Carbide metal coated carbon materials

Abstract

To provide a metal carbide-coating carbon material capable of suppressing gas generation in a high-temperature environment.SOLUTION: The present invention is a metal carbide-coating carbon material that comprises: a carbon base material which is mainly composed of carbon; and a metal carbide coating film that coats at least a part of the carbon base material, wherein: the metal carbide that constitutes the metal carbide-coating film is at least one metal carbide selected from the group consisting of tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide; the carbon base material comprises at least one element selected from the group consisting of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur; and a total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate is 10 mass ppm or more and 10,000 mass ppm or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a metal carbide-coated carbon material having a metal carbide coating film on the surface of a carbon substrate.

Background Art

[0002] Wide Band Gap semiconductors such as SiC and GaN have a high breakdown electric field strength and excellent heat resistance compared to Si semiconductors, and have low losses, so they are suitable for power semiconductors. On the other hand, Wide Band Gap semiconductors have a higher wafer manufacturing cost compared to Si semiconductors. Therefore, reduction of the manufacturing cost of Wide Band Gap semiconductor wafers is required. The costs involved in the crystal growth process and the epitaxial growth process of Wide Band Gap semiconductors have a great influence on the manufacturing cost of Wide Band Gap semiconductor wafers. In order to reduce the manufacturing cost of Wide Band Gap semiconductor wafers, improvement of the yields of those processes is required.

[0003] There are several factors that reduce the yields in the crystal growth process and the epitaxial growth process of Wide Band Gap semiconductors. One of them is the generation of gas from the carbon substrate used as a crucible, a guide member, or a susceptor. It is considered that gas is generated due to sublimation of the carbon substrate itself or desorption of hydrocarbon gases adsorbed on the carbon substrate, and the growth rate decreases because the crystal orientation changes during crystal growth due to this gas.

[0004] As a countermeasure, there is a method of coating a carbon substrate with a metal carbide film. Metal carbides such as tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide have high melting points and are excellent in chemical stability, strength, toughness, and corrosion resistance. Therefore, by coating a carbon substrate with a metal carbide, the heat resistance, chemical stability, strength, toughness, and corrosion resistance of the carbon substrate can be improved, and the generation of gas can be suppressed.

[0005] Furthermore, it is known that gas generation can be suppressed by treating the carbon substrate itself to a high purity. In fact, Patent Document 1 uses a carbon substrate that has been treated to a high purity, and Non-Patent Document 1 shows that the gas released from the carbon substrate when heated can be reduced by treating the carbon substrate to a high purity. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 5502721 [Non-patent literature]

[0007] [Non-Patent Document 1] Toyo Tanso Co., Ltd. Special Graphite Products Catalog, Internet: https: / / www.toyotanso.co.jp / Products / download / [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, when the carbon substrate described in Patent Document 1 and the carbon substrate described in Non-Patent Document 1 were coated with a metal carbide film and used in a wide-band gap semiconductor manufacturing apparatus, the suppression of gas generation during the crystal growth process and epitaxial growth process was insufficient.

[0009] Therefore, the present invention aims to provide a metal carbide-coated carbon material that can suppress gas generation in high-temperature environments. [Means for solving the problem]

[0010] As a result of diligent research, the inventors have discovered that by setting the total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbide substrate of the metal carbide coated carbon material to between 10 ppm by mass and 10,000 ppm by mass, gas generation from the metal carbide coated carbon material under high-temperature conditions can be suppressed, thus completing the present invention. The gist of the present invention is as follows. [1] A metal carbide coated carbon material comprising a carbon substrate mainly composed of carbon and a metal carbide coating film covering at least a portion of the carbon substrate, The metal carbide constituting the aforementioned metal carbide coating film is at least one metal carbide selected from the group consisting of tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide. The carbon substrate comprises at least one element selected from the group consisting of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur. A metal carbide coated carbon material wherein the total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate is 10 ppm by mass or more and 10,000 ppm by mass or less. [2] The metal carbide coated carbon material according to [1] above, wherein the concentration of iron in the carbon substrate is 1 ppm by mass or more and 10,000 ppm by mass or less. [3] The metal carbide coated carbon material according to [1] or [2] above, wherein the concentration of titanium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less. [4] The metal carbide coated carbon material according to any one of [1] to [3] above, wherein the concentration of magnesium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less. [5] The metal carbide coated carbon material according to any one of [1] to [4] above, wherein the silicon concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less. [6] The metal carbide coated carbon material according to any one of [1] to [5] above, wherein the calcium concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less. [7] The metal carbide coated carbon material according to any one of [1] to [6] above, wherein the vanadium concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less. [8] The metal carbide coated carbon material according to any one of [1] to [7] above, wherein the concentration of sodium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less. [9] The metal carbide coated carbon material according to any one of [1] to [8] above, wherein the concentration of potassium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

[10] The metal carbide coated carbon material according to any one of [1] to [9] above, wherein the sulfur concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

[11] The metal carbide coated carbon material according to any one of [1] to

[10] above, wherein the thickness of the metal carbide coating film is 10 μm or more and 100 μm or less.

