P-type crystal, liquid phase growth device and liquid phase growth method

Abstract

The invention belongs to the technical field of crystal growth, and particularly relates to a P-type crystal, a liquid phase growth device and a liquid phase growth method. The P-type crystal comprises silicon carbide, the Al element doping concentration is larger than or equal to 5E19 cm <-3 >, the N element doping concentration is smaller than or equal to 1E19 cm <-3 >, the doping non-uniformity of the P-type crystal in the radial direction and the axial direction is smaller than 10%, and the resistivity is smaller than or equal to 0.1 omega.cm. The baffle is arranged in the liquid phase growth device, the evaporation space is reduced, effective internal circulation is achieved in the crucible, the outer water cooling shaft is arranged to provide the temperature gradient, evaporation is effectively inhibited, meanwhile, growth speed reduction caused by evaporation inhibition is avoided, and growth crystal doping and uniform distribution of resistivity are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of crystal growth, and in particular relates to a P-type crystal and a liquid phase growth device and a liquid phase growth method. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Compared with the physical vapor transport method, the liquid phase method has a low growth temperature, a growth process close to thermodynamic equilibrium conditions, low crystal defect density, good crystal quality, low growth cost, and easier P-type doping, which has good application prospects. However, when preparing crystals (such as silicon carbide) based on the liquid phase method, the volatile components in the raw materials will move upward and even evaporate into gas and continue to overflow to the external insulation components, causing a series of problems that affect the growth and quality of the crystals:

[0004] Evaporation will increase the concentration of solutes in the solution, change the saturation of the solution, increase the supersaturation of the solution, and may cause the solute to precipitate on the container wall or other surfaces instead of on the crystals, thus producing miscellaneous crystals;

[0005] During the evaporation process, different components may have different evaporation rates, resulting in non-uniformity of solution composition and causing the solution to deviate from the optimal growth state;

[0006] Changes in the solution evaporation rate may cause fluctuations in the crystal growth rate, which may cause the growth conditions on the crystal surface to constantly change, thereby affecting the uniformity and quality of the crystal. The resulting P-type crystal is difficult to ensure uniformity in doping and resistivity.

[0007] To solve the above problems, it is usually necessary to take measures to control evaporation during the liquid phase growth process, such as monitoring the solution height and replenishing the solution to compensate for the evaporation damage, or using the liquid seal method, lowering the growth temperature to reduce the evaporation rate, reducing the gap between the upper insulation and the seed crystal axis to reduce the gas flow channel and other methods to inhibit evaporation. However, the steps of monitoring the solution height and replenishing the solution are cumbersome, and the crystal growth rate changes with the solution height, which is not conducive to the stable growth of the crystal; the liquid seal method has a narrow scope of application and is not suitable for crystals such as silicon carbide; lowering the growth temperature will lead to a decrease in the growth rate, and reducing the gas flow channel will lead to too small a temperature gradient in the solution, low supersaturation and thus a decrease in the growth rate. Therefore, although the existing methods suppress the problems caused by evaporation, they are achieved at the cost of reducing the growth rate. Summary of the invention

[0008] In order to solve the deficiencies of the prior art, the present invention provides a P-type crystal and a liquid phase growth device and a liquid phase growth method. The present invention sets a baffle in the liquid phase growth device to reduce the evaporation space, achieve effective internal circulation inside the crucible, and sets an external water-cooled shaft to provide a temperature gradient, effectively suppressing evaporation while avoiding the reduction in growth rate caused by suppressing evaporation, and achieving uniform distribution of doping and resistivity of the growing crystal.

[0009] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0010] In a first aspect, the present invention provides a P-type crystal, wherein the P-type crystal comprises silicon carbide, and the Al element doping concentration is ≥5E19 cm -3 , N element doping concentration ≤ 1E19 cm -3 The P-type crystal has a doping non-uniformity of less than 10% in radial and axial directions, and a resistivity of less than or equal to 0.1Ω·cm.

[0011] Preferably, the half-width of the LOPC mode of the Raman spectrum varies in the range of 0 to 3 cm -1 .

[0012] Preferably, the Al doping concentration in the P-type crystal is ≥1E20 cm -3 .

[0013] Preferably, the silicon carbide includes 4H-SiC, 6H-SiC or 3C-SiC.

[0014] Preferably, the resistivity is ≤0.05Ω·cm.

