KR102619072B1 - Manufacturing method for p-type siliconcarbide single crystal and p-type siliconcarbide single crystal - Google Patents

Abstract

The present invention is a method for producing a p-type silicon carbide single crystal,
The concentration change rate ratio of silicon (Si) and aluminum (Al) satisfies condition 1 below,
[Condition 1]

In the above equation,
[Al] ₀ is the Al atom concentration in the initially added raw material mixture,
[Al] _t is the concentration of Al atoms among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,
[Si] ₀ is the concentration of Si atoms in the initially added raw material mixture,
[Si] _t is the Si atom concentration among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,
Provided is a method for manufacturing a p-type silicon carbide single crystal and a p-type silicon carbide single crystal in which the concentration change rate of Si satisfies Condition 2 below.
[Condition 2]

In the above equation,
[Si] ₀ and [Si] _t are as defined above,
t is growth time (h).

Description

Manufacturing method of p-type silicon carbide single crystal and p-type silicon carbide single crystal {MANUFACTURING METHOD FOR P-TYPE SILICONCARBIDE SINGLE CRYSTAL AND P-TYPE SILICONCARBIDE SINGLE CRYSTAL}

The present invention relates to a method for manufacturing a p-type silicon carbide single crystal and a p-type silicon carbide single crystal.

Silicon carbide (SiC) is a thermally and chemically stable compound semiconductor. Compared to silicon (Si), silicon carbide has excellent band gap, breakdown voltage, electron saturation rate, and thermal conductivity. For this reason, it is widely used as a component material in semiconductor, electronic, automobile, and mechanical fields.

In particular, it is desirable to use a p-type SiC single crystal with low resistance in power devices such as IGBT (Insulated Gate Bipolar Transistor), which is a high breakdown voltage bipolar device. When manufacturing a P-type SiC single crystal, Al (aluminum) is usually doped as a dopant.

Meanwhile, as a method of manufacturing a silicon carbide single crystal, raw metals, including Si, are placed in a graphite crucible, the crucible is heated through induction heating to form a metal melt, and a seed crystal is brought into contact with the melt, resulting in supercooling. Research on solution growth methods to grow SiC single crystals on seed crystals using SiC crystal precipitation is active.

In the solution growth method, if the melt contains Al, a p-type SiC single crystal can be produced.

However, since pure Si solutions have very low carbon solubility, metal additives such as Cr are used, and single crystals are grown at a high temperature of 1900°C or higher using a multi-component melt with increased carbon solubility.

Since the crystal growth temperature is high as described above, evaporation of the multi-component solvent occurs during the crystal growth process, and there is a problem in that the composition of the solution changes. In particular, in the case of Al, which is added as a multi-component raw material for p-type SiC single crystal growth, it reacts sensitively to the process environment and Al concentration changes over time, which causes deviations in doping concentration, making it difficult to maintain a constant level during the long-term crystal growth process. There is a problem in that it is difficult to produce an ingot with specific resistance.

Therefore, there is an urgent need for a high-quality p-type SiC single crystal growth method that solves these problems and minimizes the deviation of resistivity in the growth direction even during long-term crystal growth and does not contain polycrystals or inclusions.

The present invention seeks to provide a method for manufacturing a low-resistance p-type SiC single crystal in which the change in thickness direction resistivity due to the change in Al doping concentration during growth is minimized even when single crystal growth is performed over a long period of time, and polycrystals or inclusions are not mixed. .

Additionally, the present invention provides a p-type SiC single crystal that has a long length in the growth direction of 3 mm or more, has a small change in resistivity in the thickness direction, and has low resistance.

The present invention is a method of manufacturing a p-type silicon carbide single crystal,

The concentration change rate ratio of silicon (Si) and aluminum (Al) satisfies condition 1 below,

[Condition 1]

In the above equation,

[Al] ₀ is the Al atom concentration in the initially added raw material mixture,

[Al] _t is the concentration of Al atoms among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,

[Si] ₀ is the concentration of Si atoms in the initially added raw material mixture,

[Si] _t is the concentration of Si atoms among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,

A method for manufacturing a p-type silicon carbide single crystal in which the Si concentration change rate satisfies Condition 2 below is provided.

[Condition 2]

In the above equation,

[Si] ₀ and [Si] _t are as defined above,

t is growth time (h).

