A device and method for rapidly growing large-size high-quality cubic silicon carbide single crystals

Abstract

The present invention provides a device and method for rapidly growing large-sized, high-quality cubic silicon carbide single crystals, belonging to the field of crystal growth technology. The device includes a crucible assembly, a seed crystal assembly, a heating assembly arranged outside the crucible assembly, and a heat preservation assembly located between the heating assembly and the crucible assembly; the crucible assembly includes a crucible and a pushing and rotating component arranged below the crucible for pushing and rotating the crucible; the seed crystal assembly includes a seed crystal holder and a lifting and rotating component connected by a mortise and tenon structure, and a locking component for locking the mortise and tenon structure; the lifting and rotating component is used to lift and rotate the seed crystal holder; and a fixing component for fixing a silicon carbide raw material rod is arranged around the seed crystal holder. The device provided by the present invention can effectively overcome the problems of high melt viscosity, poor fluidity, low solute transfer rate, etc., which are caused by low growth temperature and seriously limit the growth speed and quality of the crystal, and meet the process requirements for rapidly growing large-sized cubic silicon carbide single crystals.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal growth, and in particular to a device and method for rapidly growing large-size, high-quality cubic silicon carbide single crystals. Background Art

[0002] As one of the typical representatives of wide bandgap semiconductors, silicon carbide has excellent properties such as large bandgap width, high breakdown field strength, high saturated electron mobility, high thermal conductivity, good thermal stability and chemical stability. It is an ideal substrate material for making high-frequency, high-voltage, high-efficiency, radiation-resistant, high-temperature resistant high-power devices and blue light-emitting diodes, which makes it have huge application prospects in new energy vehicles, high-speed rail transit, aerospace, high-voltage smart grids and clean energy, and has received widespread attention.

[0003] There are many different crystal forms of silicon carbide. Compared with the currently commercially available 4H-SiC crystal form, cubic silicon carbide single crystal (3C-SiC crystal form) has advantages such as higher thermal conductivity, higher carrier mobility, and lower gate oxide layer interface state density. MOS devices based on 3C-SiC can achieve higher operating frequencies, lower on-resistance, and better gate oxide layer stability, which can effectively improve device performance, reliability, and yield. It has very important application advantages in SiC devices of 1200 V and below, especially MOSFET devices, and is even considered to be the most valuable SiC crystal form in the future.

[0004] However, the thermodynamic properties of cubic silicon carbide single crystals determine that it is difficult to prepare them using traditional SiC growth methods and ideas. The liquid phase method, as a new method for growing silicon carbide single crystals, has been proven to be effective in growing cubic silicon carbide single crystals. However, the growth of cubic silicon carbide single crystals needs to be carried out at a lower temperature. The existing cubic silicon carbide single crystal growth device is prone to high melt viscosity, poor fluidity, and low solute transfer rate during the crystal growth process, which severely limits the crystal growth rate and cannot meet the process requirements for the rapid growth of large-size cubic silicon carbide single crystals. Summary of the invention

[0005] In response to one or more technical problems existing in the prior art, the present invention provides a device and method for rapidly growing large-sized, high-quality cubic silicon carbide single crystals. The device provided by the present invention can effectively overcome the problems of high melt viscosity, poor fluidity, and low solute transfer rate caused by low growth temperature that seriously limit the quality and speed of crystal growth, and meet the process requirements for rapidly growing large-sized cubic silicon carbide single crystals.

[0006] The present invention provides a device for rapidly growing large-size high-quality cubic silicon carbide single crystals, the device comprising a crucible assembly, a seed crystal assembly, a heating assembly arranged outside the crucible assembly, and a heat preservation assembly located between the heating assembly and the crucible assembly;

[0007] The crucible assembly includes a crucible and a pushing and rotating component disposed below the crucible for pushing and rotating the crucible;

[0008] The seed crystal assembly includes a seed crystal holder and a lifting and rotating component connected by a mortise and tenon structure, and a locking component for locking the mortise and tenon structure; the lifting and rotating component is used to lift and rotate the seed crystal holder; and a fixing component for fixing the silicon carbide raw material rod is arranged around the seed crystal holder.