[12] The metal carbide coated carbon material according to any one of [1] to

[11] above, wherein the arithmetic mean roughness Ra of the surface of the metal carbide coating film is 0.1 μm or more and 9.5 μm or less.

[13] The metal carbide coated carbon material according to any one of [1] to

[12] above, wherein the arithmetic mean roughness Ra of the surface of the carbon substrate is 0.1 μm or more and 10.0 μm or less.

[14] The metal carbide coated carbon material according to any one of [1] to

[13] above, wherein the metal carbide constituting the metal carbide coating film is tantalum carbide. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a metal carbide coated carbon material that can suppress gas generation in high-temperature environments. [Brief explanation of the drawing]

[0012] [Figure 1]It is a schematic diagram of an external heat type reduced pressure CVD apparatus according to this embodiment. [Figure 2] It is a schematic set diagram of a corrosion test method according to this embodiment. [Figure 3] It is a schematic diagram for explaining a method for measuring the adhesion strength of a metal carbide coating film according to this embodiment. [Figure 4] Results of corrosion tests of tantalum carbide-coated carbon materials of Examples 1 to 4 and Comparative Example 1.

Mode for Carrying Out the Invention

[0013] The metal carbide-coated carbon material of the present invention will be described by taking a tantalum carbide-coated carbon material as an example.

[0014] [Tantalum Carbide-Coated Carbon Material] The tantalum carbide-coated carbon material of one embodiment of the present invention includes a carbon base material mainly composed of carbon and a tantalum carbide coating film that coats at least a part of the carbon base material. The carbon base material contains at least one element selected from the group consisting of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur, and the total concentration of the concentration of aluminum, the concentration of iron, the concentration of magnesium, the concentration of titanium, the concentration of silicon, the concentration of calcium, the concentration of vanadium, the concentration of nickel, the concentration of sodium, the concentration of potassium, and the concentration of sulfur in the carbon base material is 10 mass ppm or more and 10,000 mass ppm or less.

[0015] (Carbon Base Material) The carbon base material in the tantalum carbide-coated carbon material of one embodiment of the present invention is a base material mainly composed of carbon. The carbon base material may further contain chlorine. Examples of the material of the carbon base material include isotropic graphite, extruded graphite, pyrolytic graphite, carbon fiber reinforced carbon composite material (C / C composite), etc. The shape and characteristics of the carbon base material are not particularly limited, and those processed into arbitrary shapes according to applications and the like can be used.

