KR20150087965A - Preparing method of silicon carbide powder - Google Patents

Abstract

An embodiment of the present invention relates to a method for preparing silicon carbide powder having improved packing density and a method for growing a single crystal by using the same. The method for preparing silicon carbide powder according to an embodiment of the present invention comprises the steps of: preparing silicon carbide seeds having a particle size of 1-10 μm; packing the silicon carbide seeds in a crucible; and pressurizing the crucible, wherein the crucible is pressurized with a pressure of 50-150 Mpa.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing a silicon carbide powder,

An embodiment relates to a method for producing a silicon carbide powder.

In general, the importance of materials in the fields of electric, electronic industry, and machine parts is very high, which is an important factor in determining the characteristics and performance indices of actual final parts.

Si, used as a typical semiconductor device material, is susceptible to temperatures above 100 degrees Celsius, which causes frequent malfunctions and failures, thus requiring a variety of cooling devices. As Si shows such physical limitations, broadband semiconductor materials such as SiC, GaN, AlN and ZnO are attracting attention as next-generation semiconductor device materials.

Silicon carbide (SiC) is superior to GaN, AlN and ZnO in terms of thermal stability and oxidation resistance. In addition, silicon carbide has an excellent thermal conductivity of about 4.6 W / Cm ° C and can be produced as a substrate having a diameter of 2 inches or more. Particularly, silicon carbide single crystal growth technology is realistically most stable, and industrial production technology is the most advanced as a substrate.

Generally, silicon carbide powder is used as a raw material in the growth of the silicon carbide single crystal. In detail, silicon carbide powder is filled in a crucible of a single crystal growth apparatus, and a silicon carbide single crystal is grown by a pressurization and heating process, and then the silicon carbide single crystal is sliced to produce a silicon carbide wafer.

At this time, in order to grow the silicon carbide single crystal, the silicon carbide powder is filled in the crucible. At this time, granular silicon carbide powder having a particle diameter of about 100 mu m or more is used. That is, in the case of the microcrystalline silicon carbide powder having a particle size of about 0.1 μm to 10 μm, although the growth rate can be improved, scattering may occur during the process, and the gap between the powders becomes wider according to the electrostatic attraction between the powders, The granular silicon carbide powder having a particle diameter of about 100 mu m or more is used in the production of silicon carbide wafers.

Accordingly, there is a need for a method for producing silicon carbide powder that can improve the packing density even when fine silicon carbide powder is used for growing silicon carbide single crystal.

The present invention provides a method for producing silicon carbide powder having an improved filling density and a method for growing a single crystal using the same.

The method for producing a silicon carbide powder according to the embodiment comprises the steps of: preparing a silicon carbide seed having a particle diameter of 1 탆 to 10 탆; Filling the crucible with the silicon carbide seed; And pressing the crucible, wherein the crucible is pressurized to a pressure of 50 Mpa to 150 Mpa.

According to an embodiment of the present invention, there is provided a method of manufacturing a silicon carbide single crystal, comprising: preparing a silicon carbide powder having a particle diameter of 1 탆 to 10 탆; Filling the crucible with the silicon carbide powder; Pressing the crucible; Introducing the crucible into a single crystal growth apparatus; And heating the single crystal growth apparatus, wherein the crucible is pressurized to a pressure of 50 MPa to 150 MPa.

The silicon carbide powder produced by the method for producing silicon carbide powder according to the embodiment can increase the packing density and loading amount when the powder is introduced into the crucible even if it is a fine silicon carbide powder.

That is, by charging the silicon carbide seed into the crucible and pressurizing the crucible, the silicon carbide seeds are agglomerated to reduce the gap between the silicon carbide seeds, whereby the amount of silicon carbide powder charged into the crucible and the amount of the silicon carbide powder charged into the crucible can be improved.

Accordingly, even if the fine silicon carbide powder having a particle size of 1 占 퐉 to 10 占 퐉 is used without using the granular silicon carbide powder having a particle size of 100 占 퐉 or more, the filling density and the charging amount in the crucible can be improved, Silicon single crystal growth can be performed, and thus the growth rate can be improved in single crystal growth.

Therefore, the silicon carbide powder according to the embodiment can improve the filling efficiency and the filling efficiency by forming the fine silicon carbide powder according to the embodiment, thereby improving the process efficiency in single crystal growth.

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 state in which a conventional silicon carbide powder is filled in a crucible.
3 is a view showing a state in which the silicon carbide powder according to the embodiment is filled in the crucible.
4 is a view showing a state in which a silicon carbide powder and a silicon carbide precursor according to the embodiment are mixed and filled in a crucible.
5 is a view showing a single crystal growing apparatus using silicon carbide powder 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.