Specifically, the method for manufacturing the p-type silicon carbide single crystal is,

Preparing a silicon carbide seed crystal;

Preparing a raw material mixture by mixing silicon (Si) raw material, aluminum (Al) raw material, and metal (M) additive raw material other than Al;

Heating the raw material mixture in a crucible to form a melt containing carbon (C); and

A step of growing a silicon carbide single crystal by contacting the seed crystal with the melt,

Growth of the silicon carbide single crystal can be performed continuously.

That is, conditions 1 and 2 above can be satisfied in continuous single crystal growth.

Here, the metal (M) may be one or more elements selected from the group consisting of Cr, Cu, Ti, Mn, Co, V, and Fe.

A method of forming the melt containing carbon may include using a graphite crucible or adding a separate carbon (C) raw material.

Heating to form the melt may be performed at 1700°C to 2200°C.

Growth of the silicon carbide single crystal may be performed at 1600°C to 2000°C.

The aluminum concentration in the melt during the growth of the silicon carbide single crystal may be maintained within 1 to 15 at% of elements other than carbon (C).

The manufactured p-type silicon carbide single crystal may be an ingot with a length in the growth direction of 3 mm or more, and the resistivity change rate may satisfy Equation 1 below.

[Equation 1]

The present invention also provides a p-type silicon carbide single crystal, wherein the p-type silicon carbide single crystal is an ingot with a length in the growth direction of 3 mm or more, a resistivity change rate that satisfies the following equation 1, and a resistivity of 100 mΩ·cm or less. You can.

[Equation 1]

According to the silicon carbide single crystal manufacturing method of the present invention, it is possible to manufacture a p-type silicon carbide single crystal ingot with a resistivity change rate (%/mm) of 10%/mm or less, a resistivity of 100 mΩ·cm or less, and a length in the growth direction of 3 mm or more. there is.

Figure 1 is a photograph of the appearance of a SiC single crystal manufactured by the method for manufacturing a silicon carbide single crystal according to Example 1.

Hereinafter, the present invention will be described in more detail to facilitate understanding of the present invention.

Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, terms such as “comprise,” “comprise,” or “have” are intended to designate the presence of implemented features, numbers, steps, components, or a combination thereof, and are intended to indicate the presence of one or more other features or It should be understood that this does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

According to one embodiment of the present invention,

As a method of manufacturing a p-type silicon carbide single crystal,

The concentration change rate ratio of silicon (Si) and aluminum (Al) satisfies condition 1 below,

[Condition 1]

In the above equation,

[Al] ₀ is the Al atom concentration in the initially added raw material mixture,

[Al] _t is the concentration of Al atoms among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,

[Si] ₀ is the concentration of Si atoms in the initially added raw material mixture,

[Si] _t is the concentration of Si atoms among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,

A method for manufacturing a p-type silicon carbide single crystal in which the concentration change rate of Si satisfies Condition 2 below is provided.

[Condition 2]

In the above equation,

[Si] ₀ and [Si] _t are as defined above,

t is growth time (h).

Specifically, the concentration change rate of Al compared to the concentration change rate of Si satisfies Condition 1 above.

In general, in the case of Al in the melt, the melting point is lower than that of Si and the vapor pressure is high, so when growth proceeds for a long time at high temperature, the concentration of Al in the melt decreases due to Al volatilization. Additionally, in the case of Si in the melt, it is consumed as a single crystal reactant, and the Si concentration in the solvent continues to decrease in proportion to the colon growth rate. Therefore, depending on the weight loss rate of Si and Al, the concentration of Al and Si in the melt changes.

However, if the concentration of Si is drastically reduced for rapid colon growth, polycrystals or intermetallic compounds are precipitated due to rapid changes in composition, or inclusions are incorporated, deteriorating the quality of the single crystal.

On the other hand, if the rate of decrease of the Si concentration in the solution due to crystal growth is less than the decrease rate of Al due to volatilization, the ratio of the Al concentration to the Si concentration in the melt, that is, [Al]/[Si], decreases. As the doping concentration of Al in the single crystal decreases and the single crystal grows, the specific resistance increases, making it difficult to obtain a p-type low-resistance single crystal. On the other hand, if the rate of decrease in Si concentration due to crystal growth is greater than the rate of decrease in Al concentration, [Al]/[Si] in the melt increases relatively, causing Al to be overdoped into SiC single crystals, or due to excessive growth of SiC. There is a problem that polycrystals, intermetallic compounds or inclusions are mixed, or the crystal growth rate is reduced.