[0015] Preferably, the doping non-uniformity of the P-type crystal in radial and axial directions is less than 1%.

[0016] In a second aspect, the present invention provides a liquid phase growth device for growing the P-type crystal as described in the first aspect, comprising:

[0017] A crucible, wherein a heat-insulating material is arranged outside the crucible, and the crucible is arranged on a crucible supporting shaft;

[0018] A heating coil, wherein the heating coil is arranged outside the heat-insulating material;

[0019] A seed crystal shaft, one end of which is provided with a seed crystal holder, and the seed crystal shaft is connected to an inner water-cooled shaft;

[0020] An external water-cooling shaft, which is arranged outside the internal water-cooling shaft and is lifted and rotated independently of the internal water-cooling shaft;

[0021] A baffle is provided with holes for the seed crystal shaft and the inner water-cooling shaft to pass through, and the baffle is connected to one end of the outer water-cooling shaft.

[0022] Preferably, the baffle comprises a graphite plate, a coated graphite plate or a heat-resistant metal plate.

[0023] Further preferably, the material of the coating includes tantalum carbide or boron nitride, and the heat-resistant metal includes at least one of tungsten, iridium, platinum and rhodium.

[0024] Preferably, the outer water-cooling shaft and the inner water-cooling shaft are arranged concentrically, and the ratio of the inner diameter of the outer water-cooling shaft to the outer diameter of the inner water-cooling shaft is (1.05-1.1):1.

[0025] Preferably, the baffle is an annular baffle, the inner diameter of the baffle is equal to the inner diameter of the external water-cooled shaft, and the ratio of the outer diameter of the baffle to the inner diameter of the crucible is (0.95-0.99):1.

[0026] In a third aspect, the present invention provides a liquid phase growth method, using the liquid phase growth device as described in the second aspect, comprising the following steps:

[0027] Connect the seed crystal to the seed crystal axis and place the raw material in the crucible, move the seed crystal axis to the initial position and move the baffle to be flush with the seed crystal, evacuate the liquid phase growth device and introduce inert gas;

[0028] Heating the raw materials to melt and form a solution, further heating to a predetermined growth temperature, lowering the seed crystal axis until the seed crystal contacts the solution surface, lowering the baffle to above the solution surface, and growing the crystal according to the set process and time;

[0029] After the crystal growth is completed, the baffle is lifted to the initial position, the seed crystal axis is pulled until the crystal is separated from the solution, the temperature of the crystal growth chamber is lowered to room temperature, and the crystal is taken out.

[0030] Preferably, it is characterized in that the baffle is lowered to 5 to 10 mm above the liquid surface of the solution.

[0031] The beneficial effects achieved by one or more technical solutions of the present invention are as follows:

[0032] The P-type crystal obtained by the present invention has greatly reduced axial and radial doping non-uniformity, achieving uniform resistivity distribution, and the high doping concentration in the P-type crystal reduces the resistivity while achieving uniform distribution. The P-type crystal of the present invention has excellent electrical properties, ensuring the optimization of switching speed, power consumption and overall performance of semiconductor devices prepared using the P-type crystal as raw material.

[0033] The present invention provides a baffle in the liquid phase growth device, covers the solution surface by the baffle, forms internal and external spaces inside the crucible, reduces the evaporation space, achieves effective internal circulation inside the crucible, and provides an external water-cooling shaft to provide a temperature gradient, effectively avoiding a reduction in growth rate due to evaporation inhibition.

[0034] The liquid phase growth method provided by the present invention can suppress the adverse effect of evaporation on crystal growth by regulating the position of an external water-cooled shaft and a baffle. The external water-cooled shaft and the baffle do not affect the parameter setting of crystal growth, and can be applied to the liquid phase growth of P-type crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0036] Figure 1 It is a schematic structural diagram of the liquid phase growth device of the present invention;

[0037] Figure 2 A schematic diagram of the structure of the crystal growth process in an embodiment of the present invention;

[0038] In the figure, 1 is a crucible, 2 is a heat-insulating material, 3 is a crucible supporting shaft, 4 is a heating coil, 5 is a seed crystal shaft, 6 is an inner water-cooled shaft, 7 is an outer water-cooled shaft, 8 is a baffle, 9 is a seed crystal, and 10 is a solution. DETAILED DESCRIPTION

[0039] As described in the background technology, in the existing methods for suppressing evaporation, the steps of monitoring the solution height and replenishing the solution are cumbersome, and the crystal growth rate changes with the solution height, which is not conducive to the stable growth of the crystal; the liquid sealing method has a narrow scope of application and is not suitable for crystals such as silicon carbide; lowering the growth temperature and reducing the gap between the upper insulation and the seed crystal axis will lead to too small a temperature gradient in the solution, low supersaturation, and thus a reduced growth rate. Although the existing methods suppress the problems caused by evaporation, they are achieved at the cost of reducing the growth rate.

