one of graphite, carbon / carbon composite materials, diamond-like carbon, carbon nanotubes, and graphene.

[0042] Furthermore, the carbon-based substrate includes a film formed from one or more of graphite, carbon / carbon composite materials, diamond-like carbon, carbon nanotubes and graphene, and can be a single film or a stack of multiple films.

[0043] In some embodiments, the target material used in magnetron sputtering is a titanium target.

[0044] In some embodiments, before magnetron sputtering, the carbon-based substrate is first cleaned with anhydrous ethanol or ultrasonically cleaned with water and then dried.

[0045] Furthermore, the cleaned carbon-based substrate was baked in an oven in a nitrogen atmosphere for 30 minutes at a baking temperature of 100°C.

[0046] In some of the embodiments, the magnetron sputtering is performed in a magnetron sputtering coater.

[0047] In some of the embodiments, after the carbon-based substrate is evenly distributed on the magnetron sputtering support, the support is placed in a vacuum chamber of a magnetron sputtering coating machine equipped with a titanium target, and the vacuum pump group is turned on to evacuate the vacuum chamber.

[0048] In some embodiments, in S1, before performing the magnetron sputtering, the carbon-based substrate is heated to 200° C. to 500° C. and / or the titanium target is heated to 25° C. to 250° C. The carbon-based substrate and the titanium target are heated in a vacuum chamber of a magnetron sputtering coating machine.

[0049] In some embodiments, in S1, the inert gas is argon, and the argon flow rate is 25 SCCM to 200 SCCM; and / or the ignition pressure is 2×10 -3 Pa~9×10 -3 Pa. Argon gas was introduced to control the ignition pressure of the vacuum chamber at 2×10 -3 Pa~9×10 -3 Pa.

[0050] In some embodiments, the carbon-based substrate is rotated at a rotation speed of 0.5 r / min to 8 r / min. The rotation speed of the carbon-based substrate is controlled by controlling the rotation speed of the magnetron sputtering support.

[0051] In some embodiments, in S1, the power of the magnetron sputtering power source is 1KW~50KW.

[0052] In some embodiments, in S1, the sputtering time is 5 min to 40 min. By controlling the initial sputtering time of the titanium layer to 5 min to 40 min, a good interface structure can be obtained, further improving the bonding strength between the titanium nitride composite film and the carbon-based substrate. After the sputtering of the titanium layer, the buffer layer, is completed, a nitrogen atmosphere needs to be introduced in time.

[0053] In some embodiments, in S2, the power of the magnetron sputtering power source is 1KW~50KW.

[0054] In some embodiments, in S2, the coating pressure is 5×10 -3 Pa~8×10 -3 Pa.

[0055] In some embodiments, in S2, the intermittent introduction of nitrogen comprises the following steps:

[0056] The nitrogen flow rate is 0.1 SCCM~20 SCCM. After the reaction time is 0.5h~6h, the nitrogen flow is stopped for 5min~60min.

[0057] Then, nitrogen gas with a flow rate of 0.1 SCCM to 20 SCCM is introduced, and magnetron sputtering is stopped after the reaction for 0.5 h to 10 h. In this way, nitrogen gas is introduced intermittently. As the nitrogen content changes, a mixed phase structure will be formed during the crystallization of titanium nitride, thereby further reducing the internal stress generated by titanium nitride crystallization and avoiding stress concentration. Even if the titanium nitride composite film is under the action of cutting force and thermal stress, it is not easy to fall off.

[0058] In some embodiments, after the reaction for 0.5h to 10h and before the magnetron sputtering is stopped, the following steps are also included:

[0059] Stop the nitrogen flow for 5 min to 60 min, then continue to flow nitrogen at a flow rate of 0.1 SCCM to 20 SCCM for 0.5 h to 10 h.

[0060] In some embodiments, the intermittent introduction of nitrogen comprises the following steps:

[0061] The nitrogen flow rate is 0.1 SCCM~20 SCCM. After the reaction time is 0.5h~6h, the nitrogen flow is stopped for 5min~60min.

[0062] Then, nitrogen gas was introduced at a flow rate of 0.1 SCCM to 20 SCCM. After the reaction lasted for 0.5 h to 10 h, the introduction of nitrogen gas was stopped for 5 min to 60 min.

[0063] Then, nitrogen gas with a flow rate of 0.1 SCCM to 20 SCCM is introduced for 0.5 h to 10 h of reaction, and then the sputtering is stopped. In this way, intermittent introduction of nitrogen gas can further reduce the internal stress generated by the titanium nitride crystal, so that the titanium nitride composite film has a lower ablation rate and a longer average thermal cycle life.