Therefore, after repeated in-depth research by the inventors of the present application, the Al doping concentration is not simply a matter of the concentration of Al and Si, but the Al is doped into the lattice of Si, so they are in competition with each other. Since it is proportional to the ratio of the concentration of Al to Si in the melt, it was found that the resistivity ultimately changes depending on the concentration ratio of Si and Al depending on the growth direction of the single crystal. Therefore, in order to suppress the deviation of resistivity in the growth direction of a single crystal, it is very important to control the ratio of Si and Al concentration change rates over time to an appropriate range, rather than simply the concentration of Si and Al in the initially added raw material mixture. This was confirmed, and the most appropriate range was found.

In other words, when the concentration change rate ratio of Si and Al during crystal growth is maintained below 2 as in condition 1, there is an effect of reducing the deviation of resistivity in the direction of crystal growth.

Outside the above range, if it is 2 or more, the Al doping concentration in the SiC crystal decreases rapidly and the variation in resistivity is too large.

In detail, it is preferable that the concentration change rate ratio of Si and Al in Condition 1 above is 0.15 or more. As explained above, if the concentration of Si changes rapidly, there may be problems with inclusion mixing and polycrystals, so when it is within the above range, the quality of the single crystal can be further improved.

In addition, as explained above, when the concentration of Si changes rapidly, problems of polycrystalline or inclusion mixing occur, whereas when the concentration change rate of Si is too small, it is impossible to keep up with the volatilization rate of Al. Since the speed of crystal growth is too slow, it is desirable to control it appropriately, and accordingly, it is desirable to satisfy condition 2 above.

Outside the above range, if it is -1.3%/h or less, the reduction rate is too fast and inclusion mixing occurs as explained above, which is not desirable.

Meanwhile, in the method of manufacturing the p-type silicon carbide single crystal according to the present invention, a raw material mixture containing Si as a reactant, Al that substitutes for Si to make it p-type, and a metal (M) that increases carbon solubility is charged into a crucible. After forming a high-temperature Si-C melt, a SiC single crystal can be grown by supercooling the part where the seed crystal is immersed.

Specifically,

Preparing a silicon carbide seed crystal;

Preparing a raw material mixture by mixing silicon (Si) raw material, aluminum (Al) raw material, and metal (M) additive raw material other than Al;

Heating the raw material mixture in a crucible to form a melt containing carbon (C); and

A step of growing a silicon carbide single crystal by contacting the seed crystal with the melt,

Growth of the silicon carbide single crystal can be performed continuously.

In other words, the present invention can be effective by satisfying the above conditions by simply adjusting the manufacturing equipment used in the past without any additional measures such as changing the equipment or inserting an intermediate process.

Specifically, the inventors of the present application studied a method of controlling the concentration change rate ratio of Si and Al through in-depth research. Accordingly, the concentration decrease rate of Si in the melt is proportional to the SiC colon growth rate, so the temperature gradient It can be controlled by adjusting the concentration or carbon solubility, and since the rate of decrease in Al concentration is proportional to the volatilization rate of Al, it can be controlled by adjusting the crystal growth temperature, pressure, solvent, or interaction with metal additives. was confirmed.

Therefore, according to the production of each desired SiC single crystal, the above conditions of the present invention can be satisfied by adjusting the colon growth temperature, type, concentration, pressure, etc. of each metal additive as described above, which means that the above conditions are mutually exclusive. Since it has an influence, appropriate settings are required in each case and cannot be defined uniformly, and must be selected to satisfy conditions 1 and 2 above.

Below, the manufacturing method will be described in more detail.

In addition to the silicon (Si) raw material and aluminum (Al) raw material, metal (M) may be added, for example, one or more types selected from the group consisting of Cr, Cu, Ti, Mn, Co, V, and Fe. It may be an element, and in particular, may include chromium (Cr), which can improve carbon solubility.

The raw material mixtures are not limited, but may be in powder form.

The raw material mixture is heated in a crucible to form a melt, and at this time, the melt may further include carbon (C).