[0040] In order to solve the above problems, the present invention provides a P-type crystal, a liquid phase growth device and a liquid phase growth method.

[0041] In an embodiment of the present invention, a P-type crystal is provided, wherein the P-type crystal comprises silicon carbide, and the Al element doping concentration is ≥ 5E19 cm -3 , N element doping concentration ≤ 1E19 cm -3 The P-type crystal has a doping non-uniformity of less than 10% in radial and axial directions, and a resistivity of less than or equal to 0.1Ω·cm.

[0042] In the embodiment of the present invention, the half-width of the LOPC mode of the Raman spectrum varies in the range of 0 to 3 cm -1 .

[0043] In the embodiment of the present invention, the Al doping concentration in the P-type crystal is ≥1E20 cm -3 .

[0044] In an embodiment of the present invention, the silicon carbide includes 4H-SiC, 6H-SiC or 3C-SiC.

[0045] Preferably, the resistivity is ≤0.05Ω·cm.

[0046] Preferably, the doping non-uniformity of the P-type crystal in radial and axial directions is less than 1%.

[0047] In an embodiment of the present invention, a liquid phase growth device is provided for growing the P-type crystal as described above, comprising:

[0048] A crucible, wherein a heat-insulating material is arranged outside the crucible, and the crucible is arranged on a crucible supporting shaft;

[0049] A heating coil, wherein the heating coil is arranged outside the heat-insulating material;

[0050] A seed crystal shaft, one end of which is provided with a seed crystal holder, and the seed crystal shaft is connected to an inner water-cooled shaft;

[0051] An external water-cooling shaft, which is arranged outside the internal water-cooling shaft and is lifted and rotated independently of the internal water-cooling shaft;

[0052] A baffle is provided with holes for the seed crystal shaft and the inner water-cooling shaft to pass through, and the baffle is connected to one end of the outer water-cooling shaft.

[0053] Since the evaporation of the solution, co-solvent, and dopant during the crystal growth process will reduce the quality and growth rate of the crystal growth, the present invention sets a baffle in the liquid phase growth device, and uses the baffle to cover the liquid surface of the solution, forming an internal and external space inside the crucible, so that the evaporation space is reduced, and an effective internal circulation is achieved inside the crucible. However, the single setting of the baffle will cause the temperature gradient to be reduced while suppressing evaporation. Therefore, the liquid phase growth device of the present invention is further provided with an external water-cooled shaft. On the one hand, the external water-cooled shaft can be independently raised and lowered and rotated and connected to the baffle to drive the baffle to move, and on the other hand, it provides additional supercooling for the seed crystal shaft and forms a temperature gradient. By setting a baffle and an external water-cooled shaft, the present invention utilizes the synergistic effect of the two to suppress the evaporation of the solution without affecting the crystal growth rate.

[0054] In an embodiment of the present invention, the baffle comprises a graphite plate, a coated graphite plate or a heat-resistant metal plate.

[0055] In an embodiment of the present invention, the material of the coating layer includes tantalum carbide or boron nitride, and the heat-resistant metal includes at least one of tungsten, iridium, platinum and rhodium.

[0056] In an embodiment of the present invention, the outer water-cooling shaft is concentrically arranged with the inner water-cooling shaft, and the ratio of the inner diameter of the outer water-cooling shaft to the outer diameter of the inner water-cooling shaft is (1.05-1.1):1.

[0057] The inner diameter of the outer water-cooled shaft is different from the outer diameter of the inner water-cooled shaft. The gap between the two facilitates the movement of the seed crystal driven by the seed crystal shaft and provides a gas flow channel, which is conducive to the formation of a temperature gradient.

[0058] In an embodiment of the present invention, the baffle is an annular baffle, the inner diameter of the baffle is equal to the inner diameter of the external water-cooled shaft, and the ratio of the outer diameter of the baffle to the inner diameter of the crucible is (0.95-0.99):1.

