Crucible for crystal growth and crystal growth equipment

Abstract

The embodiment of the utility model provides a crucible for crystal growth and crystal growth equipment. On any section perpendicular to the axis of the crucible, the wall thickness of the crucible comprises a first wall thickness value and a second wall thickness value, the first wall thickness value is the maximum value of the wall thickness of the crucible, the second wall thickness value is the minimum value of the wall thickness of the crucible, and the first wall thickness value is different from the second wall thickness value. The crystal growth equipment comprises a seed crystal support crucible, the shortest distance between a seed crystal support and the inner wall of the crucible is between a first distance and a second distance, the first distance is the maximum value of the shortest distance, and the second distance is the minimum value of the shortest distance; the first distance is different from the second distance.

Description

Technical Field

[0001] The present invention relates to the field of crystal growth, and in particular to a crucible and a crystal growth device for crystal growth. Background Art

[0002] Semiconductor crystals (e.g., silicon carbide single crystals) have excellent physical and chemical properties, and therefore have become important materials for manufacturing high-frequency and high-power devices. Common growth methods for semiconductor crystals may include physical vapor transmission method, liquid phase method, etc. The basic principle of the liquid phase method is: placing the raw materials and flux in a crucible, heating and melting the raw materials and flux to form a melt; then placing the seed crystal on the liquid surface of the melt, and the different substances in the raw materials combine to form a crystal.

[0003] It is desirable to provide a crucible for crystal growth and a crystal growth apparatus that can achieve higher efficiency and higher quality crystal growth. Utility Model Content

[0004] In order to solve the above problems, the present application provides a crucible and crystal growth equipment for crystal growth. By redesigning the structure of the crucible, the fluid flow field in the growth chamber during the crystal growth process can be adjusted to form a fast path, thereby ensuring smooth growth of the crystal, effectively reducing the impurity content and defects in the crystal, improving the growth efficiency of the crystal, and achieving more efficient and higher quality crystal growth.

[0005] One of the embodiments of the present specification provides a crucible for crystal growth, wherein on any cross section perpendicular to the axis of the crucible, the wall thickness of the crucible includes a first wall thickness value and a second wall thickness value, wherein the first wall thickness value is the maximum value of the wall thickness of the crucible, and the second wall thickness value is the minimum value of the wall thickness of the crucible, and the first wall thickness value is different from the second wall thickness value.

[0006] In some embodiments, the crucible wall position where the first wall thickness value is formed and the crucible wall position where the second wall thickness value is formed are located on opposite sides of the central axis of the inner wall of the crucible.

[0007] In some embodiments, the inner wall and the outer wall of the crucible are both cylindrical, and the inner wall is parallel to the central axis of the outer wall and is spaced apart from each other.

[0008] In some embodiments, the ratio of the first wall thickness value to the second wall thickness value is 1.5 to 20.0.

[0009] In some embodiments, the first wall thickness value ranges from 10 mm to 100 mm, and the second wall thickness value ranges from 10 mm to 30 mm.

[0010] One of the embodiments of the present specification provides a crystal growth device, which includes a seed crystal holder and a crucible, wherein the spacing distance between the seed crystal holder and the inner wall of the crucible includes a first distance and a second distance, wherein the first distance is the maximum value of the spacing distance and the second distance is the minimum value of the spacing distance; the first distance and the second distance are different.

[0011] In some embodiments, the position of the inner wall of the crucible forming the first distance and the position of the inner wall of the crucible forming the second distance are located on opposite sides of a central axis of the inner wall of the crucible.

[0012] In some embodiments, the ratio of the first distance to the second distance is 1.5 to 19.0; and / or the first distance ranges from 50 mm to 95 mm, and the second distance ranges from 5 mm to 50 mm.

[0013] In some embodiments, the crystal growth equipment also includes a furnace body, and the crucible and the seed crystal holder are located in the furnace body; the central axis of the outer wall of the crucible, the central axis of the furnace body and the central axis of the seed crystal holder coincide with each other, and the distance between the central axis of the inner wall of the crucible and the central axis of the furnace body is 5 mm to 45 mm.

[0014] This specification includes at least the following beneficial effects: by setting the side wall thickness of the crucible to be uneven, the temperature and flow velocity distribution around the seed crystal can be made asymmetrical, so as to control the temperature field and fluid flow field in the growth chamber during the crystal growth process when the seed crystal holder and the seed crystal rod rotate. When the seed crystal holder and the seed crystal rod rotate, the eddy current near the seed crystal holder and the seed crystal rod is affected, so that the eddy current on the thinner side of the crucible side wall is weaker, and the eddy current on the thicker side of the crucible side wall is stronger, thereby controlling the fluid flow field in the growth chamber during the crystal growth process, forming a fast path, ensuring the smooth growth of the crystal, effectively reducing the impurity content and defects in the crystal, improving the melting efficiency and the growth efficiency of the crystal, and achieving more efficient and higher quality crystal growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0016] Figure 1 is a schematic diagram of an XZ cross-section of a crucible according to some embodiments of the present specification;

[0017] Figure 2 is an XY cross-sectional schematic diagram of a crucible according to some embodiments of the present specification;

[0018] Figure 3is a schematic diagram of the structure of a crystal growth device according to some embodiments of this specification;

[0019] Figure 4 is a schematic diagram of an XZ cross-section of a crystal growth device according to some embodiments of the present specification;

[0020] Figure 5A is a schematic diagram of magnetic flux distribution in an XZ cross section of a crystal growth device corresponding to Embodiment 1 shown in some embodiments of this specification;

[0021] Figure 5B is a schematic diagram of magnetic flux distribution of a crucible in a crystal growth device corresponding to Embodiment 1 shown in some embodiments of this specification;

[0022] Figure 5C is a schematic diagram of magnetic flux distribution of a melt in a crucible of a crystal growth device corresponding to Embodiment 1 shown in some embodiments of this specification;

[0023] Figure 5D is a temperature distribution diagram of an XZ cross section of a crucible in a crystal growth device corresponding to Embodiment 1 shown in some embodiments of this specification;

[0024] Figure 5E is a temperature distribution diagram of an XZ cross section of a melt in a crucible of a crystal growth device corresponding to Embodiment 1 shown in some embodiments of this specification;

[0025] Fig. 5F is a streamline diagram of an XZ cross section of a melt in a crucible in a crystal growth device corresponding to Embodiment 1 shown in some embodiments of this specification;

[0026] Fig. 6A is a schematic diagram of magnetic flux distribution in an XZ cross section of a crystal growth device corresponding to Embodiment 4 shown in some embodiments of this specification;

[0027] Figure 6B is a schematic diagram of magnetic flux distribution of a crucible in a crystal growth device corresponding to Embodiment 4 shown in some embodiments of this specification;

[0028] Figure 6C is a schematic diagram of magnetic flux distribution of a melt in a crucible of a crystal growth device corresponding to Embodiment 4 shown in some embodiments of this specification;

[0029] Fig.6D is a temperature distribution diagram of an XZ cross section of a crucible in a crystal growth device corresponding to Embodiment 4 shown in some embodiments of this specification;

[0030] Fig. 6Eis a temperature distribution diagram of an XZ cross section of a melt in a crucible in a crystal growth device corresponding to Example 4 shown in some embodiments of this specification;

[0031] Fig. 6F is a streamline diagram of an XZ cross section of a melt in a crucible in a crystal growth device corresponding to Example 4 shown in some embodiments of this specification;

[0032] Fig. 7A is a schematic diagram of magnetic flux distribution in an XZ cross section of a crystal growth device corresponding to Embodiment 7 shown in some embodiments of this specification;

[0033] Figure 7B is a schematic diagram of magnetic flux distribution of a melt in a crucible of a crystal growth device corresponding to Embodiment 7 shown in some embodiments of this specification;

[0034] Figure 7C is a temperature distribution diagram of an XZ cross section of a crystal growth device corresponding to Embodiment 7 shown in some embodiments of this specification;

[0035] Fig.7D is a temperature distribution diagram of an XZ cross section of a crucible in a crystal growth device corresponding to Example 7 shown in some embodiments of this specification;

[0036] Fig. 7E It is a temperature distribution diagram of the XZ cross section of the melt in the crucible of the crystal growth equipment corresponding to Example 7 shown in some embodiments of this specification. DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For those of ordinary skill in the art, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation. It should be understood that the drawings are for illustration and description purposes only and are not intended to limit the scope of the present application. It should be understood that the drawings are not drawn to scale.

