KR20170080290A - Silicon carbide powder and method of fabrication the same - Google Patents

Abstract

The method of manufacturing a silicon carbide powder according to an embodiment includes mixing a carbon source and a silicon source to form a mixed powder; And synthesizing the mixed powder, wherein the mixed powder has an apparent density of 0.6 g / cm3 to 1.2 g / cm3.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a silicon carbide powder,

Embodiments relate to silicon carbide powder and a method of manufacturing the same.

Silicon carbide powder has recently been used as a semiconductor material for various electronic devices and purposes. Silicon carbide powders are particularly useful due to their physical strength and high resistance to chemical attack. Silicon carbide powders can also be used in a variety of applications including, but not limited to, radiation hardness, a relatively wide bandgap, a high saturated electron drift velocity, a high operating temperature, and blue, violet, and ultraviolet Quot;) < / RTI > region.

The silicon carbide powder may be produced by a variety of methods, for example, the Acheson method, the carbon thermal reduction method, the liquid polymer thermal decomposition method, or the CVD method. Particularly, the high-purity silicon carbide powder synthesis method uses a liquid phase polymer decomposition method or a carbon thermal reduction method.

That is, the silicon carbide powder can be synthesized by mixing the carbon source and the silicon source material, and performing the carbonization process and the synthesis process of the mixture.

Using the silicon carbide powder thus produced, a silicon carbide single crystal can be produced. At this time, the quality of the single crystal can be changed by the silicon carbide powder serving as a raw material of the silicon carbide single crystal.

Accordingly, there is a need for a method for producing silicon carbide powder capable of reducing defects in the growth of silicon carbide single crystals.

The embodiments are intended to provide a method for producing silicon carbide powder having improved quality and a silicon carbide powder produced thereby.

The method of manufacturing a silicon carbide powder according to an embodiment includes mixing a carbon source and a silicon source to form a mixed powder; And synthesizing the mixed powder, wherein the mixed powder has an apparent density of 0.6 g / cm3 to 1.2 g / cm3.

The silicon carbide powder according to the embodiment can control the apparent density of the mixed powder which is a precursor of the silicon carbide powder to uniformize the particle diameters of the silicon carbide powder to be produced.

Thus, by uniformizing initial nucleation according to the heating rate during single crystal growth, the quality of the single crystal silicon carbide can be improved.

In addition, when the silicon carbide single crystal is grown using the silicon carbide powder according to the embodiment, the filling amount in the crucible can be improved and the process efficiency can be improved.

1 is a view showing a process flow chart of a method for producing silicon carbide powder according to an embodiment.
2 is a view showing a single crystal growing apparatus using the silicon carbide powder according to the embodiment.
3 is a photograph of a surface of a silicon carbide single crystal according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under / under" Quot; includes all that is formed directly or through another layer. The criteria for top / bottom or bottom / bottom of each layer are described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, the method for producing silicon carbide powder according to an embodiment may include a step ST10 of forming a mixed powder and a step ST20 of synthesizing the mixed powder.

In the step (ST10) of forming the mixed powder, a mixed powder may be prepared by mixing a carbon source and a silicon source.

The silicon source may include various materials capable of providing silicon. For example, the silicon source may comprise silica. In addition to the silica, the silica source may be silica powder, silica sol, silica gel, quartz powder, or the like. However, the embodiment is not limited thereto, and an organosilicon compound containing silicon may be used as a silicon source.

In addition, the carbon source may include a solid carbon source or an organic carbon compound.

The solid carbon source may include at least one of graphite, carbon black, carbon nano tube (CNT), and fullerene (C ₆₀ ).

Examples of the organic carbon compounds include phenol, franc, xylene, polyimide, polyunrethane, polyvinyl alcohol, polyacrylonitrile, And polyvinyl acetate (poly (vinyl acetate)). Cellulose, sugar, pitch, or tar, and the like.

These silicon sources and carbon sources can be mixed by ball mill, attrition bill or the like to recover the mixed powder. The mixed powder may be recovered by being caught by a sieve or the like.

The silicon source and the carbon source may be mixed at a certain ratio. For example, the mole ratio of carbon contained in the carbon source to silicon contained in the silicon source (hereinafter referred to as " mole ratio of carbon to silicon ") may be from about 1: 1.5 to about 1: 3. When the molar ratio of carbon to silicon is more than about 3, the amount of carbon is large, so that the amount of residual carbon remaining does not participate in the reaction and the recovery rate may be lowered. When the molar ratio of carbon to silicon is less than about 1.5, the amount of residual silicon remaining in the reaction does not participate in the reaction due to a large amount of silicon, which may reduce the recovery rate. That is, the molar ratio of carbon to silicon is determined in consideration of the recovery rate.

At this time, considering that the silicon source volatilizes in a gaseous state at a high temperature in the reaction step, the molar ratio of carbon to silicon may be about 1.8 to about 2.7.

The silicon source and the carbon source may be mixed by the above process to form a mixed powder containing carbon and silicon.