[0059] The crucible needs to rotate during the liquid phase crystal growth process, so the outer diameter of the baffle is set to ensure the suppression effect on the vapor without affecting the rotation of the crucible.

[0060] In an embodiment of the present invention, a liquid phase growth method is provided, using the liquid phase growth device as described above, comprising the following steps:

[0061] Connect the seed crystal to the seed crystal axis and place the raw material in the crucible, move the seed crystal axis to the initial position and move the baffle to be flush with the seed crystal, evacuate the liquid phase growth device and introduce inert gas;

[0062] Heating the raw materials to melt and form a solution, further heating to a predetermined growth temperature, lowering the seed crystal axis until the seed crystal contacts the solution surface, lowering the baffle to above the solution surface, and growing the crystal according to the set process and time;

[0063] After the crystal growth is completed, the baffle is lifted to the initial position, the seed crystal axis is pulled until the crystal is separated from the solution, the temperature of the crystal growth chamber is lowered to room temperature, and the crystal is taken out.

[0064] Compared with the existing crystal growth methods, the liquid phase growth method provided by the present invention can suppress the adverse effects of evaporation on crystal growth by regulating the positions of the external water-cooling shaft and the baffle. The external water-cooling shaft and the baffle do not affect the parameter setting of crystal growth, and the existing technology can be used.

[0065] In the embodiment of the present invention, it is characterized in that the baffle is lowered to 5 to 10 mm above the liquid surface of the solution.

[0066] By utilizing the liquid phase growth device and liquid phase growth method of the present invention, the changes in solution components, solution composition inhomogeneity and crystal growth rate caused by evaporation can be effectively suppressed, thereby ensuring the stability and consistency of the crystal growth process. As a result, the axial and radial doping inhomogeneity of the obtained crystal is greatly reduced, achieving a uniform resistivity distribution.

[0067] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in combination with specific embodiments and comparative examples.

[0068] Example 1

[0069] like Figure 1 As shown, the liquid phase growth device comprises:

[0070] Crucible 1, a heat-insulating material 2 is arranged outside the crucible 1, and the crucible 1 is arranged on a crucible support 3 axis;

[0071] A heating coil 4, which is arranged outside the heat-insulating material 2;

[0072] A seed crystal shaft 5, which is connected to an inner water-cooled shaft 6;

[0073] An external water-cooling shaft 7, which is arranged outside the internal water-cooling shaft 6, and is lifted and rotated independently of the internal water-cooling shaft 6;

[0074] The baffle plate 8 is provided with holes for the seed crystal shaft 5 and the inner water-cooling shaft 6 to pass through, and the baffle plate 9 is connected to one end of the outer water-cooling shaft 8 .

[0075] The liquid phase growth method using the liquid phase growth device comprises the following steps:

[0076] Connect the seed crystal 9 to the seed crystal shaft 6 and place the raw material in the crucible 1, move the seed crystal shaft 5 to the initial position and move the baffle 9 to be flush with the seed crystal, evacuate the liquid phase growth device and introduce inert gas;

[0077] The raw material is heated to melt to form a solution 10, and the temperature is further raised to a predetermined growth temperature, the seed crystal shaft 5 is lowered until the seed crystal 9 contacts the liquid surface of the solution 10, and the baffle 8 is lowered to above the liquid surface of the solution 10. Figure 2 As shown, the crystal growth is carried out according to the set process and time;

[0078] After the crystal growth is completed, the baffle 8 is lifted to the initial position, the seed crystal axis 5 is pulled until the crystal is separated from the solution 10, the temperature of the crystal growth chamber is lowered to room temperature, and the crystal is taken out.

[0079] Example 2

[0080] The liquid phase growth apparatus in Example 1 is used to grow Al-doped P-type silicon carbide in the following steps:

[0081] Connect the seed crystal 9 (4H-SiC) to the seed crystal shaft 6 and place the raw materials (mass ratio Si:Cr:Al=70:20:10) in the crucible 1 (made of graphite), move the seed crystal shaft 5 to the initial position and move the baffle 8 to be flush with the seed crystal 9, evacuate the liquid phase growth device and introduce inert gas;

[0082] The raw material is heated to melt to form a solution 10, and the temperature is further raised to a predetermined growth temperature, the seed crystal shaft 5 is lowered until the seed crystal 9 contacts the liquid surface of the solution 10, the baffle 8 is lowered to 10 mm above the liquid surface of the solution 10, and the silicon carbide crystal is grown according to the set process and time;

[0083] After the growth of the silicon carbide crystal is completed, the baffle 8 is lifted to the initial position, the seed crystal axis 5 is pulled until the crystal is separated from the solution 10, the temperature of the crystal growth chamber is lowered to room temperature, and the silicon carbide crystal is taken out.