[0016] <Total Concentration of Elements> The carbon substrate in the tantalum carbide-coated carbon material of one embodiment of the present invention contains at least one element selected from the group consisting of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur. The total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate is between 10 ppm by mass and 10,000 ppm by mass. If the total concentration of the above elements is greater than 10,000 ppm by mass, the amount of gas generated from the carbon substrate in a high-temperature environment increases, and as a result, when the tantalum carbide-coated carbon material using this carbon substrate is used in a manufacturing apparatus for wide-band gap semiconductors, the yield of wide-band gap semiconductors may decrease. Furthermore, even if the total concentration of the above elements is less than 10 ppm by mass, the amount of gas generated from the carbon substrate in a high-temperature environment cannot be reduced as much as when the total concentration of the above elements is 10 ppm by mass. In other words, if the total concentration of the above elements is less than 10 ppm by mass, the resulting increase in the manufacturing cost of the carbon substrate may result in insufficient cost reduction in the manufacturing of wide-band gap semiconductor wafers. From this viewpoint, the total concentration of the above elements is preferably 15 ppm by mass or more and 5000 ppm by mass or less, and more preferably 20 ppm by mass or more and 1000 ppm by mass or less. The concentration of the above elements in the carbon substrate can be measured by the method described in the examples below. Furthermore, the total concentration of the above elements can be adjusted, for example, by heating the carbon substrate in a halogen gas at about 2000°C to volatilize the above elements in the carbon substrate as low-boiling-point halides. Specifically, a method of removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0017] <Iron concentration> In the tantalum carbide-coated carbon material of one embodiment of the present invention, the iron concentration in the carbon substrate is preferably 1 ppm by mass or more and 10,000 ppm by mass or less. When the iron concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the iron concentration is 1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the iron concentration can be suppressed. From this viewpoint, the iron concentration is more preferably 1 ppm by mass or more and 4,000 ppm by mass or less, even more preferably 1 ppm by mass or more and 1,000 ppm by mass or less, even more preferably 1 ppm by mass or more and 100 ppm by mass or less, and even more preferably 1 ppm by mass or more and 50 ppm by mass or less. The iron concentration in the carbon substrate can be measured by the method described in the examples below. The iron concentration can also be adjusted, for example, by heating the carbon substrate in a halogen gas at about 2,000°C to volatilize the iron in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities using chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0018] <Titanium concentration> In the tantalum carbide-coated carbon material of one embodiment of the present invention, the titanium concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the titanium concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the titanium concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the titanium concentration can be suppressed. From this viewpoint, the titanium concentration is more preferably 0.1 ppm by mass or more and 2000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 1000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 500 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 10 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 3 ppm by mass or less. The titanium concentration in the carbon substrate can be measured by the method described in the examples below. The titanium concentration can also be adjusted, for example, by heating the carbon substrate in a halogen gas at about 2000°C to volatilize the titanium in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities using chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0019] <Magnesium Flavor> In the tantalum carbide coated carbon material of one embodiment of the present invention, the magnesium concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the magnesium concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the magnesium concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the magnesium concentration can be suppressed. From this viewpoint, the magnesium concentration is more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 20 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 10 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 2 ppm by mass or less. The magnesium concentration in the carbon substrate can be measured by the method described in the examples below. Furthermore, the magnesium concentration can be adjusted, for example, by heating the carbon substrate in a halogen gas at approximately 2000°C to volatilize the magnesium in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0020] <Silicon concentration> In the tantalum carbide coated carbon material of one embodiment of the present invention, the silicon concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the silicon concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the silicon concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the silicon concentration can be suppressed. From this viewpoint, the silicon concentration is more preferably 0.1 ppm by mass or more and 1,000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 500 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 200 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 30 ppm by mass or less. The silicon concentration in the carbon substrate can be measured by the method described in the examples below. Furthermore, the silicon concentration can be adjusted, for example, by heating a carbon substrate in a halogen gas at approximately 2000°C to volatilize the silicon in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0021] <Calcium Flavor> In the tantalum carbide coated carbon material of one embodiment of the present invention, the calcium concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the calcium concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the calcium concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the calcium concentration can be suppressed. From this viewpoint, the calcium concentration is more preferably 0.1 ppm by mass or more and 2,000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 1,000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 10 ppm by mass or less. The calcium concentration in the carbon substrate can be measured by the method described in the examples below. Furthermore, the calcium concentration can be adjusted, for example, by heating the carbon substrate in a halogen gas at approximately 2000°C to volatilize the calcium in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0022] <Vanadium concentration> In the tantalum carbide coated carbon material of one embodiment of the present invention, the vanadium concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the vanadium concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the vanadium concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the vanadium concentration can be suppressed. From this viewpoint, the vanadium concentration is more preferably 0.1 ppm by mass or more and 1,000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 500 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 10 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less. The vanadium concentration in the carbon substrate can be measured by the method described in the examples below. Furthermore, the vanadium concentration can be adjusted, for example, by heating a carbon substrate in a halogen gas at approximately 2000°C to volatilize the vanadium in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0023] <Sodium concentration> In the tantalum carbide-coated carbon material of one embodiment of the present invention, the sodium concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the sodium concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the sodium concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that occurs in order to reduce the sodium concentration can be suppressed. From this viewpoint, the sodium concentration is more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 20 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less. The sodium concentration in the carbon substrate can be measured by the method described in the examples below. The sodium concentration can also be adjusted, for example, by heating the carbon substrate in a halogen gas at about 2000°C to volatilize the sodium in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities using chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0024] <Potassium concentration> In the tantalum carbide-coated carbon material of one embodiment of the present invention, the potassium concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the potassium concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the potassium concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the potassium concentration can be suppressed. From this viewpoint, the potassium concentration is more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 20 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 10 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 2 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 1 ppm by mass or less. The potassium concentration in the carbon substrate can be measured by the method described in the examples below. Furthermore, the potassium concentration can be adjusted, for example, by heating the carbon substrate in a halogen gas at approximately 2000°C to volatilize the potassium in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0025] <Sulfur concentration> In the tantalum carbide coated carbon material of one embodiment of the present invention, the sulfur concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the sulfur concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the sulfur concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the sulfur concentration can be suppressed. From this viewpoint, the sulfur concentration is more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 20 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 10 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 2 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 1 ppm by mass or less. The sulfur concentration in the carbon substrate can be measured by the method described in the examples below. Furthermore, the sulfur concentration can be adjusted, for example, by hydrogenating the carbon substrate and volatilizing the sulfur in the carbon substrate as hydrogen sulfide.

[0026] <Aluminum concentration> In the tantalum carbide coated carbon material of one embodiment of the present invention, the concentration of aluminum in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the aluminum concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the aluminum concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the aluminum concentration can be suppressed. From this viewpoint, the aluminum concentration is more preferably 0.1 ppm by mass or more and 1,000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 20 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less. The concentration of aluminum in the carbon substrate can be measured by the method described in the examples below. Furthermore, the aluminum concentration can be adjusted, for example, by heating the carbon substrate in a halogen gas at approximately 2000°C to volatilize the aluminum in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0027] <Nickel concentration> In the tantalum carbide coated carbon material of one embodiment of the present invention, the nickel concentration in the carbon substrate is preferably 0.1 ppm by mass or more and 10,000 ppm by mass or less. When the nickel concentration is 10,000 ppm by mass or less, the generation of gas from the carbon substrate in a high-temperature environment can be further suppressed. Also, when the nickel concentration is 0.1 ppm by mass or more, the increase in the cost of the carbon substrate that would occur to reduce the nickel concentration can be suppressed. From this viewpoint, the nickel concentration is more preferably 0.1 ppm by mass or more and 1,000 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 100 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 50 ppm by mass or less, even more preferably 0.1 ppm by mass or more and 20 ppm by mass or less, and even more preferably 0.1 ppm by mass or more and 5 ppm by mass or less. The nickel concentration in the carbon substrate can be measured by the method described in the examples below. Furthermore, the nickel concentration can be adjusted, for example, by heating a carbon substrate in a halogen gas at approximately 2000°C to volatilize the nickel in the carbon substrate as a low-boiling-point halide. Specifically, a method for removing impurities with chlorine is described in Reference 1 (Kazuhiro Nagata, Iron and Steel, Vol. 73, No. 9, pp. 1077-1081 (1987)).

