KR102092280B1 - Silicon carbide powder - Google Patents

Abstract

It relates to a silicon carbide powder.
The silicon carbide powder has an impurity content of 1 ppm or less, and a weight ratio of carbon in the silicon carbide lattice is 30% or less.

Description

Silicon carbide powder {SILICON CARBIDE POWDER}

The present invention relates to a silicon carbide powder, and more particularly, to a silicon-rich silicon carbide powder.

Silicon carbide (SiC) is physically and chemically stable, has good heat resistance and thermal conductivity, and has excellent high temperature stability, high temperature strength, and wear resistance. Accordingly, silicon carbide is widely used as a material for industrial structures, and recently, it is also applied to semiconductor devices.

The silicon carbide powder is manufactured by synthesizing a silicon source and a carbon source, and can be produced by an Acheson method, a carbon heat reduction method, or a chemical vapor deposition (CVD) method. The thus prepared silicon carbide powder can be used for single crystal growth for making semiconductor devices.

When growing a single crystal, the molar ratio (C / Si ratio) of carbon and silicon constituting the silicon carbide powder acts as an important factor in forming a desired polytype. In particular, silicon-rich silicon carbide powder having a high silicon ratio is advantageous for growing 6H-silicon carbide single crystals.

In addition, when a single crystal is grown using silicon-rich silicon carbide powder, high-quality single crystal growth is possible by suppressing defects caused by carbon and forming stable stoichiometry.

The technical problem to be achieved by the present invention is to provide a silicon-rich silicon carbide powder.

The silicon carbide powder according to an embodiment of the present invention has an impurity content of 1 ppm or less, and a weight ratio of carbon in the silicon carbide lattice is 30% or less.

According to an embodiment of the present invention, it is possible to manufacture a silicon-rich silicon carbide powder having an increased silicon ratio.

1 is a flowchart illustrating a method of manufacturing silicon carbide powder according to an embodiment of the present invention.

The present invention can be applied to various changes and can have various embodiments, and specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as second and first may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the second component may be referred to as a first component without departing from the scope of the present invention, and similarly, the first component may also be referred to as a second component. The term and / or includes a combination of a plurality of related described items or any one of a plurality of related described items.

Terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "include" or "have" are intended to indicate the presence of features, numbers, steps, actions, components, parts or combinations thereof described herein, one or more other features. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, but the same or corresponding components are assigned the same reference numbers regardless of reference numerals, and overlapping descriptions thereof will be omitted.

1 is a flowchart illustrating a method of manufacturing silicon carbide powder according to an embodiment of the present invention.

Referring to FIG. 1, first, a mixing process of mixing a silicon source (Si source) and a carbon source (C source) is performed (S100).

In the step S100, the molar ratio of silicon contained in the silicon source and carbon contained in the carbon source when mixing may be 1: 1.5 to 1: 3.0.

Silicon source means a material providing silicon. The silicon source may be, for example, one or more selected from the group consisting of fumed silica, silica sol, silica gel, fine silica, quartz powder, and mixtures thereof.

Carbon source means a carbon-provided material. The carbon source may be a liquid carbon source, a solid carbon source, or an organic carbon compound. As a liquid carbon source, for example, phenol resin, pitch, or the like can be used. As the solid carbon source, for example, one or more selected from the group consisting of graphite, carbon black, carbon nano tube (CNT), fullerene, and mixtures thereof may be used. Organic carbon compounds used as a carbon source include phenol resin, franc resin, xylene resin, polyimide, polyurethane, polyvinyl alcohol, and polyacrylic. Nitrile (polyacrylonitrile), polyvinyl acetate (polyvinyl acetate), polyvinyl acetate, cellulose (cellulose), sugar, pitch (pitch), tar (tar) and may be one or more selected from the group consisting of mixtures thereof.

The silicon source and the carbon source can be mixed by a wet mixing process using a solvent or a dry mixing process without using a solvent. For example, it may be mixed using a super mixer (Sumper Mixer), a ball mill (ball mill), an attrition mill (attrition mill), a three roll mill (3roll mill), and the like.

Next, the powder mixed through the step S100 is recovered, and the mixed powder is heat-treated at a high temperature to synthesize fine grain silicon carbide powder (S110). Here, the synthesized particulate silicon carbide powder may be an α-phase silicon carbide powder.

In the step S110, the process of heat treatment of the mixed powder may be divided into a carbonization process and a synthesis process.