[0038] Taking silicon carbide crystal as an example of semiconductor crystal, the current process of growing silicon carbide crystal using liquid phase method includes: placing carbon raw material, silicon raw material and flux in a crucible, heating the raw materials and flux to form a melt; then placing silicon carbide seed crystal on the liquid surface of the melt, due to the supercooling at the seed crystal, carbon precipitates on the solid-liquid interface of the seed crystal, and combines with silicon to form silicon carbide crystal.

[0039] In the process of liquid phase growth, the dissolution and precipitation of carbon (C) in the solution is a very important indicator of the growth process. To ensure that the crystal growth can proceed stably, the dissolution of carbon at the crucible wall and the precipitation at the seed crystal end need to be balanced. If the carbon dissolution is greater than the carbon precipitation, the carbon in the crystal will gradually be enriched, and spontaneous nucleation of SiC will occur; if the carbon dissolution is less than the carbon precipitation, crystal growth will be difficult due to insufficient solute. At the same time, convection for the transport of carbon will also affect the supply of carbon during the growth process. If you want to grow SiC crystals with good enough crystal quality and sufficient thickness, you need to ensure that the above three items are balanced with each other, which greatly increases the difficulty of SiC liquid phase growth.

[0040] In view of this, some embodiments of the present specification provide a crucible for crystal growth. By redesigning the structure of the crucible, the fluid flow field in the growth chamber during the crystal growth process can be controlled to form a fast path, ensure the smooth growth of the crystal, effectively reduce the impurity content and defects in the crystal, improve the growth efficiency of the crystal, and achieve higher efficiency and higher quality crystal growth.

[0041] Figure 1 is a schematic diagram of an XZ cross-section of a crucible according to some embodiments of the present specification; Figure 2 is an XY cross-sectional schematic diagram of a crucible according to some embodiments of the present specification.

[0042] Crucible 110 is a component for providing a place for crystal growth. In some embodiments, the material of crucible 110 may include but is not limited to graphite. In some embodiments, the material of crucible 110 may include graphite. In some embodiments, the shape of crucible 110 may include but is not limited to cylindrical, rectangular or cube, etc. For example, crucible 110 may be a cylindrical barrel, a rectangular barrel, etc.

[0043] In some embodiments, the crucible 110 may include a bottom wall and a side wall. The side wall is arranged around the top of the bottom wall. The bottom wall and the side wall are arranged around to form a chamber for accommodating the melt 120. In some embodiments, the outside of the crucible 110 may be provided with a heat preservation structure. For example, the heat preservation structure may be a graphite felt, etc. During the crystal growth process, the heat preservation structure can play a role in uniform temperature. In some embodiments, the heat preservation structure can be arranged on the top of the crucible 110. In some embodiments, the heat preservation structure can also be arranged around the outside of the crucible 110. By providing the heat preservation structure, the temperature inside the crucible 110 can be maintained or adjusted, thereby affecting the growth of silicon carbide crystals in the crystal growth equipment.

[0044] The melt 120 is a material in a molten state. The material is a raw material for growing a crystal. The raw material may include a material for supplying a seed crystal to grow into a crystal. In some embodiments, the component of the raw material of the silicon carbide crystal may include SiC.

[0045] In some embodiments, the raw material may be a powder, granular and / or bulk material. In some embodiments, the particle size of the material may be one of 30 μm to 50 μm, 35 μm to 50 μm, 40 μm to 50 μm, 45 μm to 50 μm, 30 μm to 45 μm, 35 μm to 45 μm, 35 μm to 40 μm, 30 μm to 40 μm, 35 μm to 40 μm, 30 μm to 35 μm, 40 μm to 45 μm, etc.

[0046] In some embodiments, the chamber may be a space enclosed by the inner wall of the side wall of the crucible 110, and the shape and size of the growth chamber are related to the shape and size of the inner wall. In some embodiments, the cross-sectional shape of the growth chamber may be circular, rectangular, or square.

[0047] In some embodiments, Figure 1 and Figure 2 As shown, taking the crucible 110 as a cylindrical barrel as an example, the cross-sectional shapes of the chamber, inner wall 110-2 and outer wall 110-1 of the crucible 110 are all circular. The width D1 of the crucible 110 may refer to the diameter of the cross-sectional shape corresponding to the crucible 110, and the width D2 of the chamber may refer to the diameter of the cross-sectional shape corresponding to the chamber.

[0048] The cross section is a plane perpendicular to the central axis O1 of the crucible 110. In some embodiments, a reference coordinate system can be obtained by taking the center of the bottom wall of the crucible 110 as the origin, the radial direction of the crucible 110 as the X-axis, the central axis O1 of the crucible 110 as the Z-axis, and the radial direction perpendicular to both the X-axis and the Z-axis as the Y-axis. The cross section is the plane formed by the X-axis and the Y-axis.

[0049] In some embodiments, the crucible 110 has multiple sizes. In some embodiments, the width D1 of the crucible 110 may range from 280 mm to 325 mm (not included), 325 mm to 360 mm (not included), 360 mm to 400 mm, etc. In some embodiments, the width D1 of the crucible 110 may be one of 320 mm, 330 mm, 380 mm, etc. Among them, the width of the crucible 110 may be the diameter of the outer wall 110-1 of the crucible 110. In the embodiments of this specification, 280 mm to 325 mm (not included) may be used as the first size of the crucible 110, 325 mm to 360 mm (not included) may be used as the second size of the crucible 110, and 360 mm to 400 mm may be used as the third size of the crucible 110.

[0050] It should be noted that the above description of the three sizes of the crucible 110 is for illustrative purposes only and is not intended to limit the scope of this specification. The size of the crucible 110 can be set according to actual production requirements, and this specification does not limit this. When the size of the crucible 110 is any one of the three sizes mentioned above, the width D2 of the chamber can be 280 mm. In some embodiments, the width D2 of the chamber can also be other values, which can be set according to actual production requirements, and this specification does not limit this.

[0051] In some embodiments, the crucible 110 may be a barrel-shaped structure with a certain wall thickness. For example, the crucible 110 may be a cylindrical barrel body, which includes a bottom wall and a side wall. For another example, the crucible 110 may be a rectangular barrel body, which includes a bottom wall and a side wall. The bottom wall and the side wall of the crucible 110 have a certain thickness.

[0052] In some embodiments, the thickness of the bottom wall of the crucible 110 may be uniform, that is, the thickness of any point in the bottom wall of the crucible 110 may be the same. In some embodiments, the thickness of the bottom wall of the crucible 110 may range from 10 mm to 30 mm, 15 mm to 30 mm, 20 mm to 30 mm, 25 mm to 30 mm, 10 mm to 25 mm, 15 mm to 25 mm, 20 mm to 25 mm, 10 mm to 20 mm, 15 mm to 20 mm, 10 mm to 15 mm, etc. In some embodiments, the thickness of the bottom wall of the crucible 110 may range from 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, etc.