[0028] <Arithmetic surface roughness Ra> The arithmetic mean roughness Ra of the carbon substrate surface affects semiconductor single crystal growth and epitaxial growth. A higher arithmetic mean roughness Ra of the carbon substrate surface tends to result in greater peel strength between the carbon substrate and the tantalum carbide coating film, which is preferable. On the other hand, if the arithmetic mean roughness Ra of the carbon substrate surface is too high, the specific surface area increases, which can cause cracks and delamination, potentially shortening the product life when used as a component for semiconductor single crystal growth and epitaxial growth. Therefore, from the viewpoint of product life of tantalum carbide coated carbon materials, the arithmetic mean roughness Ra of the carbon substrate surface is preferably 10.0 μm or less. Considering the occurrence rate of cracks and delamination between the carbon substrate and the tantalum carbide coating film, the arithmetic mean roughness Ra of the carbon substrate surface is preferably 0.1 μm to 10.0 μm, and more preferably 2.0 μm to 6.0 μm. This method increases the peel strength between the carbon substrate and the tantalum carbide coating, thereby extending the product life when used as a component for semiconductor single crystal growth and epitaxial growth. The arithmetic mean roughness Ra of the carbon substrate surface was measured according to JIS B 0633:2001 (ISO 4288:1996).

[0029] <Linear thermal expansion coefficient> The linear thermal expansion coefficient of the carbon substrate is preferably 3.5 × 10⁻⁶. -6 / ℃ or higher 8.2×10 -6 The temperature is below / °C. The linear thermal expansion coefficient of the carbon substrate is 3.5 × 10⁻⁶. -6 / ℃ or higher 8.2×10 -6 If the temperature is below / ℃, the occurrence of microcracks in the tantalum carbide coating can be further suppressed. From this viewpoint, the linear thermal expansion coefficient of the carbon substrate is more preferably 0.5.0 × 10⁻⁶. -6 ~7.5×10 -6 The temperature is / °C. The linear thermal expansion coefficient of the tantalum carbide coating is approximately 6.3 × 10⁻⁶. -6 The temperature is / °C. The linear thermal expansion coefficient of the carbon substrate can be measured in accordance with JIS R 1618.

[0030] (Tantalum carbide coating) The tantalum carbide coating film is a film whose main component is tantalum carbide. The tantalum carbide coating film may coat a portion of the carbon substrate or the entire carbon substrate. Furthermore, the tantalum carbide coating film may contain trace amounts of atoms other than carbon and tantalum, as long as they do not impair the effects of the present invention. For example, the tantalum carbide coating film may contain impurity elements or doping elements other than carbon and tantalum at a concentration of 10,000 ppm by mass or less.

[0031] <film thickness> If the tantalum carbide coating is too thin, gases generated from the carbon substrate may pass through the coating and adversely affect the semiconductor single crystal. On the other hand, if the tantalum carbide coating is too thick, the deposition time will be extended, increasing the deposition cost. Considering these factors together, the thickness of the metal carbide coating is preferably between 10 μm and 100 μm, and more preferably between 20 μm and 50 μm. The thickness of the tantalum carbide coating was measured based on cross-sectional observation of the tantalum carbide coating using a scanning electron microscope (SEM). Specifically, the thickness of five cross-sections of the tantalum carbide coating was measured from images of the cross-section of the tantalum carbide coating taken with a scanning electron microscope (SEM), and the average value was taken as the thickness of the tantalum carbide coating.

[0032] <Arithmetic surface roughness Ra> The arithmetic mean roughness Ra of the tantalum carbide coating surface is preferably 0.1 μm to 9.5 μm, and more preferably 2.0 μm to 5.5 μm. If the arithmetic mean roughness Ra of the tantalum carbide coating surface is large, it can cause cracks and delamination, similar to the carbon substrate, and may shorten the product life when used as a component for semiconductor single crystal growth and epitaxial growth. The arithmetic mean roughness Ra of the tantalum carbide coating surface immediately after deposition varies depending on the arithmetic mean roughness Ra of the carbon substrate surface, and tends to be slightly smaller than the arithmetic mean roughness Ra of the carbon substrate surface. The arithmetic mean roughness Ra of the tantalum carbide coating surface can also be controlled by polishing, but since this increases the manufacturing process, it is preferable to select the arithmetic mean roughness Ra of the carbon substrate surface according to the desired arithmetic mean roughness Ra of the tantalum carbide coating surface. Note that the arithmetic mean roughness Ra used here is a value measured according to JIS B0633:2001 (ISO 4288:1996).