The carbonization process is not limited thereto, but may be performed for a predetermined time (for example, 1 hour or more) at a temperature condition of, for example, 600 ° C to 1200 ° C.

The synthesis process is not limited thereto, but may be performed for a predetermined time (for example, 1 hour to 3 hours) at a temperature condition of 1300 ° C to 1900 ° C.

In addition, the synthesis process may be performed while injecting a silicon-based gas together with an inert gas argon (Ar). Here, the silicon-based gas is SiH ₄ And gas containing silicon.

As such, the silicon gas injected during the synthesis process increases the proportion of silicon in the powder, thereby making it possible to synthesize fine silicon-rich silicon carbide powder.

Next, by recovering the particulate silicon carbide powder synthesized through the step S110 and grain growth, to prepare a coarse grain silicon carbide powder (S120).

In the step S120, the grain growth process is not limited thereto, but may be performed at a predetermined time (eg, 1 hour to 4 hours) at 1800 ° C to 2300 ° C.

In addition, the grain growth process may be performed while injecting a silicon-based gas together with argon (Ar), which is an inert gas. Here, the silicon-based gas is SiH ₄ And gas containing silicon.

As such, the silicon gas injected during the grain growth process increases the proportion of silicon in the powder to make it possible to synthesize granulated silicon-rich silicon carbide powder.

The silicon carbide powder of the granules manufactured according to an embodiment of the present invention may have a ratio of carbon weight in the silicon carbide lattice of 30 wt (wt)% or less. Further, the impurity content in the powder may be 1 ppm or less, and the content of residual silicon in the powder may be 200 ppm or less. In addition, the particle size (D ₅₀ ) may be 0.5 μm to 10.0 μm, or 100 μm to 500 μm. In addition, the dispersion (D ₉₀ / D ₁₀ ) may be 2 to 5.

Hereinafter, embodiments of the present invention will be described in more detail through experimental examples. Experimental examples are only presented to explain the embodiments of the present invention more clearly, and the embodiments of the present invention are not limited to the experimental examples.

Table 1 below compares the properties of silicon carbide powders prepared by a general manufacturing method and silicon carbide powders produced by a manufacturing method according to an embodiment of the present invention.

Table 1. Property comparison results

Comparison example

In order to prepare the silicon carbide powder of the comparative example, the dry silica and the phenol resin were respectively mixed as a silicon source and a carbon source, and after carbonizing the mixed powder at a temperature condition of 850 ° C, the temperature condition of 1700 ° C was maintained for 3 hours. A particulate silicon carbide powder is synthesized. In addition, by using this, a grain growth process is maintained for 5 hours at a temperature of 2100 ° C to prepare a silicon carbide powder of granulation.

The granulated silicon carbide powder thus prepared has a purity (impurity content in the powder) of 0.58 ppm and a residual silicon content in the powder of 80 ppm, as shown in Table 1 above. In addition, the particle size (D ₅₀ ) of the powder is 259 μm, and the dispersion (D ₉₀ / D ₁₀ ) is 2.52. In addition, the carbon weight in the silicon carbide lattice is 30.5%, exceeding 30%. Here, impurities contained in the silicon carbide powder include aluminum (Al), boron (B), calcium (Ca), cobalt (Co), chromium (Cr), iron (Fe), magnesium (Mg), and sodium (Na) , Nickel (Ni), titanium (Ti), tungsten (W), vanadium (V), and the like.

Experimental Example 1.

In order to prepare the silicon carbide powder of Experimental Example 1, dry silica and a phenol resin were respectively mixed as a silicon source and a carbon source, and the mixed powder was carbonized at a temperature condition of 850 ° C, and then the temperature condition of 1700 ° C was 3 hours. While maintaining, the silicon-based gas, SiH4 gas, is injected at 10 sccm to synthesize fine silicon carbide powder. In addition, by using this, a grain growth process is maintained for 5 hours at a temperature of 2100 ° C to prepare a silicon carbide powder of granulation.

The granulated silicon carbide powder thus prepared, as shown in Table 1 above, has a purity (impurity content in the powder) of 0.97 ppm and a residual silicon content in the powder of 153 ppm. In addition, the particle size (D ₅₀ ) of the powder is 2.27 μm, and the dispersion (D ₉₀ / D ₁₀ ) is 3.2. In addition, the carbon weight in the silicon carbide lattice was 29.1%, and the carbon weight in the silicon carbide lattice was reduced compared to the comparative example. That is, the proportion of silicon in the powder increased.