A method of manufacturing silicon carbide powder according to an embodiment will be described with reference to Figs. 1 to 4. Fig.

Referring to FIG. 1, a method of manufacturing a silicon carbide powder according to an embodiment includes steps of preparing a silicon carbide seed (ST10), filling a crucible with a silicon carbide seed (ST20), and pressing a crucible (ST30) .

In the step (ST10) of preparing the silicon carbide seed, a silicon carbide seed having a particle diameter within a certain range can be prepared. The silicon carbide seed may be a silicon carbide powder. In detail, the silicon carbide seed may be a silicon carbide powder having a particle diameter of about 1 탆 to about 10 탆.

The silicon carbide seed 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.

The carbon source may comprise a solid carbon source or an organic carbon compound.

Examples of the solid carbon source include graphite, carbon black, carbon nano tube (CNT), and fullerene (C ₆₀ ).

Examples of the organic carbon compound include phenol, franc, xylene, polyimide, polyunrethane, polyvinyl alcohol, polyacrylonitrile, Poly (vinyl acetate), and the like. In addition, cellulose, sugar, pitch, tar and the like can be used.

The carbon source and the silicon source can be mixed by a wet mixing process using a solvent or a dry mixing process without using a solvent.

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

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.

Then, a synthesis step is carried out. That is, the mixed powder containing the silicon source and the carbon source may be heated to form the silicon carbide powder. The synthesis step may be divided into a carbonization step and a synthesis step.

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. At this time, it is possible to make the silicon carbide powder to have a beta phase, which is a low-temperature stable phase, by adjusting the heating temperature to about 1300 ° C to about 1900 ° C. Such a beta phase is formed of fine particles, which can improve the strength and the like of the silicon carbide powder. However, the present invention is not limited thereto, and it is needless to say that the silicon carbide powder may have an alpha phase which is a high-temperature stabilizing phase, with the heating temperature exceeding about 1900 ° C. The synthesis process may proceed for about 2 to 4 hours.

The silicon carbide seed having a particle diameter of about 1 탆 to about 10 탆 can be produced by the above-described manufacturing process.

Then, in the step of filling the crucible with the silicon carbide seed (ST20), the crucible may be filled with the silicon carbide seed having a particle diameter of about 1 mu m to about 10 mu m.

The crucible may comprise a material capable of withstanding high temperatures. That is, the crucible may include a material having a melting point higher than a sublimation temperature of silicon carbide. In one example, the crucible may comprise graphite. Further, the crucible may have a cylindrical shape.

Subsequently, in the step (ST30) of pressing the crucible, the crucible can be pressurized to a certain range of pressure. The crucible may be pressurized in a variety of ways. For example, the crucible can be pressurized by one-side press forming, warm press, CIP and hpt press methods.

The crucible may be pressurized to a pressure of about 100 MPa to about 200 MPa. Preferably, the crucible may be pressurized to a pressure of about 50 MPa to 150 MPa. If the crucible is pressurized to less than about 50 MPa, the silicon carbide seed may not sufficiently aggregate, and if the crucible is pressurized to more than about 150 MPa, the process efficiency may be lowered.

The crucible may be pressurized for about 30 seconds to about 1 minute. In detail, the crucible can be pressurized at a maximum pressure holding time of about 30 seconds to about 1 minute.

As the crucible is pressed. The filling density of the silicon carbide seed to be filled in the crucible can be improved. That is, the silicon carbide seed packing density when the silicon carbide seed is filled in the crucible and the silicon carbide seed packing density when the silicon carbide seed is filled after the crucible are pressed may be different from each other.

For example, the filling density of the silicon carbide powder produced by the method for preparing silicon carbide powder according to the embodiment may be about 1.95 g / cm3 to about 2.18 g / cm3.

2, when the silicon carbide seed 200 is simply filled in the crucible 100, the silicon carbide seed having fine particles of about 1 to about 10 탆 arranged in the crucible may be a fine particle The gap between the particles is widened by the frictional force between the particles and the electrostatic attraction, and the filling efficiency may be lowered.

However, referring to FIG. 3, when the silicon carbide seed is filled in the crucible and then pressurized by a certain range of pressure, the silicon carbide seeds disposed in the crucible cohere to each other, , So that intergranular voids become smaller and the filling efficiency can be improved.

As a result, the amount of silicon carbide powder to be charged into the crucible can be increased, and as the fine particles are used, the growth rate can be increased during the single crystal growth to improve the growth efficiency.

In the method of producing silicon carbide powder according to the embodiment, a silicon carbide precursor may be further added to the silicon carbide seed. In detail, after the silicon carbide seed is filled in the crucible (ST20), the silicon carbide precursor can be further injected into the crucible.