[0033] <Method for manufacturing tantalum carbide-coated carbon material> A tantalum carbide-coated carbon material according to one embodiment of the present invention can be manufactured by forming a tantalum carbide layer on the surface of a carbon substrate. The tantalum carbide coating can be formed on the surface of the carbon substrate by methods such as chemical vapor deposition (CVD), sintering, or carbonization. Among these, the CVD method is preferred as a method for forming a tantalum carbide coating because it can form a uniform and dense tantalum carbide coating.

[0034] Furthermore, CVD methods include thermal CVD, photoCVD, and plasma CVD, and for example, thermal CVD can be used to form the tantalum carbide layer. Thermal CVD has advantages such as a relatively simple apparatus configuration and no plasma damage to the carbon substrate. For forming a tantalum carbide coating film by thermal CVD, for example, an externally heated vacuum CVD apparatus 10 as shown in Figure 1 can be used. In the externally heated vacuum CVD apparatus 10, the carbon substrate 14 is supported by support means 15 in a reaction chamber 12 equipped with a heater 13, a raw material supply unit 16, an exhaust unit 17, etc.

[0035] A method for producing a tantalum carbide-coated carbon material according to one embodiment of the present invention will be described with reference to Figure 1. First, the carbon substrate 14 is placed inside the reaction chamber 12 of the externally heated reduced-pressure CVD apparatus 10. The carbon substrate 14 is supported by a support means 15 having three support parts with pointed tips.

[0036] Next, the reaction chamber 12 is heated. For example, the reaction chamber 12 is heated under conditions of 10 to 1000 Pa of atmospheric pressure and 800 to 2200°C of temperature.

[0037] Next, a tantalum carbide coating film is formed on the surface of the carbon substrate 14. As raw material gases, a gas of a carbon-carbon compound such as methane (CH4), hydrogen (H2) gas, and a tantalum halogen gas such as tantalum pentachloride (TaCl5) are supplied from the raw material supply unit 16 to the reaction chamber 12. The tantalum halogen gas can be generated, for example, by heating and vaporizing tantalum halogen, or by reacting tantalum metal with a halogen gas. Subsequently, the raw material gas supplied from the raw material supply unit 16 is subjected to a thermal CVD reaction at a high temperature of 800 to 2200°C and a pressure of 1 to 1000 Pa to form a tantalum carbide coating film on the carbon substrate 14.

[0038] The tantalum carbide-coated carbon material of one embodiment described above is an example of the metal carbide-coated carbon material of the present invention, and the metal carbide-coated carbon material of the present invention is not limited to the tantalum carbide-coated carbon material of one embodiment. In the metal carbide-coated carbon material of the present invention, the metal carbide constituting the metal carbide coating film that coats the carbon substrate is not limited to tantalum carbide. For example, carbides such as niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide can be used as the metal carbide constituting the metal carbide coating film that coats the carbon substrate. Alternatively, a combination of two or more metal carbides selected from the group consisting of tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide may be used as the metal carbide constituting the metal carbide coating film that coats the carbon substrate. Among tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide, tantalum carbide is preferred because it has the highest melting point and excellent chemical stability, strength, and corrosion resistance. [Examples]

[0039] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples.

[0040] The metal carbide-coated carbon materials of Examples 1-14 and Comparative Examples 1-4 were prepared as follows. (Example 1) First, isotropic graphite doped with aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur was prepared. This isotropic graphite was processed into cylindrical shapes with an outer diameter of 40 mm, an inner diameter of 30 mm, and a height of 30 mm, and these were used as carbon substrates 14. The arithmetic mean surface roughness Ra of these carbon substrates was 6.0 μm, and the linear thermal expansion coefficient of carbon substrate 14 was 7.0 × 10⁻⁶. -6 The temperature was / °C. For the linear thermal expansion coefficient of the carbon substrate, a thermomechanical analyzer (TMA7300) manufactured by Hitachi High-Tech Corporation was used, and values ​​for thermal expansion coefficients in the temperature range from 200°C to 1200°C were employed.

[0041] Next, as shown in Figure 1, the carbon substrate 14 was placed inside the reaction chamber 12 of the externally heated reduced-pressure CVD apparatus 10. The carbon substrate 14 was supported by a support means 15 having three support parts with pointed tips. At this time, the tips of the support parts were in contact with the outer surface of the frustoconical carbon substrate 14, the outer surface of the bottomed cylindrical carbon substrate 14, the lower surface of the disc-shaped carbon substrate 14, and the outer surface of the cylindrical carbon substrate 14.

[0042] Next, methane (CH4) gas was supplied from the raw material supply unit 16 at a flow rate of 0.25 SLM, argon (Ar) gas at a flow rate of 1.0 SLM, hydrogen (H2) gas at a flow rate of 0.125 SLM, and tantalum pentachloride (TaCl5), which had been heated to 220°C and vaporized, was supplied at a flow rate of 0.25 SLM. The reaction was carried out under conditions of a pressure of 100 Pa and a temperature of 1250°C inside the reaction chamber 12 to form a tantalum carbide coating film on the entire surface of the carbon substrate 14.