The apparent density of the mixed powder may be about 0.6 g / cm 3 or more. In detail, the mixed powder may have an apparent density of about 0.6 g / cm 3 to 1.2 g / cm 3.

The density of the powder can be divided into the apparent density and the tap density depending on the presence or absence of the treatment. The apparent density can be defined as the amount of powder per unit volume. The tap density may be defined as the density measured after tapping after charging the powder into the crucible.

That is, the apparent density is a pre-tack density of the powder charged in the crucible, and the tap density may mean density after tapping of the powder.

That is, the height of the powder in the crucible measured at the time of measuring the apparent density and the height of the powder measured at the tap density measurement may be different. In detail, the height of the powder in the crucible measured at the time of measuring the apparent density may be greater than the height of the powder measured at the tap density measurement.

The apparent density of the mixed powder may be related to the dispersion of the silicon carbide powder produced by synthesizing the mixed powder. In detail, the mixed powder has an apparent density of about 0.6 g / cm 3 or more, thereby reducing the scattering of the silicon carbide powder produced by the mixed powder, so that the silicon carbide powder having a uniform particle diameter can be produced.

Next, in the step of forming the silicon carbide powder by synthesizing the mixed powder, the mixed powder may be reacted at a constant temperature and pressure.

The step of synthesizing the mixed powder (ST20) may be classified into a carbonization process and a synthesis process.

In the carbonization process, the organic carbon compound may be carbonized to generate carbon. The carbonization process may be performed at a temperature of about 600 ° C to about 1200 ° C. More specifically, the carbonization process may proceed at a temperature of about 800 ° C to about 1100 ° C. When the solid carbon source is used as a carbon source, the carbonization process may not proceed.

Thereafter, the above-described synthesis process proceeds. In the synthesis step, the silicon source reacts with the solid carbon source, or the silicon source reacts with the organic carbon compound, and the silicon carbide powder may be formed according to the overall reaction formula of the reaction formula 3 according to the following reaction formulas 1 and 2 have.

[Reaction Scheme 1]

SiO2 (s) + C (s) - > SiO (g) + CO (g)

[Reaction Scheme 2]

SiO (g) + 2C (s) - > SiC (s) + CO (g)

[Reaction Scheme 3]

SiO2 (s) + 3C (s) - > SiC (s) + 2CO (g)

The heating temperature may be about 1300 ° C or higher so that the reaction as described above can be smoothly performed. In detail, the heating temperature may be about 1300 ° C to about 1900 ° C. More specifically, the heating temperature may be from about 1400 ° C to about 1800 ° C.

The mixed powder is synthesized by the above-mentioned synthesis step, and a beta-phase silicon carbide powder which is a low-temperature stable phase can be produced. In detail, the silicon carbide powder may be a fine powder. For example, the silicon carbide powder may be a beta-phase silicon carbide powder having a particle size of about 0.1 mu m to about 10 mu m.

The silicon carbide powder may have a circular, elliptical or spherical shape.

The silicon carbide powder may have a certain dispersion. In detail, the silicon carbide powder may have a dispersion of from about 2 to about 5. That is, since the silicon carbide powder has small scattering, the particle size of the silicon carbide powder can be uniform.

Accordingly, when the silicon carbide powder is used as the silicon carbide powder for monocrystalline growth, the amount of the powder to be filled in the crucible can be increased. In addition, dust generation can be reduced, and recovery can be improved. In addition, it is possible to prevent the silicon carbide powder from being vaporized at different sublimation temperatures in accordance with variations in particle size of the silicon carbide powder.

Therefore, when the silicon carbide powder is used as the silicon carbide powder for monocrystal growth, single crystal defects can be reduced and the process efficiency can be improved.

Hereinafter, a method for growing a silicon carbide single crystal according to an embodiment will be described with reference to FIG.

A method for growing a silicon carbide single crystal according to an embodiment includes the steps of preparing a silicon carbide powder for single crystal growth, filling the crucible with the silicon carbide powder, injecting the crucible into a single crystal growth apparatus, And heating.

The step of preparing the silicon carbide powder for single crystal growth is the same as the above-described method of producing silicon carbide powder, and the description thereof will be omitted.

Then, the crucible for filling the crucible 100 with the silicon carbide powder for single crystal growth can be supplied to the single crystal growth apparatus 1000.

Subsequently, in the step of heating the single crystal growth apparatus, heat can be applied to the crucible 100. Although not shown in the drawing, a heat induction unit may be located outside the crucible 100 to apply heat to the crucible 100. The crucible 100 may generate heat by itself by the heat induction unit. The heat induction unit may be, for example, a high frequency induction coil. The crucible 100 can be heated by flowing a high frequency current through the high frequency induction coil. That is, the raw material contained in the crucible 100 can be heated to a desired temperature.