[0064] Furthermore, during the period of introducing nitrogen gas with a flow rate of 0.1 SCCM to 20 SCCM, the partial pressure of the nitrogen gas accounts for 6% to 15% of the coating pressure.

[0065] The definition of coating pressure refers to the gas pressure environment maintained in the sputtering chamber during the magnetron sputtering process, which is the pressure generated by the thermal motion of the gas molecules in the chamber on the chamber wall and the surface of the internal objects.

[0066] As an example, during the period when the nitrogen gas with a flow rate of 0.1SCCM to 20SCCM is introduced, the partial pressure of the nitrogen gas accounts for 6%, 6.5%, 7%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13.0%, 13.5%, 14.0%, 14.5% and 15% of the coating pressure, and can also be within the range formed by any two of the above point values ​​as end values. The partial pressure of the nitrogen gas preferably accounts for 8% to 10% of the coating pressure. Controlling the partial pressure of the nitrogen gas at 8% to 10% of the coating pressure is more conducive to making the molar ratio of titanium atoms to nitrogen atoms at the interface closest to the carbon-based substrate 1:1, thereby forming more C-Ti-N bonds at the interface, further enhancing the bonding strength between the titanium nitride composite film and the carbon-based substrate.

[0067] In some embodiments, the thickness of the titanium nitride composite film is 10 μm to 100 μm. When the thickness of the titanium nitride composite film is 10 μm to 100 μm, the titanium nitride composite film has outstanding appearance performance, no cracks, higher film layer bonding strength, and lower ablation rate.

[0068] As an example, the thickness of the titanium nitride composite film can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm and 100 μm, or can be within the range formed by any two of the above point values ​​as end values. Preferably, 20 μm to 50 μm.

[0069] In some of the embodiments, after the titanium nitride composite film coating is completed, the vacuum pump group of the magnetron sputtering coating machine is turned off, and the carbon-based substrate coated with the titanium nitride composite film is taken out after the inner pressure of the vacuum chamber and the atmospheric pressure are balanced and the temperature of the vacuum chamber drops below 50°C.

[0070] In some embodiments, the following steps are also included: annealing the carbon-based substrate coated with the titanium nitride composite film at a temperature of 450°C to 900°C and under vacuum conditions for 0.5h to 10h. The annealing treatment can further eliminate the stress inside the material and at the bonding interface, and improve the interface bonding strength and anti-ablation performance.

[0071] In some embodiments, in S1, the sputtering time is 5 min to 40 min.

[0072] In some embodiments, in S2, the sputtering time is 1.5h to 28h.

[0073] A second aspect of the present application provides a titanium nitride composite film, which is prepared by the method for preparing the titanium nitride composite film as described in the first aspect.

[0074] The third aspect of the present application provides a refractory product, comprising the titanium nitride composite film as described in the second aspect.

[0075] The following are specific embodiments.

[0076] Example 1

[0077] A method for preparing a titanium nitride composite film comprises the following steps:

[0078] Step 1: The graphite substrate is ultrasonically cleaned with anhydrous ethanol and water and dried, and the cleaned graphite substrate is placed in an oven in a nitrogen atmosphere and baked for 30 minutes at a baking temperature of 100°C.

[0079] Step 2: After the graphite substrate is evenly distributed on the magnetron sputtering bracket, the bracket is placed in the vacuum chamber of the magnetron sputtering coater equipped with a titanium target, the vacuum pump group is turned on to evacuate the vacuum chamber, and the graphite substrate on the bracket is heated to 450°C, and the target temperature is heated to 100°C. Among them, the magnetron sputtering coater adopts the PVD850-DLC coating system.

[0080] Step 3: Introduce 100 SCCM of argon gas to control the starting pressure of the vacuum chamber at 7×10 -3 Pa, wait for the titanium target to start sputtering for 20 minutes to perform the initial sputtering deposition of the titanium layer; after the titanium layer is deposited, 6SCCM nitrogen is introduced as the reaction gas, the magnetron sputtering power supply is adjusted to 5KW, the bracket rotation speed is 2.5r / min, the magnetron sputtering treatment time is 2h, and then the nitrogen flow rate is set to 0SCCM, and the reaction continues for 0.5h; the nitrogen flow rate is set to 6SCCM, the reaction is 3h, and then the nitrogen flow rate is set to 0SCCM, and the reaction is continued for 0.5h, and finally the nitrogen flow rate is set to 6SCCM for 4h before stopping sputtering and depositing the titanium nitride layer. Among them, during the deposition of the titanium nitride layer, the coating pressure is 7×10 -3 Pa, the nitrogen partial pressure during the nitrogen introduction is 10% of the coating pressure.