[0043] From the reaction chamber 12, the carbon substrate 14 coated with a tantalum carbide film was removed, and a cylinder made of tantalum carbide-coated carbon material was completed.

[0044] (Examples 2-5) Isotropic graphite samples with varying doping amounts of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur were prepared. Cylinders were fabricated and evaluated using the same method as in Example 1.

[0045] (Example 6) A cylinder was fabricated in the same manner as in Example 1, except that the flow rate of hydrogen (H2) gas was changed to 0.15 SLM, the flow rate of tantalum pentachloride (TaCl5) was changed to 0.3 SLM, and the film deposition time was shortened to achieve a film thickness of 10 μm. The cylinder was then evaluated.

[0046] (Example 7) A cylinder was fabricated and evaluated using the same method as in Example 1, except that the hydrogen (H2) gas flow rate was changed to 0.15 SLM and the film deposition time was extended to achieve a film thickness of 50 μm.

[0047] (Example 8) A cylinder was prepared and evaluated in the same manner as in Example 1, except that the surface of the carbon substrate 14 was polished to achieve an arithmetic mean roughness Ra of 0.1 μm.

[0048] (Example 9) A cylinder was fabricated in the same manner as in Example 1, except that the surface of the carbon substrate 14 was sandblasted by projecting an abrasive onto it to achieve an arithmetic mean roughness Ra of 10 μm, and the cylinder was then evaluated.

[0049] (Example 10) A cylinder was fabricated and evaluated in the same manner as in Example 1, except that the metal chloride was changed from tantalum pentachloride (TaCl5) to niobium pentachloride (NbCl5) and supplied at a flow rate of 0.25 SLM.

[0050] (Example 11) A cylinder was fabricated and evaluated in the same manner as in Example 1, except that the metal chloride was changed from tantalum pentachloride (TaCl5) to hafnium tetrachloride (HfCl4) and supplied at a flow rate of 0.25 SLM.

[0051] (Example 12) A cylinder was fabricated and evaluated in the same manner as in Example 1, except that the metal chloride was changed from tantalum pentachloride (TaCl5) to zirconium tetrachloride (ZrCl4) and supplied at a flow rate of 0.25 SLM.

[0052] (Example 13) A cylinder was fabricated and evaluated in the same manner as in Example 1, except that the metal chloride was changed from tantalum pentachloride (TaCl5) to tungsten pentachloride (WCl5) and supplied at a flow rate of 0.25 SLM.

[0053] (Example 14) A cylinder was prepared and evaluated in the same manner as in Example 1, except that a mixture of tantalum pentachloride (TaCl5) and niobium pentachloride (NbCl5) (TaCl5:NbCl5=100:1) was supplied as the metal chloride at a flow rate of 0.25 SLM.

[0054] (Comparative Example 1) Isotropic graphite with different doping amounts of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur was prepared. Cylinders were fabricated in the same manner as in Example 1, except that the flow rate of hydrogen (H2) gas was changed to 0 SLM and the flow rate of tantalum pentachloride (TaCl5) was changed to 0.5 SLM, and the cylinders were evaluated.

[0055] (Comparative Example 2) Isotropic graphite with different doping amounts of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur was prepared, and cylinders were fabricated in the same manner as in Example 1, except that the film deposition time was shortened and the thickness of the tantalum carbide coating film was changed to 2 μm. The cylinders were then evaluated.

[0056] (Comparative Example 3) Isotropic graphite with different doping amounts of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur was prepared, and cylinders were fabricated in the same manner as in Example 1, except that the arithmetic mean roughness Ra of the carbon substrate 14 surface was set to 32 μm. The cylinders were then evaluated. The results are shown in Table 1.

[0057] (Comparative Example 4) Isotropic graphite with different doping amounts of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur was prepared, and cylinders were fabricated in the same manner as in Example 1, except that the arithmetic mean roughness Ra of the carbon substrate 14 surface was set to 0.05 μm. The cylinders were then evaluated. The results are shown in Table 1.

[0058] The following evaluations were performed on the cylinders of Examples 1 to 14 and the cylinders of Comparative Examples 1 to 4. [Thickness of metal carbide coating] The thickness of the metal carbide coating was measured by cross-sectional observation of the coating using a scanning electron microscope (SEM).

[0059] [Arithmetic mean surface roughness Ra] The arithmetic mean roughness Ra of the carbon substrate surface and the surface of the metal carbide coating film formed on the carbon substrate surface was measured using a Mitutoyo SurfTest SJ-210.