[0053] In some embodiments, the thickness of the side wall of the crucible 110 may be non-uniform, that is, the thickness at different locations on the side wall of the crucible 110 may be different.

[0054] In some embodiments, Figure 2 As shown, the side wall of the crucible 110 includes an inner wall 110-2 and an outer wall 110-1, and the interval between the inner wall 110-2 and the outer wall 110-1 is the thickness of the side wall of the crucible 110. When the thickness of the side wall of the crucible 110 is uneven, the intervals between the inner wall position and the outer wall position in different radial directions of the crucible 110 are different.

[0055] In some embodiments, Figure 1 and Figure 2 As shown, the wall thickness of the crucible 110 includes a first wall thickness value L1 and a second wall thickness value L2. The first wall thickness value L1 is the maximum value of the wall thickness of the crucible 110, and the second wall thickness value L2 is the minimum value of the wall thickness of the crucible 110. The first wall thickness value L1 is different from the second wall thickness value L2.

[0056] In the embodiments of this specification, unless otherwise specified, the wall thickness of the crucible 110 may refer to the wall thickness of the side wall of the crucible 110 .

[0057] In some embodiments, when the cross-sectional shape corresponding to the inner wall 110-2 of the crucible 110 is different from the cross-sectional shape corresponding to the outer wall 110-1 of the crucible 110, the wall thickness of the side wall of the crucible 110 may be uneven. For example, the cross-sectional shape corresponding to the inner wall 110-2 of the crucible 110 may be an ellipse, and the cross-sectional shape corresponding to the outer wall 110-1 of the crucible 110 may be a circle.

[0058] In other embodiments, when the cross-sectional shape corresponding to the inner wall 110-2 of the crucible 110 is the same as the cross-sectional shape corresponding to the outer wall 110-1 of the crucible 110, and the cross-sectional shape corresponding to the inner wall 110-2 of the crucible 110 (e.g., circular) is not concentric with the cross-sectional shape corresponding to the outer wall 110-1 of the crucible 110 (e.g., circular), the wall thickness of the side wall of the crucible 110 may be made uneven. For example, on the same cross section, when the geometric center of the cross-sectional shape of the inner wall 110-2 does not coincide with the geometric center of the cross-sectional shape of the outer wall 110-1, the cross-sectional shape corresponding to the inner wall 110-2 of the crucible 110 is not concentric with the cross-sectional shape corresponding to the outer wall 110-1 of the crucible 110.

[0059] In some embodiments, on the same cross-section, when the geometric center of the cross-sectional shape corresponding to the inner wall 110-2 and the geometric center of the cross-sectional shape corresponding to the outer wall 110-1 are offset only on the X-axis, that is, the Y value of the geometric center of the cross-sectional shape corresponding to the inner wall 110-2 is different from the X value of the geometric center of the cross-sectional shape corresponding to the outer wall 110-1, when the Y values ​​are the same, the cross-sectional shape corresponding to the inner wall 110-2 of the crucible 110 can be made non-concentric with the cross-sectional shape corresponding to the outer wall 110-1 of the crucible 110.

[0060] You can refer to Figure 2 Understand the following example: Taking the cross-sectional shape as the center of a circle as an example, in a reference coordinate system with the center of the bottom wall of the crucible 110 as the origin, the radial direction of the crucible 110 as the X-axis, the central axis O1 of the crucible 110 as the Z-axis, and the radial direction perpendicular to both the X-axis and the Z-axis as the Y-axis, the center of the circle corresponding to the cross-sectional shape of the inner wall 110-2 and the center of the circle corresponding to the cross-sectional shape of the outer wall 110-1 are offset on the X-axis, that is, the X value in the center coordinates of the cross-sectional shape of the inner wall 110-2 is different from the X value in the center coordinates of the cross-sectional shape of the outer wall 110-1, but the Y value in the center coordinates is the same. At this time, the cross-sectional shape corresponding to the inner wall 110-2 is not concentric with the cross-sectional shape corresponding to the outer wall 110-1, so that the wall thickness of the side wall of the crucible 110 is uneven, and the two wall thickness values ​​of the crucible 110 on the X-axis are respectively the first wall thickness value L1 and the second wall thickness value L2.

[0061] Taking the cross-sectional shape as the center of the circle as an example, in other embodiments, the center of the cross-sectional shape corresponding to the inner wall 110-2 is offset from the center of the cross-sectional shape corresponding to the outer wall 110-1 on the Y axis, that is, the Y value in the center coordinates of the cross-sectional shape corresponding to the inner wall 110-2 is different from the Y value in the center coordinates of the cross-sectional shape corresponding to the outer wall 110-1, but the X value in the center coordinates is the same. At this time, the cross-sectional shape corresponding to the inner wall 110-2 is not concentric with the cross-sectional shape corresponding to the outer wall 110-1, so that the wall thickness of the side wall of the crucible 110 is uneven, and the two wall thickness values ​​of the crucible 110 on the Y axis are respectively the first wall thickness value L1 and the second wall thickness value L2.

[0062] Taking the cross-sectional shape as the center of the circle as an example, in other embodiments, the center of the circle corresponding to the cross-sectional shape of the inner wall 110-2 and the center of the circle corresponding to the cross-sectional shape of the outer wall 110-1 may also be offset on both the X-axis and the Y-axis, that is, the X value and Y value in the center coordinates of the cross-sectional shape of the inner wall 110-2 are different from the X value and Y value in the center coordinates of the cross-sectional shape of the outer wall 110-1.

[0063] In some embodiments, the crucible wall position forming the first wall thickness value L1 is different from the crucible wall position forming the second wall thickness value L2. The crucible wall position forming the first wall thickness value or the second wall thickness value includes an inner wall position and an outer wall position in the same radial direction.

[0064] In some embodiments, the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 are located on opposite sides of the central axis O2 of the inner wall 110-2 of the crucible 110. When the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 are located on opposite sides of the central axis O2 of the inner wall 110-2 of the crucible 110, the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 are in the same radial direction. As an example only, if the crucible wall position forming the first wall thickness value L1 is located in the negative direction of the X-axis, then the crucible wall position forming the second wall thickness value L2 is located in the positive direction of the X-axis, and at this time, the angle between the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 is 180 degrees.

[0065] In other embodiments, the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 may be located on non-opposite sides of the central axis O2 of the inner wall 110-2 of the crucible 110. For example, the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 may be located on the X-axis and the Y-axis, respectively, and the angle between the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 is 90 degrees. As an example only, when the inner wall 110-2 and / or the outer wall 110-1 of the crucible 110 are elliptical, that is, the cross-sectional shapes of the inner wall 110-2 and the outer wall 110-1 are elliptical, and the ellipse of the cross section of the inner wall 110-2 is perpendicular to the major axis of the ellipse of the cross section of the outer wall 110-1, the angle between the crucible wall position forming the first wall thickness value L1 and the crucible wall position forming the second wall thickness value L2 is 90 degrees.

[0066] In some embodiments of the present specification, by setting the side wall thickness of the crucible to be uneven, the temperature and flow rate distribution around the seed crystal can be asymmetric, and the transmission path of the carbon solute can be significantly reduced without affecting the total area of ​​the liquid surface, the growth rate can be increased, the solute concentration can be balanced, and higher efficiency and higher quality crystal growth can be achieved. By setting the crucible wall position forming the first wall thickness value and the crucible wall position forming the second wall thickness value to be located on opposite sides of the central axis of the inner wall of the crucible, it can be ensured that the crucible has a large capacity and a regular shape, and occupies a small space.