The silicon carbide powder contained in the crucible 100 is sublimated and can move to the seed crystal 400 in the crucible 100 and the ingot 410 can grow from the seed crystal 400. [

Specifically, a temperature gradient having different heating temperature regions is formed in the upper portion and the lower portion of the crucible 100 by the heating inducing portion. Due to this temperature gradient, sublimation of the silicon carbide powder occurs, and the sublimated silicon carbide gas moves to the surface of the seed crystal 400 having a relatively low temperature. As a result, the silicon carbide gas can be recrystallized and grown as the ingot 410.

As described above, the silicon carbide single crystal growth according to the embodiment can use the finely divided beta-phase silicon carbide powder having a uniform particle size.

As a result, the amount of silicon carbide powder to be filled in the crucible can be increased and the process efficiency can be improved.

In addition, as the particle size of the silicon carbide powder is uniform, the amount of nucleation that is initially generated becomes uniform as the sublimation temperature becomes constant, so that defects of the silicon carbide single crystal can be reduced and the quality can be improved.

Hereinafter, the present invention will be described in more detail with reference to the method for producing silicon carbide powder according to the embodiments. These embodiments are merely illustrative of the present invention in order to explain the present invention in more detail. Therefore, the present invention is not limited to these embodiments.

Example 1

10 g of fumed silica and 10 g of phenol resin were mixed to form a mixed powder. In addition, 6 kg of the raw material was put into a crucible 500? X 100H.

The mixing device was a device equipped with an impeller and operated at an impeller speed of 200 rpm for 5 hours to prepare a mixed powder.

Thereafter, the mixed powder was subjected to a carbonization process at a temperature rise of 3 ° C / min at a temperature of about 850 ° C for 2 hours, a synthesis process at a temperature of about 1650 ° C for about 90 minutes at a temperature increase rate of 5 ° C / To prepare a silicon carbide powder having a fine crystal phase.

Then, the apparent density, particle size and particle size distribution of the silicon carbide powder were measured.

Example 2

A silicon carbide powder was prepared in the same manner as in Example 1, except that the mixed powder was subjected to a synthesis process at a temperature rise rate of 5 ° C / min and a temperature of about 1650 ° C for about 150 minutes, The apparent density, particle size and particle size distribution of the sample were measured.

Example 3

The silicon carbide powder was prepared in the same manner as in Example 1, except that the mixed powder was subjected to a synthesis process at a temperature elevation temperature of 5 ° C / min and a temperature of about 1750 ° C for about 150 minutes, The apparent density, particle size and particle size distribution of the sample were measured.

Apparent density Particle size (D50) Particle size distribution (D90 / D10) Example 1 0.62 0.69 4.14 Example 2 0.92 1.41 3.15 Example 3 1.16 2.01 3.19

Referring to Table 1, it can be seen that the silicon carbide powder according to the examples has a fine particle size and a small scattering. That is, it can be seen that the silicon carbide powder according to the embodiments has a small particle size difference, that is, a uniform particle size.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to a method for producing a silicon carbide single crystal according to embodiments. These embodiments are merely illustrative of the present invention in order to explain the present invention in more detail. Therefore, the present invention is not limited to these embodiments.

Example 4

Using the silicon carbide powder of Example 1, silicon carbide single crystals were grown by the single crystal growth process.

Referring to FIG. 3, it can be seen that the silicon carbide single crystal of Example 4 has a small defect density. In detail, the defect density (MPD) of the silicon carbide single crystal was about 1.1 ea / cm 2.

That is, it can be seen that the quality of the silicon carbide single crystal can be improved by making the grain size of the silicon carbide powder for single crystal growth uniform.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (9)

Mixing a carbon source and a silicon source to form a mixed powder; And
And synthesizing the mixed powder,
Wherein the mixed powder has an apparent density of 0.6 g / cm3 to 1.2 g / cm3. The method according to claim 1,
Wherein the beta-phase silicon carbide powder is dispersed in an amount of 2 to 5 by weight. The method according to claim 1,
Wherein the beta-phase silicon carbide powder has a particle diameter of 0.1 mu m to 10 mu m. The method according to claim 1,
Wherein the silicon source comprises silica, silica powder, silica sol, silica gel or quartz powder,
The carbon source may be selected from the group consisting of graphite, carbon black, carbon nano tube (CNT), fullerene, C, phenol, franc, xylene, Polyimide, polyunrethane, polyvinyl alcohol, polyacrylonitrile, poly (vinyl acetate), cellulose, sugar, pitch or the like. A method for producing beta-phase silicon carbide powder comprising tar. The method according to claim 1,
Wherein the step of synthesizing the mixed powder proceeds at a temperature of 1300 ° C to 1900 ° C. A beta-phase silicon carbide powder produced by the method of any one of claims 1 to 5. 1. A silicon carbide powder for single crystal growth comprising a carbon source and a silicon source and having a grain size of 0.1 to 10 mu m. 8. The method of claim 7,
Wherein the silicon carbide powder for single crystal growth comprises a beta phase silicon carbide powder. 8. The method of claim 7,
Wherein the silicon carbide powder for monocrystal growth has a dispersion of 2 to 5 silicon carbide powder for single crystal growth.

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