[0081] Step 4: After coating, turn off the vacuum pump group of the magnetron sputtering coating machine, wait until the pressure in the vacuum chamber is balanced with the atmospheric pressure, and the temperature in the vacuum chamber drops below 50°C before taking out the substrate.

[0082] Step 5: annealing the graphite substrate coated with the titanium nitride composite film at 700° C. and vacuum for 2 h to prepare a graphite substrate coated with the titanium nitride composite film, wherein the thickness of the titanium nitride composite film is 30 μm.

[0083] Example 2

[0084] A method for preparing a titanium nitride composite film comprises the following steps:

[0085] Step 1: The graphite substrate is ultrasonically cleaned with anhydrous ethanol and water and dried, and the cleaned graphite substrate is placed in an oven in a nitrogen atmosphere and baked for 30 minutes at a baking temperature of 100°C.

[0086] Step 2: After the graphite substrate is evenly distributed on the magnetron sputtering bracket, the bracket is placed in the vacuum chamber of the magnetron sputtering coating machine equipped with a titanium target, the vacuum pump group is turned on to evacuate the vacuum chamber, and the graphite substrate on the bracket is heated to 450°C and the target temperature is heated to 100°C.

[0087] Step 3: Introduce 150 SCCM of argon gas to control the starting pressure of the vacuum chamber at 7×10 -3 Pa, after the titanium target was sputtered for 40 minutes, 10 SCCM nitrogen was introduced as the reaction gas, the magnetron sputtering power supply was adjusted to 8KW, the bracket rotation speed was 2.5r / min, the magnetron sputtering treatment time was 2h, and then the nitrogen flow rate was set to 0 SCCM, and the reaction continued for 0.5h; the nitrogen flow rate was set to 20 SCCM, and the reaction lasted for 3h, and then the nitrogen flow rate was set to 0 SCCM, and the reaction continued for 0.5h, and finally the nitrogen flow rate was set to 10 SCCM, and the reaction lasted for 4h before stopping the sputtering and depositing the titanium nitride layer. During the deposition of the titanium nitride layer, the coating pressure was 6×10 -3 Pa, the nitrogen partial pressure is 8% of the coating pressure.

[0088] Step 4: After the coating is completed, turn off the vacuum pump group of the magnetron sputtering coating machine, wait until the pressure in the vacuum chamber is balanced with the atmospheric pressure, and the temperature of the vacuum chamber drops below 50°C before taking out the substrate.

[0089] Step 5: The graphite substrate coated with the titanium nitride coating is annealed at 700° C. and vacuum for 2 h to prepare a graphite substrate coated with the titanium nitride coating, wherein the thickness of the titanium nitride composite film is 25 μm.

[0090] Example 3

[0091] Example 3 is basically the same as Example 1, except that in step 3, nitrogen is introduced after the titanium target is sputtered for 60 minutes.

[0092] Example 4

[0093] Example 4 is substantially the same as Example 1, except that diamond-like carbon is used instead of the graphite substrate.

[0094] Example 5

[0095] Example 5 is basically the same as Example 1, except that the thickness of the titanium nitride composite film is 100 μm.

[0096] Comparative Example 1

[0097] Comparative Example 1 is substantially the same as Example 1, except that in step 3, the magnetron sputtering time for depositing the titanium layer is 90 minutes.

[0098] Comparative Example 2

[0099] Comparative Example 2 is substantially the same as Example 1, except that in step 3, when depositing the titanium nitride layer, 25 SCCM nitrogen is continuously introduced as a reaction gas.

[0100] The carbon-based substrates coated with titanium nitride composite films prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were subjected to performance tests, and the test results are shown in Table 1 below.

[0101] Among them, the test conditions or test standards for each performance test item are as follows:

[0102] Appearance characteristics: direct observation.

[0103] Bonding strength test: According to the principle of impact test method, the impact energy generated by the impact tester is used to make the sample with titanium nitride coating be subjected to instantaneous impact force. The coating will deform, crack or even peel off under the impact load. The bonding strength is evaluated by observing the damage of the coating after the impact.

[0104] Ablation rate test: According to the principle of oxyacetylene flame ablation method, oxyacetylene flame is used to generate high temperature to simulate the ablation of titanium nitride coating in a high temperature environment. The ablation rate is calculated by measuring the mass change of the coating before and after ablation.