The carbon (C) may be supplied to the melt by using a graphite crucible, or the material of the crucible may be ceramics or a high melting point metal other than graphite. In this case, separate carbon is added to the crucible. (C) By adding raw materials, carbon (C) can be included in the melt, and the inner surface of the crucible can be supplied by coating it with a material made of graphite.

At this time, heating to form the melt may be performed in an inert atmosphere, and may be performed at a temperature at which the metals are melted, for example, 1700°C to 2200°C, until all of the metals are melted.

Additionally, the heating may be induction heating using a high-frequency heating coil.

As described above, a melt is formed by the heating. For example, when a graphite crucible is used, carbon is dissolved from the crucible into the melt, forming a melt containing carbon. Alternatively, when a graphite crucible is not used, carbon raw material may be further included in the raw material mixture, or graphite may be coated in the crucible to be dissolved.

By such heating, the carbon (C) in the melt approaches the saturation concentration, and then a seed crystal can be brought into contact with the melt to grow a silicon carbide single crystal.

Specifically, the growth of the silicon carbide single crystal is performed by adjusting the temperature of the melt to the crystal growth temperature and supercooling the area around the seed crystal by induction heating after the seed crystal is in contact with the melt.

At this time, the crystal growth temperature depends on the composition of the melt, but may be performed at, for example, 1600°C to 2000°C.

In addition, by making the temperature around the seed crystal lower than other parts by the supercooling, the SiC around the seed crystal is supersaturated, and the seed crystal and the crucible are rotated to generate a p-type SiC single crystal doped with Al on the surface of the seed crystal. , grow.

During this manufacturing process, as described above, according to the composition of the melt, the temperature gradient or carbon solubility, colon growth temperature, pressure, etc. can be adjusted to proceed with crystal growth to satisfy the above conditions according to the present invention. You can.

Therefore, the method for manufacturing a silicon carbide single crystal according to the present invention can be performed continuously, and can be achieved by finely controlling the process conditions within a range that is not significantly different from the conventional manufacturing method, without adding separate devices, processes, etc. You can.

Other basic manufacturing methods and manufacturing devices for silicon carbide single crystals are conventionally known, and detailed descriptions thereof are omitted in the present invention.

Meanwhile, according to the present invention, the aluminum (Al) concentration in the melt during the growth of the silicon carbide single crystal can be maintained within 1 to 15 at% among elements excluding carbon (C).

Outside the above range, as described above, if the Al concentration is too low, a p-type low-resistance single crystal cannot be obtained, and if the Al concentration is too high, inclusions are incorporated into the single crystal due to Al over-doping. This is not preferable because there is a problem that the crystal growth rate decreases.

Therefore, it is desirable to maintain the Al concentration within the above range, and according to the present invention, the Al concentration can also be maintained within the above range while satisfying the above conditions.

In the p-type silicon carbide single crystal manufactured by the manufacturing method according to the present invention, the ratio of the concentration change rate of Al to the concentration change rate of Si is maintained to satisfy the above condition 1 even if crystal growth is performed for a long period of time, and the doping concentration of Al is large. Since it does not change, the rate of change in resistivity along the growth direction is not large, so the quality can be maintained even if an ingot with a longer length in the growth direction is manufactured.

In detail, the p-type silicon carbide single crystal may be an ingot with a length in the growth direction of 3 mm or more, and the resistivity change rate may satisfy Equation 1 below.

[Equation 1]

Here, the resistivity is determined by removing the seed crystal and processing a specimen of 300㎛ each cut at 300㎛ based on the starting and ending points of the grown single crystal into a square of 5mm x 5mm, and then measuring 0.5 mm in diameter at the four corners of the Si surface. A specimen formed by soldering mm of In _0.95 Sn _0.05 alloy to form an ohmic contact was mounted on a Hall effect measuring device (Accent HL5500) at room temperature (25°C) and measured by van der Po ( It was measured using the Van-der Pauw method.

In other words, according to the manufacturing method of the present invention, an ingot with a length in the growth direction of 3 mm or more, a resistivity change rate that satisfies Equation 1 above, and a low-resistance p-type single crystal with a resistivity of 100 mΩ·cm or less can be grown.

The resistivity measurement method is as described above.

Hereinafter, the present invention will be further described in detail through examples. However, the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited to these only.