[0060] [Elemental concentrations in carbon substrates] <Measurement of sulfur concentration> The sulfur concentration in the carbon substrate was measured using a trace sulfur analyzer (manufactured by Nitto Seikou Analytech Co., Ltd., product name "TS-100"). (1) Method of preparing the sample After film formation, the metal carbide-coated carbon material was cut out, and the metal carbide coating was removed to leave only the carbon substrate. This was then wrapped in a Teflon® sheet and roughly crushed with a hammer. The coarse powder was then finely ground in a B4C mortar and pestle to prepare the sample for measurement. (2) Measurement of sulfur concentration A 10 mg sample was burned at 1000°C in an oxygen atmosphere, and the resulting SOx was analyzed to calculate the sulfur concentration in the carbon substrate.

[0061] <Concentration of elements other than sulfur> The tantalum carbide coating was peeled off from the metal carbide coated carbon material, and the metal concentration of the underlying carbon substrate was measured using an ICP-MS analyzer (inductively coupled plasma mass spectrometer) (900°C pyrolysis / gas analysis) (manufactured by Agilent Technologies, Inc., product name "Agilent 7900") to determine the concentration of elements other than sulfur in the carbon substrate. (1) Method for preparing the sample for measurement A carbon material coated with metal carbide was cut out, and the metal carbide coating was removed to leave only the carbon substrate. This was then wrapped in a Teflon® sheet and roughly crushed with a hammer, and the coarse powder was finely ground in a B4C mortar. Slightly more than 0.1g of this fine powder was weighed into a microwave decomposition container and decomposed according to the following decomposition recipe. The mixture was air-cooled until the temperature dropped to 40°C between steps. (Disassembly recipe) STEP.1: HNO3:5 mL + H2SO4:2.5 mL (80℃*2min, 60℃*3min, 220℃*20min, 230℃*30min) STEP.2:Add HClO4:0.5 mL (240℃*25min, 240℃*25min) The obtained solution was transferred to a 30 mL crucible and heated to dryness at 380°C. After drying, the metal residue was dissolved with a small amount of nitric acid, cooled, and then diluted to 10 mL with a small amount of hydrofluoric acid and pure water to prepare the measurement solution. (2) Measurement of concentration Using an ICP-MS analyzer, the elemental concentrations in the carbon substrate were measured from the obtained measurement solution under the following conditions. (Measurement conditions) Alkali and alkaline earth metals: Cool Plasma (RF power: 600W) Other elements: Hot Plasma (RF power: 1500W)

[0062] [Method for measuring the amount of corrosion of carbon substrates] Figure 2 shows a cross-sectional view of the corrosion resistance test apparatus. A cylindrical metal carbide-coated carbon material 21 with an outer diameter of 40 mm, an inner diameter of 30 mm, and a height of 30 mm was prepared. This was covered with an insulating material 22 and set inside a quartz tube 23. The temperature was raised to 2300°C by high-frequency induction heating, held for 2 hours after reaching the temperature, and then cooled down over the next 2 hours. The temperature of the heating element was measured using a radiation thermometer. Nitrogen was introduced at a flow rate of 1.0 SLM immediately after heating began and continued until cooling started. The weight of the metal carbide-coated carbon material was measured before and after heating. The weight change (mg) of the metal carbide-coated carbon material was calculated as (weight after heating - weight before heating) × 100.

[0063] Furthermore, the temperature range of the thermal desorption gas analysis (TDS) method is limited to 1500°C, making it impossible to investigate gas generation in the high-temperature environments of 1600-2300°C during the crystal growth and epitaxial growth processes of wide-band gap semiconductors. Therefore, gas generation in high-temperature environments was indirectly measured by measuring the weight change of the carbon substrate. In other words, a larger weight change of the carbon substrate corresponds to a larger amount of gas generated in high-temperature environments. Previous research has shown that when carbon substrates are heated to around 2200°C, they react with nitrogen to produce gases such as cyanide and dicyanide, resulting in corrosion of the carbon substrate. Reference 2 (GJ TENNENHOUSE, JA MANGELS, JOURNAL OF MATERIALS SCIENCE LETTERS, 1, 1982, 282-284) also states that dicyanide is produced by the reaction of N2 with carbon. Furthermore, looking at Non-Patent Document 1 mentioned above, the TDS results show that saturation is reached at 1500°C, and it is thought that the gases emitted by hydrocarbons adsorbed on the carbon substrate itself do not have much effect in the high-temperature environment of 1600-2300°C. Therefore, it is considered that the weight change at 2300°C is due to the reaction between N2 and carbon. It is also thought that the metal contained in the substrate is involved as a catalyst in this reaction, which causes the difference in the amount of weight change.

[0064] [Method for measuring the adhesion strength of metal carbide coatings] The adhesion strength of the metal carbide coating was measured using a thin-film adhesion strength measuring instrument (Romulus, manufactured by Quad Group). As shown in Figure 3, the metal carbide coating 41 and pin 46 were bonded together with adhesive 45, and the pin 46 was pulled while being pressed down with a pressing jig 44. The stress at which the metal carbide coating 41 peeled off was measured. Five measurements were taken, and the average value of the five measurements was taken as the adhesion strength of the metal carbide coating.