[0067] In some embodiments, the shapes of the inner wall 110 - 2 and the outer wall 110 - 1 of the crucible 110 may be the same. In some embodiments, the cross-sectional shape of the inner wall 110 - 2 may be the same as the cross-sectional shape of the outer wall 110 - 1 .

[0068] In some embodiments, the inner wall 110 - 2 and the outer wall 110 - 1 of the crucible 110 are both cylindrical, and the inner wall 110 - 2 and the outer wall 110 - 1 are parallel to the central axis and are spaced apart from each other.

[0069] In some embodiments, when the center of the circle corresponding to the cross-sectional shape of the inner wall 110-2 is offset from the center of the circle corresponding to the cross-sectional shape of the outer wall 110-1 on the X-axis, on the Y-axis, or on both the X-axis and the Y-axis, the central axis O2 of the inner wall 110-2 is parallel to the central axis O1 of the outer wall 110-1 and there is a gap between them.

[0070] In some embodiments, when the size of the crucible 110 is the first size (e.g., 280 mm to 325 mm (not included)), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be one of 5 mm to 10 mm, etc. In some embodiments, when the size of the crucible 110 is the first size (e.g., 280 mm to 325 mm (not included)), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be one of 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. In some preferred embodiments, when the size of the crucible 110 is the first size (e.g., 280 mm to 325 mm (not included)), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be 10 mm.

[0071] In some embodiments, when the size of the crucible 110 is the second size (e.g., 325 mm to 360 mm (not included)), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be one of 5 mm to 20 mm, etc. In some embodiments, when the size of the crucible 110 is the second size (e.g., 325 mm to 360 mm (not included)), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be one of 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, etc. In some preferred embodiments, when the size of the crucible 110 is the second size (e.g., 325 mm to 360 mm (not included)), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be 20 mm.

[0072] In some embodiments, when the size of the crucible 110 is the third size (e.g., 360 mm to 400 mm), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be one of 5 mm to 40 mm, etc. In some embodiments, when the size of the crucible 110 is the third size (e.g., 360 mm to 400 mm), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be one of 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, etc. In some preferred embodiments, when the size of the crucible 110 is the third size (e.g., 360 mm to 400 mm), the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 may be 40 mm.

[0073] It should be noted that, taking the crucible 110 as a cylindrical shape, the sum of the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1, the second wall thickness value L2 and the radius of the cavity is equal to the radius of the crucible 110. For example, when the radius of the cavity is 140 mm, the radius of the crucible 110 is 160 mm, and the second wall thickness value L2 is 15 mm, the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 is 5 mm. For another example, when the radius of the cavity is 140 mm, the radius of the crucible 110 is 165 mm, and the second wall thickness value L2 is 15 mm, the interval between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 is 10 mm.

[0074] In some embodiments, the first wall thickness value L1 is different from the second wall thickness value L2. In some embodiments, the ratio of the first wall thickness value L1 to the second wall thickness value L2 is greater than 1.

[0075] In some embodiments, the ratio of the first wall thickness value L1 to the second wall thickness value L2 is 1.5 to 20.0. In some embodiments, the ratio of the first wall thickness value L1 to the second wall thickness value L2 can also be 2.0 to 20.0, 4.0 to 20.0, 6.0 to 20.0, 8.0 to 20.0, 10.0 to 20.0, 12.0 to 20.0, 14.0 to 20.0, 16.0 to 20.0, 18.0 to 20.0, 1.5 to 18.0, 2.0 to 18 .0, 4.0~18.0, 6.0~18.0, 8.0~18.0, 10.0~18.0, 12.0~18.0, 14.0~18.0, 16.0~18.0, 1.5~16.0, 2.0~16.0, 4.0~16.0, 6.0~16.0, 8.0~16.0, 10.0~16.0, 12.0~ 16.0, 14.0-16.0, 1.5-14.0, 2.0-14.0, 4.0-14.0, 6.0-14.0, 8.0-14.0, 10.0-14.0, 12.0-14.0, 1.5-12.0, 2.0-12.0, 4.0-12.0, 6.0-12.0, 8.0-12.0, 10.0- 12.0, 1.5-10.0, 2.0-10.0, 4.0-10.0, 6.0-10.0, 8.0-10.0, 1.5-8.0, 2.0-8.0, 4.0-8.0, 6.0-8.0, 1.5-6.0, 2.0-6.0, 4.0-6.0, 1.5-4.0, 2.0-4.0, etc. In some embodiments, the ratio of the first wall thickness value L1 to the second wall thickness value L2 can also be 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, 20.0, etc.

[0076] In some embodiments, the first wall thickness value L1 is at least greater than or equal to 10 mm, and the second wall thickness value L2 is at least greater than or equal to 10 mm.

[0077] In some embodiments, the first wall thickness value L1 ranges from 10 mm to 100 mm, and the second wall thickness value L2 ranges from 10 mm to 30 mm.

[0078] In some embodiments, the range of the first wall thickness value L1 can be 10mm-90mm, 10mm-80mm, 10mm-70mm, 10mm-60mm, 10mm-50mm, 10mm-40mm, 10mm-30mm, 20mm-100mm, 20mm-90mm, 20mm-80mm, 20mm-70mm, 20mm-60mm, 20mm-50mm, 20mm-40mm, 20mm-30mm, 30mm-100mm, 30mm-90mm, 30mm-80mm, 30mm-70mm, 30mm-60mm, 30mm-50mm, One of 30mm~40mm, 40mm~100mm, 40mm~90mm, 40mm~80mm, 40mm~70mm, 40mm~60mm, 40mm~50mm, 50mm~100mm, 50mm~90mm, 50mm~80mm, 50mm~70mm, 50mm~60mm, 60mm~100mm, 60mm~90mm, 60mm~80mm, 60mm~70mm, 70mm~100mm, 70mm~90mm, 70mm~80mm, 80mm~100mm, 80mm~90mm, 90mm~100mm, etc. In some embodiments, the first wall thickness value L1 can be one of 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, etc.

[0079] In some embodiments, the second wall thickness value L2 may range from 10 mm to 25 mm, 10 mm to 20 mm, 10 mm to 15 mm, 15 mm to 30 mm, 15 mm to 25 mm, 15 mm to 20 mm, 20 mm to 30 mm, 20 mm to 25 mm, 25 mm to 30 mm, etc. In some embodiments, the second wall thickness value L2 may range from 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, etc.

[0080] In other embodiments, the inner wall 110-2 and / or the outer wall 110-1 of the crucible 110 is an elliptical cylinder, and the crucible 110 is an eccentric structure. For example, when the inner wall 110-2 of the crucible 110 is an elliptical cylinder and the outer wall 110-1 is a cylindrical shape, the crucible 110 is an eccentric structure. For another example, when the inner wall 110-2 of the crucible 110 is a cylindrical shape and the outer wall 110-1 is an elliptical cylinder, the crucible 110 is an eccentric structure. For another example, when both the inner wall 110-2 and the outer wall 110-1 of the crucible 110 are elliptical cylinders, the crucible 110 is an eccentric structure.

[0081] In some embodiments of the present specification, when the inner wall and the outer wall of the crucible are both cylindrical, the central axis of the inner wall and the outer wall are parallel and spaced, and the cross-sectional shape corresponding to the inner wall is not concentric with the cross-sectional shape corresponding to the outer wall, so that the crucible is designed as an eccentric structure. The inner wall and / or the outer wall of the crucible are designed as an elliptical cylinder, so that the crucible is designed as an eccentric structure. By designing the crucible as an eccentric structure, the temperature close to the side wall of the crucible can be different, so as to effectively control the fluid flow field in the growth chamber during the crystal growth process. By designing the crucible as an eccentric structure, the eddy current near the seed crystal holder can also be affected when the seed crystal rod rotates, so that the eddy current on the thinner side of the crucible side wall is weaker, and the eddy current on the thicker side of the crucible side wall is stronger, so as to control the fluid flow field in the growth chamber during the crystal growth process, form a fast path, ensure the stable growth of the crystal, effectively reduce the impurity content and defects in the crystal, improve the melting efficiency and the growth efficiency of the crystal, and achieve higher efficiency and higher quality crystal growth. By setting the side wall thickness of the crucible to be not less than 10 mm, the risk of the crucible side wall being too thin and being melted through can be reduced.