Experimental Example 2

In order to prepare the silicon carbide powder of Experimental Example 2, dry silica and a phenol resin were respectively mixed as a silicon source and a carbon source, and the mixed powder was carbonized at a temperature condition of 850 ° C, and then the temperature condition of 1700 ° C was 3 hours. While maintaining, the silicon-based gas, SiH4 gas, is injected at 50 sccm to synthesize fine silicon carbide powder. In addition, by using this, a grain growth process is maintained for 5 hours at a temperature of 2100 ° C to prepare a silicon carbide powder of granulation.

The granulated silicon carbide powder thus prepared has a purity (impurity content in the powder) of 0.92 ppm and a residual silicon content in the powder of 180 ppm, as shown in Table 1 above. In addition, the particle size (D ₅₀ ) of the powder was 1.32 μm, and the dispersion (D ₉₀ / D ₁₀ ) was 3.6. In addition, the carbon weight in the silicon carbide lattice was 28.7%, and the carbon weight in the silicon carbide lattice was reduced compared to the comparative example. That is, the proportion of silicon in the powder increased.

Experimental Example 3.

In order to prepare the silicon carbide powder of Experimental Example 3, dry silica and a phenol resin were respectively mixed as a silicon source and a carbon source, and the mixed powder was carbonized at a temperature condition of 850 ° C, and then the temperature condition of 1700 ° C was 3 hours. To maintain and synthesize fine silicon carbide powder. In addition, the synthesized silicon carbide powder is granulated by maintaining the temperature condition of 2100 ° C for 5 hours and injecting and growing the SiH4 gas, which is a silicon-based gas, at 10 sccm to give grain growth.

The granulated silicon carbide powder thus prepared has a purity (impurity content in the powder) of 0.42 ppm and a residual silicon content in the powder of 120 ppm, as shown in Table 1 above. In addition, the particle size (D ₅₀ ) of the powder is 232 μm, and the dispersion (D ₉₀ / D ₁₀ ) is 2.6. In addition, the carbon weight in the silicon carbide lattice was 29.9%, compared to the comparative example, the carbon weight in the silicon carbide lattice was reduced and the proportion of silicon in the powder was increased.

Experimental Example 4.

In order to prepare the silicon carbide powder of Experimental Example 4, dry silica and a phenol resin were respectively mixed as a silicon source and a carbon source, and the mixed powder was carbonized at a temperature condition of 850 ° C, followed by a temperature condition of 1700 ° C for 3 hours. To maintain and synthesize fine silicon carbide powder. In addition, the granulated silicon carbide powder is maintained by maintaining the temperature condition of 2100 ° C for 5 hours, and the silicon-based gas of SiH4, which is a silicon-based gas, is injected and grown by 50 sccm to prepare granulated silicon carbide powder.

The granulated silicon carbide powder thus prepared has a purity (impurity content in the powder) of 0.52 ppm and a residual silicon content in the powder of 127 ppm, as shown in Table 1 above. In addition, the particle size (D ₅₀ ) of the powder is 244.2 µm, and the dispersion (D ₉₀ / D ₁₀ ) is 2.6. In addition, the carbon weight in the silicon carbide lattice was 29.6%, compared to the comparative example, the carbon weight in the silicon carbide lattice was reduced and the proportion of silicon in the powder was increased.

Experimental Example 5.

In order to prepare the silicon carbide powder of Experimental Example 5, dry silica and a phenol resin were respectively mixed as a silicon source and a carbon source, and the mixed powder was carbonized at a temperature condition of 850 ° C, followed by a temperature condition of 1700 ° C for 3 hours. While maintaining, SiS4 gas, a silicon-based gas, is injected at 10 sccm to synthesize fine silicon carbide powder. In addition, the synthesized silicon carbide powder is granulated by maintaining the temperature condition of 2100 ° C for 5 hours and injecting and growing the SiH4 gas, which is a silicon-based gas, at 10 sccm to give grain growth.

The granulated silicon carbide powder thus prepared, as shown in Table 1 above, has a purity (impurity content in the powder) of 0.74 ppm and a residual silicon content in the powder of 185 ppm. In addition, the particle size (D ₅₀ ) of the powder is 241.2 μm, and the dispersion (D ₉₀ / D ₁₀ ) is 2.19. In addition, the carbon weight in the silicon carbide lattice was 28.6%, compared to the comparative example, the carbon weight in the silicon carbide lattice was reduced and the proportion of silicon in the powder was increased.