[0084] The obtained SiC crystal is P-type conductive, with Al doping concentration ≥1E20 cm -3 , element doping concentration ≤ 1E19 cm -3 , resistivity ≤ 0.05Ω·cm, radial and axial doping inhomogeneity < 1%, the half-width of the LOPC mode of the Raman spectrum varies in the range of 0 to 3cm -1 .

[0085] Example 3

[0086] like Figure 1 As shown, the liquid phase growth device comprises:

[0087] Crucible 1, a heat-insulating material 2 is arranged outside the crucible 1, and the crucible 1 is arranged on a crucible support 3 axis;

[0088] A heating coil 4, which is arranged outside the heat-insulating material 2;

[0089] A seed crystal shaft 5, which is connected to an inner water-cooled shaft 6;

[0090] The outer water-cooling shaft 7 is concentrically arranged outside the inner water-cooling shaft 6, the ratio of the inner diameter of the outer water-cooling shaft 7 to the outer diameter of the inner water-cooling shaft 6 is 1.05:1, and the outer water-cooling shaft 7 is lifted and rotated independently of the inner water-cooling shaft 6;

[0091] The baffle 8 is an annular baffle, the inner diameter of the baffle 8 is equal to the inner diameter of the outer water-cooled shaft 7, the ratio of the outer diameter of the baffle 8 to the inner diameter of the crucible 1 is 0.99:1, the hole of the baffle 8 is for the seed crystal shaft 5 and the inner water-cooled shaft 6 to pass through, and the baffle 9 is connected to one end of the outer water-cooled shaft 8.

[0092] Example 4

[0093] like Figure 1 As shown, the liquid phase growth device comprises:

[0094] Crucible 1, a heat-insulating material 2 is arranged outside the crucible 1, and the crucible 1 is arranged on a crucible support 3 axis;

[0095] A heating coil 4, which is arranged outside the heat-insulating material 2;

[0096] A seed crystal shaft 5, which is connected to an inner water-cooled shaft 6;

[0097] The outer water-cooling shaft 7 is concentrically arranged outside the inner water-cooling shaft 6, the ratio of the inner diameter of the outer water-cooling shaft 7 to the outer diameter of the inner water-cooling shaft 6 is 1.1:1, and the outer water-cooling shaft 7 is lifted and rotated independently of the inner water-cooling shaft 6;

[0098] The baffle 8 is an annular baffle, the inner diameter of the baffle 8 is equal to the inner diameter of the outer water-cooled shaft 7, the ratio of the outer diameter of the baffle 8 to the inner diameter of the crucible 1 is 0.95:1, the hole of the baffle 8 is for the seed crystal shaft 5 and the inner water-cooled shaft 6 to pass through, and the baffle 9 is connected to one end of the outer water-cooled shaft 8.

[0099] Comparative Example 1

[0100] A crystal growth apparatus, comprising:

[0101] Crucible 1, a heat-insulating material 2 is arranged outside the crucible 1, and the crucible 1 is arranged on a crucible support 3 axis;

[0102] A heating coil 4, which is arranged outside the heat-insulating material 2;

[0103] The seed crystal shaft 5 is connected to the inner water-cooling shaft 6 .

[0104] The crystal growth method using the crystal growth device comprises the following steps:

[0105] Connect the seed crystal 9 to the seed crystal shaft 6 and place the raw material in the crucible 1, move the seed crystal shaft 5 to the initial position, evacuate the crystal growth device and introduce inert gas;

[0106] The raw material is heated to melt to form a solution 10, and the temperature is further raised to a predetermined growth temperature, and the seed crystal axis 5 is lowered until the seed crystal 9 contacts the liquid surface of the solution 10, and the crystal is grown according to the set process and time;

[0107] After the crystal growth is completed, the seed crystal axis 5 is pulled up until the crystal is separated from the solution 10, the temperature of the crystal growth chamber is lowered to room temperature, and the crystal is taken out.