<Example 1>

56 at%, 40 at%, and 4 at% of solid Si, Cr, and Al, respectively, are added into the graphite crucible, and after evacuating, they are replaced with 0.39 MPa He. Afterwards, it is heated to 1900°C through induction heating to form a Si-Cr-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with the C-plane facing downward, with a thickness of 350 μm and a diameter of 15 mm, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. Afterwards, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was performed for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 3.8 mm was obtained.

A photograph of the obtained single crystal ingot is shown in Figure 1 below.

<Example 2>

45 at%, 40 at%, 10 at%, and 5 at% of solid Si, Cr, Fe, and Al, respectively, are added into the graphite crucible, and after evacuating, it is replaced with 0.1 MPa He. Afterwards, it is heated to 1800°C through induction heating to form a Si-Cr-Fe-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with a thickness of 350 μm and a diameter of 15 mm, with the C-plane facing downward, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. Afterwards, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was continued for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 3.9 mm was obtained.

<Example 3>

50 at%, 44 at%, and 6 at% of solid Si, Cr, and Al, respectively, are added into the graphite crucible, and after evacuating, they are replaced with 0.1 MPa He. Afterwards, it is heated to 2000°C through induction heating to form a Si-Cr-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with a diameter of 350 μm and a thickness of 15 mm, with the C-plane facing downward, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. Afterwards, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was performed for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 4.5 mm was obtained.

<Comparative Example 1>

50 at%, 40 at%, and 10 at% of solid Si, Cr, and Al, respectively, are put into the graphite crucible, and after evacuating, they are replaced with 0.1 MPa He. Afterwards, it is heated to 2100°C through induction heating to form a Si-Cr-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with the C-plane facing downward, with a thickness of 350 μm and a diameter of 15 mm, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. Afterwards, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was performed for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 4.1 mm was obtained.

<Comparative Example 2>

67 at%, 30 at%, and 3 at% of solid Si, Y, and Al, respectively, are put into the graphite crucible, and after evacuating, they are replaced with 0.1 MPa He. Afterwards, it is heated to 1800°C through induction heating to form a Si-Y-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with the C-plane facing downward, with a thickness of 350 μm and a diameter of 15 mm, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. Afterwards, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was performed for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 3.3 mm was obtained.

<Comparative Example 3>

57 at%, 20 at%, 20 at%, and 3 at% of solid Si, Cr, V, and Al, respectively, are added into the graphite crucible, and after evacuation, it is replaced with 0.1 MPa He. Afterwards, it is heated to 1900°C through induction heating to form a Si-Cr-V-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with the C-plane facing downward, with a thickness of 350 μm and a diameter of 15 mm, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. Afterwards, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was performed for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 3.6 mm was obtained.

<Comparative Example 4>

56 at%, 40 at%, and 4 at% of solid Si, Cr, and Al, respectively, are added into the graphite crucible, and after evacuating, they are replaced with 0.1 MPa He. Afterwards, it is heated to 2100°C through induction heating to form a Si-Cr-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with the C-plane facing downward, with a thickness of 350 μm and a diameter of 15 mm, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. Afterwards, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was performed for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 4.9 mm was obtained.

<Comparative Example 5>

50 at%, 40 at%, 5 at%, and 5 at% of solid Si, Cr, Fe, and Al, respectively, are added into the graphite crucible, and after evacuating, it is replaced with 0.1 MPa He. Afterwards, it is heated to 2100°C through induction heating to form a Si-Cr-Fe-Al solution, and the temperature is maintained for 30 minutes to bring the carbon concentration in the solution close to saturation.

Meanwhile, a 4H-SiC seed crystal with the C-plane facing downward, with a thickness of 350 μm and a diameter of 15 mm, is attached to the seed crystal holding axis of graphite, and the crystal growth surface is brought into contact with the melt. After that, a temperature gradient was created where the temperature decreased toward the top, and crystal growth was performed for 30 hours. After growth was completed, the seed crystal axis was raised to separate the melt surface from the seed crystal, and cooled to room temperature to recover the single crystal including the seed crystal. As a result, a SiC single crystal ingot with a total length of 5.4 mm was obtained.

<Experimental example>

In the manufacturing methods of Examples 1 to 3 and Comparative Examples 1 to 5, the solution composition after the process, the Si concentration change rate, the Al concentration change rate, the resistivity at the start of growth of the single crystal, and the resistivity at the end of growth were measured by the following methods and the results were obtained. is shown in Table 1 below.