[0065] Table 1 shows the manufacturing conditions for Examples 1-14 and Comparative Examples 1-4. [Table 1]

[0066] The evaluation results for Examples 1-4 and Comparative Example 1 are shown in Figure 4, and the evaluation results for Examples 1-14 and Comparative Examples 1-4 are shown in Table 2. [Table 2]

[0067] Comparing the results from Examples 1 to 14 and Comparative Examples 1 to 4, it was found that when the total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate was between 10 ppm by mass and 10,000 ppm by mass, the weight change of the metal carbide-coated carbon material was suppressed.

[0068] Figure 4 shows the results of Examples 1 through 4 and Comparative Example 1, plotting the weight change per corrosion resistance test (2 hours) and the number of uses. Comparing these, when the total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate is between 10 ppm by mass and 10,000 ppm by mass, the weight loss per test hardly changes as the number of tests increases. On the other hand, in the case of a composition like that of Comparative Example 1, it was shown that the weight loss increases with increasing number of tests.

[0069] Comparing the results of Examples 1, 6, and 7 with those of Comparative Example 2, it was found that when the total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate was between 10 ppm by mass and 10,000 ppm by mass, and the thickness of the tantalum carbide coating film was between 10 μm and 100 μm, the weight change of the metal carbide coated carbon material was further suppressed. When the thickness of the tantalum carbide coating film was less than 10 μm, the weight loss was larger. Furthermore, when the thickness of the tantalum carbide coating film exceeded 100 μm, the film formation time increased, which is undesirable because it increased the film formation cost. Therefore, it is preferable that the thickness of the tantalum carbide coating film be in the range of 10 μm to 100 μm.

[0070] Comparing the results of Examples 1, 8, and 9 with those of Comparative Examples 3 and 4, it was found that when the total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate was between 10 ppm by mass and 10,000 ppm by mass, and the arithmetic mean roughness Ra of the surface of the metal carbide coating film was between 0.1 μm and 9.5 μm, or the arithmetic mean roughness Ra of the surface of the carbon substrate was between 0.1 μm and 10.0 μm, the weight change of the metal carbide coated carbon material was further suppressed. When the arithmetic mean roughness Ra of the surface of the carbon substrate was greater than 10 μm, the weight loss was greater. When the arithmetic mean roughness Ra of the surface of the carbon substrate was less than 0.1 μm, the weight loss was also greater.

[0071] Comparing the results of Example 1 and Examples 10-14, it was found that when the metal carbide coating was a tantalum carbide coating, the weight change of the metal carbide-coated carbon material was further suppressed. [Explanation of symbols]

[0072] 10. External Heating Type Reduced Pressure CVD Apparatus 11 Top Chamber 12 Reaction Chambers 13 Heater 14 Carbon substrate 15 Support means 16 Raw material supply department 17 Exhaust section 20 Schematic diagram of the corrosion resistance testing apparatus set 21 Metal carbide coated carbon material 22 Insulation 23 Quartz tube 24 coils 41 Metal carbide coating film 42 Carbon-based substrate 44. Holding jig 45 Adhesives 46 pins

Claims

1. A metal carbide coated carbon material comprising a carbon substrate mainly composed of carbon and a metal carbide coating film covering at least a portion of the carbon substrate, The metal carbide constituting the aforementioned metal carbide coating film is at least one metal carbide selected from the group consisting of tantalum carbide, niobium carbide, zirconium carbide, hafnium carbide, and tungsten carbide. The carbon substrate comprises at least one element selected from the group consisting of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur. A metal carbide coated carbon material wherein the total concentration of aluminum, iron, magnesium, titanium, silicon, calcium, vanadium, nickel, sodium, potassium, and sulfur in the carbon substrate is 10 ppm by mass or more and 10,000 ppm by mass or less.

2. The metal carbide coated carbon material according to claim 1, wherein the concentration of iron in the carbon substrate is 1 ppm by mass or more and 10,000 ppm by mass or less.

3. The metal carbide coated carbon material according to claim 1, wherein the concentration of titanium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

4. The metal carbide coated carbon material according to claim 1, wherein the concentration of magnesium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

5. The metal carbide coated carbon material according to claim 1, wherein the silicon concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

6. The metal carbide coated carbon material according to claim 1, wherein the calcium concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

7. The metal carbide coated carbon material according to claim 1, wherein the vanadium concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

8. The metal carbide coated carbon material according to claim 1, wherein the concentration of sodium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

9. The metal carbide coated carbon material according to claim 1, wherein the concentration of potassium in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

10. The metal carbide coated carbon material according to claim 1, wherein the sulfur concentration in the carbon substrate is 0.1 ppm by mass or more and 10,000 ppm by mass or less.

11. The metal carbide coated carbon material according to claim 1, wherein the thickness of the metal carbide coating film is 10 μm or more and 100 μm or less.

12. The metal carbide coated carbon material according to claim 1, wherein the arithmetic mean roughness Ra of the surface of the metal carbide coating film is 0.1 μm or more and 9.5 μm or less.

13. The metal carbide coated carbon material according to claim 1, wherein the arithmetic mean roughness Ra of the surface of the carbon substrate is 0.1 μm or more and 10.0 μm or less.

14. The metal carbide coated carbon material according to claim 1, wherein the metal carbide constituting the metal carbide coating film is tantalum carbide.

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