The silicon carbide precursor may include carbon and silicon. In one example, the silicon carbide precursor may comprise at least one precursor of polycarbosilane and silazane. The silicon carbide precursor may be put into a solid or liquid phase.

The silicon carbide precursor may be introduced into the crucible and mixed with the silicon carbide seed. Thereafter, after the silicon carbide precursor is further introduced, the crucible can be pressurized to a pressure of about 100 MPa to about 200 MPa. Preferably, the crucible may be pressurized to a pressure of about 50 MPa to 150 MPa. When the crucible is pressurized to less than about 50 MPa, the silicon carbide seed and the silicon carbide precursor may not sufficiently aggregate, and if the crucible is pressurized to more than about 150 MPa, the process efficiency may be lowered.

The crucible may be pressurized for about 30 seconds to about 1 minute. In detail, the crucible can be pressurized at a maximum pressure holding time of about 30 seconds to about 1 minute.

Then, in order to remove organic matter from the silicon carbide precursor, the crucible may be heated. In detail, the crucible may be heated to a temperature of about 1300 ° C to about 1500 ° C. Accordingly, organic substances contained in the silicon carbide precursor can be changed to a gaseous state and removed.

4, when the silicon carbide seed 200 and the silicon carbide precursor 300 are filled in a crucible and pressurized by a certain range of pressure, the silicon carbide seeds disposed in the crucible coagulate with each other , The fine particles can be aggregated with each other, and accordingly, the voids between the particles can be made small, so that the filling efficiency can be improved.

Further, since the silicon carbide precursor is included in addition to the silicon carbide seed, the filling amount of the silicon carbide powder in the crucible can be further improved and the filling density can be improved.

As a result, the amount of silicon carbide powder to be charged into the crucible can be increased, and as the fine particles are used, the growth rate can be increased during the single crystal growth to improve the growth efficiency.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to the methods for producing silicon carbide powder according to Examples and Comparative Examples. 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

The crucible was filled with a silicon carbide seed having a particle diameter of about 1 mu m, and the crucible was pressed at a pressure of about 50 MPa.

At this time, when the crucible was pressed, the maximum pressure holding time was about 1 minute.

Then, the filling density of the silicon carbide powder to be filled in the crucible and the charging amount in the crucible were measured.

Example 2

The silicon carbide seed was charged into the crucible in the same manner as in Example 1, except that the crucible was pressurized at a pressure of about 150 MPa when the crucible was pressed, and the filling density of the silicon carbide powder filled in the crucible and the crucible And the amount of internal load was measured.

Example 3

The silicon carbide seed was charged into the crucible in the same manner as in Example 1 except that the crucible was pressurized at a pressure of about 150 MPa and the maximum pressure holding time was about 5 minutes, The filling density of the silicon powder and the charging amount in the crucible were measured.

Example 4

A silicon carbide seed having a particle diameter of about 2 mu m was filled in the crucible and the crucible was pressurized at a pressure of about 150 MPa, the silicon carbide seed was charged into the crucible in the same manner as in Example 1, The filling density of the silicon carbide powder to be filled and the charging amount in the crucible were measured.

Example 5

A silicon carbide seed having a particle diameter of about 10 mu m was filled in a crucible and the crucible was pressed at a pressure of about 150 MPa, the silicon carbide seed was charged into the crucible in the same manner as in Example 1, The filling density of the silicon carbide powder to be filled and the charging amount in the crucible were measured.

Example 6

The crucible was filled with a silicon carbide seed having a particle diameter of about 1 mu m and a silicon carbide precursor including polycarbosilane and silazane, and the crucible was pressed at a pressure of about 50 MPa.

At this time, the silicon carbide precursor was added by about 10% by weight to the entire silicon carbide seed and the silicon carbide precursor to be filled in the crucible.

At this time, when the crucible was pressed, the maximum pressure holding time was about 1 minute.

Subsequently, the crucible was heated at a temperature of about 1600 DEG C at a heating temperature of 2 DEG C / min.

Then, the filling density of the silicon carbide powder to be filled in the crucible and the charging amount in the crucible were measured.

Example 7

The silicon carbide seed was charged into the crucible in the same manner as in Example 6 except that the silicon carbide seed had a particle diameter of about 2 탆 and the filling density of the silicon carbide powder filled in the crucible and the charging amount inside the crucible were Respectively.

Example 8

The silicon carbide seed was charged into the crucible in the same manner as in Example 6, except that the silicon carbide precursor was added by about 20% by weight based on the entire silicon carbide seed and silicon carbide precursor, and the silicon carbide powder And the charging amount in the crucible were measured.