[0082] Some embodiments of the present specification provide a crystal growth device, which includes the crucible 110 described in any one of the aforementioned embodiments.

[0083] Figure 3 It is a schematic diagram of the structure of the crystal growth equipment shown in some embodiments of this specification.

[0084] The crystal growth device 100 can be used to prepare crystals. In some embodiments, the crystal growth device 100 can prepare crystals based on a liquid phase method or the like. In some embodiments, the crystals can include but are not limited to silicon carbide crystals, aluminum nitride crystals, zinc oxide crystals, or zinc antimonide crystals.

[0085] like Figure 3 As shown, the crystal growth apparatus 100 includes a seed crystal holder 130. The spacing distance between the seed crystal holder 130 and the inner wall 110-2 of the crucible 110 includes a first distance and a second distance, the first distance being the maximum spacing distance, and the second distance being the minimum spacing distance; the first distance and the second distance are different.

[0086] The seed crystal holder 130 is a component for setting the seed crystal. The seed crystal can be a small crystal having the same crystal orientation as the crystal to be grown, which can be used as a seed for growing the crystal. In some embodiments, the seed crystal can be made based on a physical vapor transport (PVT) method, a chemical vapor deposition (CVD) method, or a liquid phase method. In some embodiments, the size of the seed crystal can be 4 inches, 8 inches, etc. The type of the seed crystal can be a 4H-SiC seed crystal, a 6H-SiC seed crystal, etc.

[0087] In some embodiments, the seed crystal holder 130 may be fixedly connected to the seed crystal rod 140. In some embodiments, the seed crystal rod 140 may rotate and rise and fall in the crucible 110, thereby driving the seed crystal holder 130 to rotate and rise and fall in the crucible 110. For example, the seed crystal rod 140 may drive the seed crystal holder 130 to descend from the top of the crucible 110 to the growth chamber of the crucible 110, and further be inserted into the melt 120.

[0088] In some embodiments, a through hole is provided in the central area of ​​the upper cover of the crucible 110, and the seed rod 140 can pass through the through hole. The through hole is not in contact with the seed rod 140, and the seed rod 140 can rotate in the through hole.

[0089] In some embodiments, the shape of the seed tray 130 may include but is not limited to a cylindrical shape, a rectangular parallelepiped shape, a cube shape, etc. For example, the seed tray 130 may be cylindrical, a rectangular parallelepiped shape, etc.

[0090] In some embodiments, the cross-sectional shape of the seed tray 130 may be circular. Figure 2 As shown, taking the cross-sectional shapes of the seed crystal holder 130, the inner wall 110-2 and the outer wall 110-1 as circular as an example, in some embodiments, the cross-sectional shape corresponding to the seed crystal holder 130 is concentric with the cross-sectional shape corresponding to the outer wall 110-1. When the cross-sectional shape corresponding to the inner wall 110-2 is not concentric with the cross-sectional shape corresponding to the outer wall 110-1, the cross-sectional shape corresponding to the seed crystal holder 130 is not concentric with the cross-sectional shape corresponding to the inner wall 110-2.

[0091] In some embodiments, when the cross-sectional shape corresponding to the seed crystal holder 130 is not concentric with the cross-sectional shape corresponding to the inner wall 110-2, there are at least two points on the seed crystal holder 130 that are at different distances from the corresponding points on the inner wall 110-2. For a certain point on the seed crystal holder 130, its corresponding point on the inner wall 110-2 may be in the same radial direction as the point on the seed crystal holder 130.

[0092] In some embodiments, the shortest distance between the seed holder 130 and the inner wall 110 - 2 of the crucible 110 may be the shortest distance among a plurality of distances between various points on the seed holder 130 and corresponding points on the inner wall 110 - 2 .

[0093] In some embodiments, the position of the inner wall of the crucible forming the first distance is different from the position of the inner wall of the crucible forming the second distance, wherein the positions of the inner wall of the crucible forming the first distance and the second distance are different positions in the circumferential direction at the same axial height.

[0094] In some embodiments, the inner wall position of the crucible forming the first distance and the inner wall position of the crucible forming the second distance are located on opposite sides of the central axis O2 of the inner wall 110-2 of the crucible 110. When the inner wall position forming the first distance and the inner wall position forming the second distance are located on opposite sides of the central axis O2 of the inner wall 110-2 of the crucible 110, the inner wall position forming the first distance and the inner wall position forming the second distance are in the same radial direction. For example only, if the inner wall position forming the first distance is located in the negative direction of the X-axis, then the inner wall position forming the second distance is located in the positive direction of the X-axis, and the angle between the inner wall position forming the first distance and the inner wall position forming the second distance is 180 degrees.

[0095] In other embodiments, the inner wall position forming the first distance and the inner wall position forming the second distance may be located on non-opposite sides of the central axis O2 of the inner wall 110-2 of the crucible 110. For example, the inner wall position forming the first distance and the inner wall position forming the second distance may be located on the X-axis and the Y-axis, respectively, and the angle between the inner wall position forming the first distance and the inner wall position forming the second distance is 90 degrees. As an example only, when the cross-sectional shapes of the inner wall 110-2 and the outer wall 110-1 are elliptical, and the ellipse of the cross section of the inner wall 110-2 is perpendicular to the long axis of the ellipse of the cross section of the outer wall 110-1, the angle between the inner wall position forming the first distance and the inner wall position forming the second distance is 90 degrees.

[0096] In some embodiments, the first distance is different from the second distance. In some embodiments, the ratio of the first distance to the second distance is greater than 1.

[0097] In some embodiments, the ratio of the first distance to the second distance is 1.5 to 19.0. In some embodiments, the ratio of the first distance to the second distance may also be 2.0-19.0, 4.0-19.0, 6.0-19.0, 8.0-19.0, 10.0-19.0, 12.0-19.0, 14.0-19.0, 16.0-19.0, 18.0-19.0, 1.5-18.0, 2.0-18.0, 4.0-18.0, 6.0-18.0, 8.0-18.0, 10.0-18.0, 12.0-18.0, 14.0-19.0, 16.0-19.0, 18.0-19.0, 1.5-16.0, 2.0-16.0, 4.0-16.0, 6.0-16.0, 8.0-16.0, 10.0-19.0, 12.0-16 .0, 14.0-16.0, 1.5-14.0, 2.0-14.0, 4.0-14.0, 6.0-14.0, 8.0-14.0, 10.0-14.0, 12.0-14.0, 1.5-12.0, 2.0-12.0, 4.0-12.0, 6.0-12.0, 8.0-12.0, 10.0-1 2.0, 1.5-10.0, 2.0-10.0, 4.0-10.0, 6.0-10.0, 8.0-10.0, 1.5-8.0, 2.0-8.0, 4.0-8.0, 6.0-8.0, 1.5-6.0, 2.0-6.0, 4.0-6.0, 1.5-4.0, 2.0-4.0, etc. In some embodiments, the ratio of the first distance to the second distance can also be 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0, etc.

[0098] In some embodiments, the first distance ranges from 50 mm to 95 mm, and the second distance ranges from 5 mm to 50 mm.