*Post-process solution composition: After growth was completed, the solidified material remaining in the crucible was pulverized using a planetary mill (Retsch, PM100), and the composition of the remaining metal was quantitatively analyzed using XRF. Specifically, a calibration curve for each element was created using a standard sample with known concentration, and then the composition of the residual metal sample was quantitatively analyzed.

*Si concentration change rate: Calculated using the formula under Condition 2 below.

[Condition 2]

[Si] ₀ and [Si] _t are as defined in claim 1,

t is growth time (h).

*Al concentration change rate: Calculated using the formula under Condition 3 below.

[Condition 3]

In the above formula, [Al] ₀ and [Al] _t are as defined in clause 1 above,

t is growth time (h).

*Resistivity: After removing the seed crystal and processing the specimen by cutting 300㎛ each based on the start and end points of the grown single crystal into a square of 5mm x 5mm, In is placed at the four corners of the Si surface with a diameter of 0.5 mm. A specimen formed by soldering _0.95 Sn _0.05 alloy to form an ohmic contact was mounted on a Hall effect measuring device (Accent HL5500) at room temperature (25°C) and measured by Van der Po. It was measured using the Pauw method.

<Table 1>

Referring to Table 1, according to the present invention, as conditions 1 and 2 are satisfied, the resistivity change rate at the start and end point is 10%/mm or less, whereas in the case of Comparative Examples 1 to 3 that do not satisfy condition 1, the resistivity change rate It can be seen that this is very large, and in the case of Comparative Examples 4 to 5, which did not satisfy Condition 2, a large amount of inclusions and polycrystals were contained, making specific resistance measurement impossible.

Although specific embodiments of the present invention have been described and shown above, it is known in the art that the present invention is not limited to the described embodiments, and that various modifications and changes can be made without departing from the spirit and scope of the present invention. This is self-evident to those who have it. Accordingly, such modifications or variations should not be understood individually from the technical idea or viewpoint of the present invention, and the modified embodiments should be considered to fall within the scope of the claims of the present invention.

Claims (10)

As a method of manufacturing a p-type silicon carbide single crystal,
The concentration change rate ratio of silicon (Si) and aluminum (Al) satisfies condition 1 below,
[Condition 1]

In the above equation,
[Al] ₀ is the Al atom concentration in the initially added raw material mixture,
[Al] _t is the concentration of Al atoms among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,
[Si] ₀ is the concentration of Si atoms in the initially added raw material mixture,
[Si] _t is the concentration of Si atoms among elements other than carbon (C) in the melt after completion of silicon carbide single crystal growth,
Method for manufacturing p-type silicon carbide single crystal where the concentration change rate of Si satisfies condition 2 below:
[Condition 2]

In the above equation,
[Si] ₀ and [Si] _t are as defined above,
t is growth time (h). The method of claim 1, wherein the method of manufacturing the p-type silicon carbide single crystal comprises:
Preparing a silicon carbide seed crystal;
Preparing a raw material mixture by mixing silicon (Si) raw material, aluminum (Al) raw material, and metal (M) additive raw material other than Al;
Heating the raw material mixture in a crucible to form a melt containing carbon (C); and
A step of growing a silicon carbide single crystal by contacting the seed crystal with the melt,
A method for manufacturing a p-type silicon carbide single crystal, wherein the growth of the silicon carbide single crystal is performed continuously. The method of claim 2, wherein the metal (M) is at least one element selected from the group consisting of Cr, Cu, Ti, Mn, Co, V, and Fe. The method of claim 2, wherein the method of forming the melt containing carbon uses a graphite crucible or adds a separate carbon (C) raw material. The method of claim 2, wherein heating to form the melt is performed at 1700°C to 2200°C. The method of claim 2, wherein the growth of the silicon carbide single crystal is performed at 1600°C to 2000°C. The method of claim 2, wherein the aluminum concentration in the melt during growth of the silicon carbide single crystal is maintained within 1 to 15 at% of elements other than carbon (C). The method of claim 1, wherein the p-type silicon carbide single crystal is an ingot with a length in the growth direction of 3 mm or more. The method of manufacturing a p-type silicon carbide single crystal according to claim 1, wherein the rate of change in resistivity of the grown silicon carbide single crystal satisfies the following equation 1:
[Equation 1]
delete