Example 9

Except that the silicon carbide seed had a particle size of about 2 탆 and the silicon carbide precursor was added by about 20% by weight based on the entire silicon carbide seed and the silicon carbide precursor, And the filling density of the silicon carbide powder to be filled in the crucible and the charging amount in the crucible were measured.

Comparative Example 1

A silicon carbide seed having a particle size of about 1 mu m was charged into the crucible and the filling density of the silicon carbide powder to be filled in the crucible and the loading amount in the crucible were measured without a pressing process.

Comparative Example 2

A silicon carbide seed having a particle diameter of about 2 mu m was charged into the crucible and the filling density of the silicon carbide powder to be filled in the crucible and the loading amount in the crucible were measured without a pressing process.

Filling density (g / cm3) Charge amount in the crucible (g) Example 1 1.28 900 Example 2 1.31 960 Example 3 1.33 970 Example 4 1.45 1070 Example 5 1.85 1430 Example 6 1.95 1560 Example 7 2.03 1590 Example 8 2.08 1620 Example 9 2.18 1680 Comparative Example 1 1.20 820 Comparative Example 2 1.40 1000

Referring to Table 1, in Examples 1 to 5, the filling density of the silicon carbide powder charged into the crucible and the charging amount inside the crucible are improved as compared with Comparative Examples 1 and 2.

That is, by charging the silicon carbide seed into the crucible and pressurizing the crucible, the silicon carbide seeds are agglomerated to reduce the gap between the silicon carbide seeds, whereby the amount of silicon carbide powder charged into the crucible and the amount of the silicon carbide powder charged into the crucible can be improved.

Accordingly, even if the fine silicon carbide powder having a particle size of 1 占 퐉 to 10 占 퐉 is used without using the granular silicon carbide powder having a particle size of 100 占 퐉 or more, the filling density and the charging amount in the crucible can be improved, Silicon single crystal growth can be performed, and thus the growth rate can be improved in single crystal growth.

Therefore, the silicon carbide powder according to the embodiment can improve the filling efficiency and the filling efficiency by forming the fine silicon carbide powder according to the embodiment, thereby improving the process efficiency in single crystal growth.

Hereinafter, with reference to FIG. 5, a method for growing a silicon carbide single crystal according to an embodiment will be described.

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

The steps of preparing the silicon carbide powder, filling the crucible with the silicon carbide powder, and pressing the crucible are the same as those of the silicon carbide powder manufacturing method described above, and therefore, the following description is omitted.

In the step of injecting the crucible into the single crystal growth apparatus, the crucible 100 filled with the silicon carbide powder 200 produced by pressurizing the crucible may be introduced into the single crystal growth apparatus 1000. At this time, the crucible can be directly fed into the single crystal growth apparatus without using a separate crucible, that is, when the silicon carbide powder is produced, that is, the crucible is pressurized.

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 and 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.

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 (10)

Preparing a silicon carbide seed having a particle diameter of 1 占 퐉 to 10 占 퐉;
Filling the crucible with the silicon carbide seed;
And pressing the crucible,
Wherein the crucible is pressurized to a pressure of 50 MPa to 150 MPa. The method according to claim 1,
Wherein the silicon carbide powder has a packing density of 1.2 g / cm3 to 1.85 g / cm3 in the crucible. The method according to claim 1,
After filling the crucible with the silicon carbide seed,
And adding a silicon carbide precursor to the crucible to form a mixture. The method of claim 3,
Wherein the silicon carbide seed and the silicon carbide precursor are mixed at a temperature of 1300 ° C to 1500 ° C. The method of claim 3,
Wherein the mixture has a packing density of 1.95 g / cm3 to 2.18 g / cm3 in the crucible. Preparing a silicon carbide powder having a particle diameter of 1 占 퐉 to 10 占 퐉;
Filling the crucible with the silicon carbide powder;
Pressing the crucible;
Introducing the crucible into a single crystal growth apparatus; And
And heating the single crystal growth apparatus,
Wherein the crucible is pressurized to a pressure of 50 MPa to 150 MPa. The method according to claim 6,
Wherein the silicon carbide powder has a packing density of 1.2 g / cm3 to 1.85 g / cm3 in the crucible. The method according to claim 6,
After filling the crucible with the silicon carbide powder,
And adding a silicon carbide precursor to the crucible to form a mixture. 9. The method of claim 8,
Wherein the silicon carbide powder and the silicon carbide precursor are mixed at a temperature of 1300 ° C to 1500 ° C. 9. The method of claim 8,
Wherein the mixture has a packing density of 1.95 g / cm3 to 2.18 g / cm3 in the crucible.

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