[0105] Table 1

[0106]

[0107] It can be seen from Table 1 above that the titanium nitride composite films of Examples 1 to 5 have high bonding strength with the carbon-based substrate and strong ablation resistance.

[0108] It can be seen from Comparative Examples 1 and 2 that if the time for the initial sputtering of the pure titanium coating is not within the scope of the present application or the intermittent nitrogen introduction method of the present application is not adopted, the technical effect of the present application cannot be achieved.

[0109] It can be seen from Examples 1 to 3 that when the time of the initial sputtering of the pure titanium coating is controlled to be between 5 min and 40 min, the bonding strength between the titanium nitride composite film and the carbon-based substrate is higher and the ablation resistance is better.

[0110] From the comparison between Example 1 and Example 5, it can be seen that when the thickness of the titanium nitride composite film is between 20 μm and 50 μm, the bonding strength between the titanium nitride composite film and the carbon-based substrate is higher and the ablation resistance is better.

[0111] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0112] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a titanium nitride composite film, characterized in that: The following steps are involved: S1: depositing a titanium layer on a carbon-based substrate by magnetron sputtering in an inert gas atmosphere, wherein the magnetron sputtering time is 5 min to 60 min; S2: Then, nitrogen gas is intermittently introduced as a reaction gas to continue magnetron sputtering to deposit a titanium nitride layer on the titanium layer, and the volume flow rate of the nitrogen gas is controlled to be less than or equal to 20 SCCM.

2. The method for preparing a titanium nitride composite film according to claim 1, characterized in that: In S2, the intermittent introduction of nitrogen comprises the following steps: The nitrogen flow rate is 0.1 SCCM~20 SCCM. After the reaction time is 0.5h~6h, the nitrogen flow is stopped for 5min~60min. Then, nitrogen gas with a flow rate of 0.1 SCCM to 20 SCCM was introduced, and magnetron sputtering was stopped after reacting for 0.5 h to 10 h.

3. The method for preparing the titanium nitride composite film according to claim 2, characterized in that: After the reaction for 0.5h to 10h and before the magnetron sputtering is stopped, the following steps are also included: Stop the nitrogen flow for 5 min to 60 min, then continue to flow nitrogen at a flow rate of 0.1 SCCM to 20 SCCM for 0.5 h to 10 h.

4. The method for preparing a titanium nitride composite film according to any one of claims 2 to 3, characterized in that: During the period of introducing nitrogen gas with a flow rate of 0.1 SCCM to 20 SCCM, the partial pressure of the nitrogen gas accounts for 6% to 15% of the coating pressure.

5. The method for preparing a titanium nitride composite film according to any one of claims 1 to 3, characterized in that: At least one of the following conditions is met: (1) The thickness of the titanium nitride composite film is 10 μm to 100 μm; (2) The carbon-based substrate comprises at least one of graphite, carbon / carbon composite materials, diamond-like carbon, carbon nanotubes and graphene; (3) The carbon-based substrate rotates at a rotation speed of 0.5 r / min to 8 r / min.

6. The method for preparing a titanium nitride composite film according to any one of claims 1 to 3, characterized in that: S1 satisfies at least one of the following conditions: (1) The magnetron sputtering time is 5 min to 40 min; (2) before performing the magnetron sputtering, heating the carbon-based substrate to 200° C. to 500° C.; (3) Heat the target to 25°C~250°C; (4) The inert gas is argon gas, and the flow rate of the argon gas is 25 SCCM to 200 SCCM; (5) The starting pressure is 2×10 -3 Pa~9×10 -3 Pa.

7. The method for preparing a titanium nitride composite film according to any one of claims 1 to 3, characterized in that: The following steps are also included: The carbon-based substrate coated with the titanium nitride composite film is subjected to vacuum annealing treatment at a temperature of 450° C. to 900° C. for 0.5 h to 10 h.

8. The method for preparing a titanium nitride composite film according to any one of claims 1 to 3, characterized in that: In S2, the power of the magnetron sputtering is 1KW~50KW; and / or the coating pressure is 5×10 -3 Pa~8×10 -3 Pa; and / or, the magnetron sputtering time is 1.5 h ~28 h.

9. A titanium nitride composite film, characterized in that: The titanium nitride composite film is prepared by the method for preparing the titanium nitride composite film according to any one of claims 1 to 8.

10. A semiconductor material, characterized in that: Comprising the titanium nitride composite film as claimed in claim 9.

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