[0108] Comparative Example 2

[0109] The crystal growth apparatus in Comparative Example 1 is used to grow Al-doped P-type silicon carbide in the following steps:

[0110] Connect the 4H-SiC seed crystal to the seed crystal shaft 6 and place the raw materials (mass ratio Si:Cr:Al=70:20:10) in the crucible 1 (made of graphite), move the seed crystal shaft 5 to the initial position, evacuate the crystal growth device and introduce inert gas;

[0111] The raw material is heated to melt to form a solution 10, and the temperature is further raised to a predetermined growth temperature, and the seed crystal shaft 5 is lowered until the seed crystal 9 contacts the liquid surface of the solution 10, and the silicon carbide crystal is grown according to the set process and time;

[0112] After the growth of the silicon carbide crystal is completed, the seed crystal axis 5 is pulled up until the crystal is separated from the solution 10, the temperature of the crystal growth chamber is lowered to room temperature, and the silicon carbide crystal is taken out.

[0113] The obtained SiC crystal is P-type conductive, and the Al doping concentration is less than 1E20 cm -3 , resistivity>0.1Ω·cm, and doping non-uniformity in radial and axial directions>10%.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A P-type crystal, characterized in that: The P-type crystal comprises silicon carbide, and the Al element doping concentration is ≥5E19 cm -3 , N element doping concentration ≤ 1E19 cm -3 The doping non-uniformity of the P-type crystal in radial and axial directions is less than 10%, and the resistivity is ≤0.1Ω·cm.

2. The crystal according to claim 1, characterized in that The half-width of the LOPC mode of the Raman spectrum varies from 0 to 3 cm -1 .

3. The crystal according to claim 1, characterized in that The Al doping concentration of the P-type crystal is ≥1E20 cm -3 , resistivity ≤ 0.05Ω·cm, and the doping non-uniformity of P-type crystal in radial and axial directions is less than 1%.

4. The crystal according to claim 1, characterized in that The silicon carbide includes 4H-SiC, 6H-SiC or 3C-SiC.

5. A liquid phase growth device, characterized in that: For growing the P-type crystal according to any one of claims 1 to 4, comprising: A crucible, wherein a heat-insulating material is arranged outside the crucible, and the crucible is arranged on a crucible supporting shaft; A heating coil, wherein the heating coil is arranged outside the heat-insulating material; A seed crystal shaft connected to an inner water-cooled shaft; An external water-cooling shaft, which is arranged outside the internal water-cooling shaft and is lifted and rotated independently of the internal water-cooling shaft; A baffle is provided with holes for the seed crystal shaft and the inner water-cooling shaft to pass through, and the baffle is connected to one end of the outer water-cooling shaft.

6. The liquid phase growth device according to claim 5, characterized in that: The baffle plate includes a graphite plate, a coated graphite plate or a heat-resistant metal plate.

7. The liquid phase growth device according to claim 6, characterized in that: The material of the coating layer includes tantalum carbide or boron nitride, and the heat-resistant metal includes at least one of tungsten, iridium, platinum and rhodium.

8. The liquid phase growth device according to claim 4, characterized in that: The outer water-cooling shaft is concentrically arranged with the inner water-cooling shaft, and the ratio of the inner diameter of the outer water-cooling shaft to the outer diameter of the inner water-cooling shaft is (1.05-1.1):1; The baffle is an annular baffle, the inner diameter of the baffle is equal to the inner diameter of the external water-cooled shaft, and the ratio of the outer diameter of the baffle to the inner diameter of the crucible is (0.95-0.99):

1.

9. A liquid phase growth method, characterized in that: Using the liquid phase growth device as described in any one of claims 5 to 8 comprises the following steps: Connect the seed crystal to the seed crystal shaft and place the raw material in the crucible, move the seed crystal shaft to the initial position and move the baffle to be flush with the seed crystal, evacuate the crystal growth device and introduce inert gas; Heating the raw materials to melt and form a solution, further heating to a predetermined growth temperature, lowering the seed crystal axis until the seed crystal contacts the solution surface, lowering the baffle to above the solution surface, and growing the crystal according to the set process and time; After the crystal growth is completed, the baffle is lifted to the initial position, the seed crystal axis is pulled until the crystal is separated from the solution, the temperature of the crystal growth chamber is lowered to room temperature, and the crystal is taken out.

10. The liquid phase growth method according to claim 9, characterized in that: Lower the baffle to 5 to 10 mm above the solution surface.

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