Experimental Example 6.

In order to prepare the silicon carbide powder of Experimental Example 6, dry silica and a phenol resin were respectively mixed as a silicon source and a carbon source, and after carbonizing the mixed powder at a temperature condition of 850 ° C, the temperature condition of 1700 ° C was 3 hours. While maintaining, the silicon-based gas SiH4 gas is injected at 50 sccm to synthesize fine silicon carbide powder. In addition, the granulated silicon carbide powder is maintained by maintaining the temperature condition of 2100 ° C for 5 hours, and the silicon-based gas of SiH4, which is a silicon-based gas, is injected and grown by 50 sccm to prepare granulated silicon carbide powder.

The granulated silicon carbide powder thus prepared, as shown in Table 1 above, has a purity (impurity content in the powder) of 0.49 ppm and a residual silicon content in the powder of 192 ppm. In addition, the particle size (D ₅₀ ) of the powder is 238.1 μm, and the dispersion (D ₉₀ / D ₁₀ ) is 2.48. In addition, the carbon weight in the silicon carbide lattice was 28.1%, compared to the comparative example, the carbon weight in the silicon carbide lattice was reduced and the proportion of silicon in the powder was increased.

As described above, according to an embodiment of the present invention, any one of the synthetic process of synthesizing particulate silicon carbide and the particle growth process of producing granular silicon carbide powder by grain growth of particulate silicon carbide powder are performed While, silicon-rich silicon carbide powder can be obtained by injecting a silicon-based gas.

In general, most of the consumables, except for seeds, are made of graphite during single crystal growth, and thus a carbon-rich atmosphere may be formed in the sublimated gas. When a carbon-rich atmosphere is formed, the carbon cluster may cause carbon inclusion inside the crystal, which may be converted into a polytype or other defect.

In addition, loss of silicon gas occurs in the early stage of single crystal growth, which may lead to a decrease in crystal growth rate, and formation of unstable stoichiometry, which may lead to a decrease in the quality of a silicon carbide single crystal in which growth is important. .

Therefore, when growing a single crystal using a silicon-rich silicon carbide powder prepared according to an embodiment of the present invention, high-quality single crystal growth is possible by suppressing defects caused by carbon and forming a stable stoichiometric coefficient.

In addition, by compensating for the loss of the initial silicon gas, more efficient powder sublimation is possible, and thus there is an effect that high-speed growth of a single crystal is possible. In addition, the ratio of silicon to carbon (Si / C ratio) is high, which is advantageous for growing 6H-silicon carbide single crystals.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You can understand that you can.

Claims (8)

A mixing step of preparing a mixed powder by mixing a carbon source and a silicon source;
A heat treatment step of heat-treating the mixed powder to synthesize fine silicon carbide powder;
And a particle growth step of heat-treating the fine silicon carbide powder to form granulated silicon carbide powder,
The heat treatment step,
Carbonization process for heat-treating the mixed powder at 600 ° C to 1200 ° C,
It includes a synthetic process for heat treatment of the mixed powder at 1300 ° C to 1900 ° C,
The synthesis process is produced by a method of manufacturing silicon carbide powder in which argon and silicon-based gases, which are inert gases, are injected into the mixed powder,
Silicon carbide powder having an impurity content of 1 ppm or less and a weight ratio of carbon in the silicon carbide lattice of 30% or less. According to claim 1,
Silicon carbide powder in which the weight ratio of carbon in the silicon carbide lattice is 28% or more and less than 30%. According to claim 1,
Silicon carbide powder having the impurity content of 0.5 ppm or less. According to claim 1,
Silicon carbide powder having a residual silicon content of 200 ppm or less in the silicon carbide powder. According to claim 1,
Silicon carbide powder having a particle size (D ₅₀ ) of 100 μm to 500 μm. According to claim 1,
Silicon carbide powder having a particle size (D ₅₀ ) of 0.5 μm to 10.0 μm. The method according to claim 5 or 6,
Silicon carbide powder having a dispersion (D ₉₀ / D ₁₀ ) of 2 to 5. According to claim 1,
The silicon-based gas is SiH 4 silicon carbide powder.

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