[0099] In some embodiments, the first distance may range from 50 mm to 90 mm, 50 mm to 85 mm, 50 mm to 80 mm, 50 mm to 75 mm, 50 mm to 70 mm, 50 mm to 65 mm, 50 mm to 60 mm, 50 mm to 55 mm, 55 mm to 95 mm, 55 mm to 90 mm, 55 mm to 85 mm, 55 mm to 80 mm, 55 mm to 75 mm, 55 mm to 70 mm, 55 mm to 65 mm, 55 mm to 60 mm, 60 mm to 95 mm, 60 mm to 90 mm, 60 mm to 85 mm, 60 mm to 80 mm, 60 mm to 75 mm, 60 mm to 65 mm In some embodiments, the first distance may be one of 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, etc. In some embodiments, the first distance may be one of 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, etc.

[0100] In some embodiments, the second distance may range from 5mm to 45mm, 5mm to 40mm, 5mm to 35mm, 5mm to 30mm, 5mm to 25mm, 5mm to 20mm, 5mm to 15mm, 5mm to 10mm, 10mm to 50mm, 10mm to 45mm, 10mm to 40mm, 10mm to 35mm, 10mm to 30mm, 10mm to 25mm, 10mm to 20mm, 10mm to 15mm, 15mm to 50mm, 15mm to 45mm, 15mm to 40mm, 15mm to 35mm, 15mm to 30mm, 15mm to 25mm In some embodiments, the second distance may be one of 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc. In some embodiments, the second distance may be one of 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc.

[0101] In some embodiments, when the first distance and the second distance are within the above range, it is necessary to satisfy that the sum of the first distance, the second distance and the diameter of the seed crystal holder is equal to the diameter D2 of the melt.

[0102] In some embodiments of the present specification, when the pot wall position forming the first distance and the pot wall position forming the second distance are located on opposite sides of the central axis of the inner wall of the crucible, the seed crystal holders located on both sides of the central axis of the inner wall are at different distances from the inner wall. The temperature of the melt near the thinner side wall of the crucible is higher, so that the temperature corresponding to the seed crystal on the side of the seed crystal holder close to the inner wall is higher, while the temperature corresponding to the seed crystal on the side of the seed crystal holder far from the inner wall is lower. When the crucible rotates, the melt near the thicker side wall of the crucible begins to heat up, which can gradually reduce the temperature gradient in the growth chamber. When the temperature gradient decreases, the fluidity of the melt can be improved.

[0103] During the rotation of the seed crystal holder, the solid-liquid interface and the crystal in the melt co-rotate, causing the crystal surface to have viscosity, which will form forced convection when subjected to centrifugal force. Through the eccentric design of the crucible, during the rotation of the seed crystal holder, the eddy current on the thinner side of the crucible side is weaker, while the eddy current on the thicker side of the crucible side is stronger, thereby controlling the fluid flow field in the growth chamber during the crystal growth process, providing a path for atmosphere transmission, reducing convection, effectively reducing the impurity content and defects in the crystal, and improving the crystal growth efficiency.

[0104] In some embodiments, a furnace body 150 is further provided in the crystal growth apparatus 100. The furnace body 150 can accommodate other structures in the crystal growth apparatus 100. For example, the furnace body 150 can accommodate the crucible 110, the seed crystal holder 130, and the like.

[0105] In some embodiments, the central axis O1 of the outer wall 110 - 1 of the crucible 110 , the central axis of the furnace body 150 , and the central axis of the seed crystal holder 130 coincide with each other.

[0106] In some embodiments, the distance between the central axis O2 of the inner wall 110-2 of the crucible 110 and the central axis of the furnace body 150 is 5mm to 45mm, that is, the distance between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1 is 5mm to 45mm. In some embodiments, the distance between the central axis O2 of the inner wall 110-2 of the crucible 110 and the central axis of the furnace body 150 can also be 5mm to 40mm, 5mm to 35mm, 5mm to 30mm, 5mm to 25mm, 5mm to 20mm, 5mm to 15mm, 5mm to 10mm, 10mm to 45mm, 10mm to 40mm, 10mm to 35mm, 10mm to 30mm, 10mm to 25mm, 10mm to 20mm, 10mm to 15mm, 15mm to 45mm, 15mm to 40mm, 15mm to In some embodiments, the distance between the central axis O2 of the inner wall 110-2 of the crucible 110 and the central axis of the furnace body 150 can also be 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, etc. For more information about the distance between the central axis O2 of the inner wall 110-2 and the central axis O1 of the outer wall 110-1, see Figure 1 , Figure 2 Related description in .

[0107] In some embodiments of the present specification, an eccentric crucible can be obtained by designing the central axis of the outer wall of the crucible, the central axis of the furnace body and the central axis of the seed crystal holder to coincide with each other, and making the central axis of the inner wall of the crucible and the central axis of the furnace body non-coincident.

[0108] In some embodiments, a heating assembly 160 is further disposed in the furnace body 150 .

[0109] The heating assembly 160 can be used to heat the crucible 110 to provide a temperature field required for crystal growth to prepare a crystal. In some embodiments, heating the material by the heating assembly 160 can sublime the material to grow a crystal on the growth surface of the seed crystal.

[0110] When the heating assembly 160 heats the crucible 110, a temperature field can be formed inside the crucible 110, so that an axial temperature gradient is formed between the material and the seed crystal. The material decomposes and sublimates into gaseous components under high temperature conditions. Since the temperature at the location of the seed crystal is relatively low, the gaseous components can be driven by the axial temperature gradient to be transferred to the seed crystal in the low temperature zone, and grow and crystallize to form crystals at the seed crystal.

[0111] In some embodiments, the type of the heating component 160 can be a resistance heater. The material of the resistor can include but is not limited to at least one of graphite, tungsten, platinum, molybdenum, tantalum or iridium. Accordingly, the resistance heater can include but is not limited to at least one of a graphite resistance heater, a tungsten resistance heater, a platinum resistance heater, a molybdenum resistance heater, a tantalum resistance heater or an iridium resistance heater.

[0112] In some embodiments, the type of the heating assembly 160 may be an electromagnetic induction heater. In some embodiments, the electromagnetic induction heater may include an induction coil. Under the action of alternating currents of different frequencies, the induction coil may generate eddy currents on the surface of the crucible 110. Under the action of the eddy currents, the electrical energy generated on the surface of the crucible 110 may be converted into thermal energy, and the thermal energy is conducted from the wall of the crucible 110 to the inside of the crucible 110 to heat the crucible 110.

[0113] In some embodiments, the heating assembly 160 may be located outside the crucible 110 . For example, an induction coil is disposed around the outside of the crucible 110 .

[0114] The following takes the case where both the inner and outer walls of the crucible are cylindrical as an example.

[0115] Figure 4 It is a schematic diagram of an XZ cross-section of a crystal growth device according to some embodiments of the present specification. Figure 4 Where H1 is the height of the crystal growth device, H2 is the height of the crucible, L1 is the first thickness value, L2 is the second thickness value, and D2 is the diameter of the inner wall of the crucible. The first thickness value L1 and the second thickness value L2 have different values, so the crucible is an eccentric structure.

[0116] When the crucible size is the first type of size (for example, 320mm), the height of the crystal growth equipment can be set to 1200mm, the height of the crucible can be set to 620mm, the diameter of the inner wall can be set to 280mm, and the height of the chamber can be set to 180mm. Among them, the first thickness value and the second thickness value of the crucible wall thickness can include multiple forms. In Example 1, the first thickness value L1 can be set to 35mm, and the second thickness value L2 can be set to 5mm. At this time, the distance between the center axis of the outer wall and the center axis of the inner wall is 15mm. In Example 2, the first thickness value L1 can be set to 25mm, and the second thickness value L2 can be set to 15mm. At this time, the distance between the center axis of the outer wall and the center axis of the inner wall is 5mm. In Example 3, the first thickness value L1 can be set to 30mm, and the second thickness value L2 can be set to 10mm. At this time, the distance between the center axis of the outer wall and the center axis of the inner wall is 10mm.

[0117] Figure 5A Schematic diagram of magnetic flux distribution of the XZ cross section of the crystal growth device corresponding to Example 1, and schematic diagram of magnetic flux distribution of the XZ cross section of the crystal growth device corresponding to Examples 2 and 3. Figure 5A similar; Figure 5B Schematic diagram of magnetic flux distribution of the crucible in the crystal growth device corresponding to Example 1, and schematic diagram of magnetic flux distribution of the crucible in the crystal growth device corresponding to Examples 2 and 3. Figure 5B similar; Figure 5C Schematic diagram of magnetic flux distribution of the melt in the crucible of the crystal growth device corresponding to Example 1, and schematic diagram of magnetic flux distribution of the melt in the crucible of the crystal growth device corresponding to Examples 2 and 3. Figure 5C similar; Figure 5D is a temperature distribution diagram of the XZ cross section of the crucible in the crystal growth device corresponding to Example 1, and the temperature distribution diagrams of the XZ cross section of the crucible in the crystal growth device corresponding to Examples 2 and 3 are Figure 5D similar; Figure 5E is a temperature distribution diagram of the XZ cross section of the melt in the crucible of the crystal growth device corresponding to Example 1, and the temperature distribution diagram of the XZ cross section of the melt in the crucible of the crystal growth device corresponding to Examples 2 and 3 is Figure 5E similar; Fig. 5F is a streamline diagram of the XZ section of the melt in the crucible of the crystal growth device corresponding to Example 1, and the streamline diagram of the XZ section of the melt in the crucible of the crystal growth device corresponding to Examples 2 and 3 is Fig. 5F similar.

[0118] When the crucible size is the second type of size (for example, 330mm), the height of the crystal growth equipment can be set to 1200mm, the height of the crucible can be set to 620mm, the diameter of the inner wall can be set to 280mm, and the height of the chamber can be set to 180mm. Among them, the first thickness value and the second thickness value of the crucible wall thickness can include multiple forms. In Example 4, the first thickness value L1 can be set to 30mm, and the second thickness value L2 can be set to 20mm. At this time, the distance between the center axis of the outer wall and the center axis of the inner wall is 5mm. In Example 5, the first thickness value L1 can be set to 35mm, and the second thickness value L2 can be set to 15mm. At this time, the distance between the center axis of the outer wall and the center axis of the inner wall is 10mm. In Example 6, the first thickness value L1 can be set to 45mm, and the second thickness value L2 can be set to 5mm. At this time, the distance between the center axis of the outer wall and the center axis of the inner wall is 20mm.

[0119] Fig. 6A Schematic diagram of magnetic flux distribution of the XZ cross section of the crystal growth device corresponding to Example 4, schematic diagram of magnetic flux distribution of the XZ cross section of the crystal growth device corresponding to Examples 5 and 6 Fig. 6A similar; Figure 6B Schematic diagram of magnetic flux distribution of the crucible in the crystal growth device corresponding to Example 4, and schematic diagram of magnetic flux distribution of the crucible in the crystal growth device corresponding to Examples 5 and 6. Figure 6B similar; Figure 6C Schematic diagram of magnetic flux distribution of the melt in the crucible of the crystal growth device corresponding to Example 4, and schematic diagram of magnetic flux distribution of the melt in the crucible of the crystal growth device corresponding to Examples 5 and 6. Figure 6C similar; Fig.6D is the temperature distribution diagram of the XZ cross section of the crucible in the crystal growth device corresponding to Example 4, and the temperature distribution diagram of the XZ cross section of the crucible in the crystal growth device corresponding to Examples 5 and 6 is Fig.6D similar; Fig. 6E is a temperature distribution diagram of the XZ cross section of the melt in the crucible of the crystal growth device corresponding to Example 4, and the temperature distribution diagram of the XZ cross section of the melt in the crucible of the crystal growth device corresponding to Examples 5 and 6 is Fig. 6E similar; Fig. 6F is a streamline diagram of the XZ section of the melt in the crucible of the crystal growth device corresponding to Example 4, and the streamline diagram of the XZ section of the melt in the crucible of the crystal growth device corresponding to Examples 5 and 6 is Fig. 6F similar.

[0120] When the crucible size is the third type of size (for example, 380mm), the height of the crystal growth equipment can be set to 1200mm, the height of the crucible can be set to 620mm, the diameter of the inner wall can be set to 280mm, and the height of the chamber can be set to 180mm. Among them, the first thickness value and the second thickness value of the crucible wall thickness can include multiple forms. In Example 7, the first thickness value L1 can be set to 90mm, and the second thickness value L2 can be set to 10mm. At this time, the distance between the central axis of the outer wall and the central axis of the inner wall is 40mm. For example, in other embodiments, the first thickness value L1 can be set to 80mm, and the second thickness value L2 can be set to 20mm. Other forms of the first thickness value and the second thickness value are no longer listed one by one.

[0121] Fig. 7A It is a schematic diagram of magnetic flux distribution in the XZ cross section of the crystal growth device corresponding to Example 7; Figure 7B Schematic diagram of magnetic flux distribution of the melt in the crucible of the crystal growth equipment corresponding to Example 7; Figure 7C is a temperature distribution diagram of the XZ section of the crystal growth device corresponding to Example 7; Fig.7D is a temperature distribution diagram of the XZ section of the crucible of the crystal growth equipment corresponding to Example 7; Fig. 7E This is a temperature distribution diagram of the XZ cross section of the melt in the crucible of the crystal growth equipment corresponding to Example 7.

[0122] from Figure 5A-5E , Figure 6A-6E and Figure 7A-7E It can be seen that the change of the eccentric structure inside the crucible will not affect the magnetic flux distribution of the crucible. From the perspective of the overall magnetic flux, the shielding effect of the crucible makes it almost non-existent to have magnetic flux distribution inside it; analyzing the melt separately, it can be seen that the magnetic flux shielding ability is relatively weak at the thinner parts of the crucible wall, and there will be a weak magnetic flux effect on the edge of the melt. At this time, the magnetic flux density of the melt is not zero. According to the skin effect, a magnetic flux effect will be generated at the edge of the melt, and small eddy currents will be generated, which will lead to a stronger carbon melting ability at the edge of the melt. At the same time, the increase in the size of the outer wall of the crucible increases the magnetic flux, which leads to a corresponding increase in the temperature generated in the crucible. From Figure 5D , Figure 5E , Fig.6D , Fig. 6E , Figure 7C , Fig.7D and Fig. 7E It can be seen that the eccentric structure inside the crucible causes the temperature on both sides of the seed crystal and the thinner the side wall of the crucible, the higher the temperature of the melt near the wall, and the smaller the low temperature zone corresponding to the seed crystal. At the same time, as the size of the crucible increases, the temperature of the entire melt will also increase accordingly. Fig. 5F and Fig. 6FIt can be seen that the eccentric structure inside the crucible causes asymmetric flow velocity distribution on both sides of the seed crystal. At the same time, the eccentric structure of the crucible will also affect the eddy currents on both sides of the seed crystal formed by the rotation of the rotating rod. The eddy currents on the side away from the crucible wall are weak or do not occur, making the fluid flow field more stable.

[0123] From the above, it can be seen that by designing the crucible as an eccentric structure, the temperature of the melt near the thinner position of the crucible side wall can be made higher, effectively improving the melting efficiency and crystal growth efficiency. At the same time, when the crucible rotates, the uneven melt temperature will not affect the crystal growth. By designing the crucible as an eccentric structure, it can also affect the eddy current near the seed crystal holder when the seed crystal rod rotates, so that the eddy current on the thinner side of the crucible side wall is weaker, and the eddy current on the thicker side of the crucible side wall is stronger, thereby controlling the fluid flow field in the growth chamber during the crystal growth process, providing a path for atmosphere transmission, reducing convection, effectively reducing the impurity content and defects in the crystal, improving the growth efficiency of the crystal, and achieving more efficient and higher quality crystal growth.

[0124] Some embodiments of this specification also disclose a crystal growth method, which prepares a semiconductor crystal by using a crystal growth device 100. For convenience, the following description will be given by taking the preparation of a silicon carbide single crystal as an example. The method may include: controlling the crystal growth device based on device control parameters to achieve crystal growth.

[0125] In some embodiments, after completing at least one of the processes of loading, vacuuming, filling with protective gas, heating, melting, etc., the crystal growth equipment can be controlled based on the equipment control parameters.

[0126] In some embodiments, the polysilicon raw material may be loaded into a quartz crucible. During the loading process, care needs to be taken to keep the raw material and the quartz crucible clean, and also to prevent the crucible from breaking.

[0127] In some embodiments, in order to prevent impurity contamination, the heating chamber needs to be evacuated and flushed with protective gases such as argon or nitrogen during the process of preparing single crystal silicon.

[0128] In some embodiments, the quartz crucible can be heated in a protective gas environment to melt the polysilicon therein. In this process, attention should be paid to preventing edge hanging, bridging and silicon jumping.

[0129] In some embodiments, the equipment control parameters may include the rotation speed of the seed pad 130 and the height of the melt 120 .

[0130] In some embodiments, the rotation speed of the seed crystal holder is 20rpm~150rpm. In some embodiments, the rotation speed of the seed crystal holder can also be 20rpm~140rpm, 20rpm~120rpm, 20rpm~100rpm, 20rpm~80rpm, 20rpm~60rpm, 20rpm~40rpm, 40rpm~150rpm, 40rpm~140rpm, 40rpm~120rpm, 40rpm~100rpm, 40rpm~80rpm, 40rpm~60rpm, 60rpm~150rpm, 60rpm~ In some embodiments, the rotation speed of the seed crystal holder can also be one of 20rpm, 40rpm, 60rpm, 80rpm, 100rpm, 120rpm, 140rpm, 150rpm, 100rpm, 120rpm, 120rpm, 150rpm, 120rpm, 140rpm, etc. In some embodiments, the rotation speed of the seed crystal holder can also be one of 20rpm, 40rpm, 60rpm, 80rpm, 100rpm, 120rpm, 140rpm, 150rpm, etc.

[0131] In some embodiments, the height of melt 120 may be the vertical distance between the highest point of melt 120 surface and the bottom wall of crucible 110. In some embodiments, the height of melt 120 may be the vertical distance between the lowest point of melt 120 surface and the bottom wall of crucible 110.

[0132] In some embodiments, the height of the melt 120 is 10 mm to 80 mm. In some embodiments, the height of the melt 120 can also be one of 10mm~70mm, 10mm~60mm, 10mm~50mm, 10mm~40mm, 10mm~30mm, 10mm~20mm, 20mm~80mm, 20mm~70mm, 20mm~60mm, 20mm~50mm, 20mm~40mm, 20mm~30mm, 30mm~80mm, 30mm~70mm, 30mm~60mm, 30mm~50mm, 30mm~40mm, 40mm~80mm, 40mm~70mm, 40mm~60mm, 40mm~50mm, 50mm~80mm, 50mm~70mm, 50mm~60mm, 60mm~80mm, 60mm~70mm, 70mm~80mm and the like. In some embodiments, the height threshold may be one of 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, etc.

[0133] In some embodiments, the above-mentioned crystal growth method further includes controlling the crucible to rotate. In some embodiments, the rotation speed of the crucible is 20rpm~100rpm. In some embodiments, the rotation speed of the crucible can also be 20rpm~80rpm, 20rpm~60rpm, 20rpm~40rpm, 40rpm~100rpm, 40rpm~80rpm, 40rpm~60rpm, 60rpm~100rpm, 60rpm~80rpm, 80rpm~100rpm, 100rpm~150rpm, 100rpm~140rpm, etc. In some embodiments, the rotation speed of the seed crystal holder can also be 20rpm, 40rpm, 60rpm, 80rpm, 100rpm, etc.

[0134] By controlling the crucible rotation, the impact of uneven melt temperature on crystal growth can be reduced.

[0135] The above preparation process is only used as an example, and the process parameters involved may be different in different embodiments, and the order of the above steps is not unique. The order of the steps may be adjusted in different embodiments, or even one or more steps may be omitted. The above examples should not be understood as limiting the scope of protection of this application.

[0136] The beneficial effects that may be brought about by this embodiment include but are not limited to: (1) during the crystal growth process, the seed crystal rotating at a certain speed contacts the molten raw material, thereby promoting the seed crystal to gradually grow into a larger silicon single crystal under the action of thermodynamics; (2) the obtained crystal growth surface is relatively flat, with a low degree of protrusion, and there are fewer defects such as impurity stripes and vortices in the crystal, and the crystal quality is high.

[0137] This specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

[0138] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A crucible for crystal growth, characterized in that: On any cross section perpendicular to the axis of the crucible, the wall thickness of the crucible includes a first wall thickness value and a second wall thickness value, wherein the first wall thickness value is the maximum value of the wall thickness of the crucible, the second wall thickness value is the minimum value of the wall thickness of the crucible, and the first wall thickness value is different from the second wall thickness value.

2. The crucible according to claim 1, characterized in that The crucible wall position where the first wall thickness value is formed and the crucible wall position where the second wall thickness value is formed are located on opposite sides of the central axis of the inner wall of the crucible.

3. The crucible according to claim 2, characterized in that The inner wall and the outer wall of the crucible are both cylindrical, and the inner wall is parallel to the central axis of the outer wall and is spaced apart from each other.

4. The crucible according to claim 3, characterized in that The ratio of the first wall thickness value to the second wall thickness value is 1.5 to 20.

0.

5. The crucible according to claim 4, characterized in that The first wall thickness value ranges from 10 mm to 100 mm, and the second wall thickness value ranges from 10 mm to 30 mm.

6. The crucible according to claim 1, characterized in that The inner wall and / or outer wall of the crucible is in an elliptical cylindrical shape.

7. A crystal growth device, comprising a seed crystal holder and a crucible according to any one of claims 1 to 6, characterized in that: The spacing distance between the seed crystal holder and the inner wall of the crucible includes a first distance and a second distance, the first distance is the maximum value of the spacing distance, and the second distance is the minimum value of the spacing distance; the first distance and the second distance are different.

8. The crystal growth apparatus according to claim 7, characterized in that: The position of the inner wall of the crucible forming the first distance and the position of the inner wall of the crucible forming the second distance are located on opposite sides of the central axis of the inner wall of the crucible.

9. The crystal growth apparatus according to claim 8, characterized in that The ratio of the first distance to the second distance is 1.5 to 19.0; and / or the range of the first distance is 50 mm to 95 mm, and the range of the second distance is 5 mm to 50 mm.

10. The crystal growth apparatus according to claim 7, characterized in that The crystal growth equipment also includes a furnace body, in which the crucible and the seed crystal holder are located; the central axis of the outer wall of the crucible, the central axis of the furnace body and the central axis of the seed crystal holder coincide with each other, and the distance between the central axis of the inner wall of the crucible and the central axis of the furnace body is 5 mm to 45 mm.

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