[0009] Preferably, the crucible is a graphite crucible, a tantalum carbide crucible, or a graphite crucible with a tantalum carbide coating on the inner wall.

[0010] Preferably, the mortise and tenon structure comprises a mortise and tenon structure arranged at the lower end of the lifting and rotating component and a tenon structure arranged at the upper end of the seed crystal holder; the locking component and the mortise and tenon structure are fixed by threads.

[0011] The present invention also provides a method for rapidly growing large-size, high-quality cubic silicon carbide single crystals, which is implemented by the device described in the first aspect, and the method comprises the following steps:

[0012] S1. placing a flux in a crucible and heating until the flux is completely liquefied to obtain a melt;

[0013] S2. The silicon carbide raw material rod fixed on the seed crystal holder is contacted with the melt, and the seed crystal holder is rotated to obtain a mixed melt;

[0014] S3. The silicon carbide seed crystal is brought into contact with the mixed melt to perform crystal growth to obtain a cubic silicon carbide single crystal; during the crystal growth process, the seed crystal holder is periodically rotated, and the crucible is periodically rotated in the opposite direction with the same period.

[0015] Preferably, each cycle of the periodic rotation includes: the seed crystal holder rotates in the positive direction, accelerates to the first preset speed at the first preset time and maintains it for a second preset time, then decelerates to 0 at the first preset time, then rotates in the reverse direction, accelerates to the first preset speed at the first preset time and maintains it for the second preset time, and finally decelerates to 0 at the first preset time.

[0016] Preferably, each cycle of the reverse periodic rotation includes: the crucible rotates in the reverse direction, accelerates to a second preset speed within a first preset time and maintains the second preset time, then decelerates to 0 within the first preset time, and then rotates in the forward direction, accelerates to a second preset speed within the first preset time and maintains the second preset time, and then decelerates to 0 within the first preset time.

[0017] Preferably, the first preset rotation speed is greater than the second preset rotation speed.

[0018] Preferably, the first preset speed is 10-80 rpm; and / or

[0019] The second preset rotation speed is 5-20 rpm.

[0020] Preferably, the first preset time is 5 to 60 minutes; and / or

[0021] The second preset time is 20 to 120 minutes.

[0022] Preferably, during the crystal growth process, the seed crystal holder is pulled upward at a speed of 100-200 μm / h.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] In the seed crystal assembly of the present invention, the seed crystal holder and the lifting and rotating component are connected by a mortise and tenon structure, and then locked by a locking component tube, so that a firm connection between the lifting and rotating component and the seed crystal holder can be achieved. The structure has good reliability, can withstand greater rotational torque, can meet greater torque transmission requirements, and better achieve high-speed rotation of large-sized crystals in a melt with a high viscosity during crystal growth. It can meet the process requirements of long-term high-speed rotation and lifting growth of large-sized silicon carbide crystals, and overcome the limitations of the existing lifting and rotating component and the seed crystal holder, which is not firmly connected, cannot achieve higher requirements for crystal rotation processes, is difficult to support high-speed rotation of larger-sized crystals, the connection thread is easy to wear or damage, and has poor reusability. In addition, the structure is easy to disassemble and assemble, and there is almost no wear during disassembly and assembly and normal operation. It can be reused many times, which can effectively reduce the corresponding time cost and material cost.

[0025] The present invention fixes the silicon carbide raw material rod on the seed crystal holder and rotates with the seed crystal holder. On the one hand, the stirring of the solution can be strengthened to improve the solute transfer rate. On the other hand, the corrosion and dissolution of the silicon carbide raw material rod can provide Si source and C source for the growth of silicon carbide crystals. It is no longer necessary to provide C source for crystal growth through corrosion crucibles. It can not only avoid the problems of poor growth stability and sustainability caused by corrosion of the crucible, but also realize the repeated use of crucibles and metal raw materials, which is conducive to greatly reducing the cost of crystal growth. In addition, the corrosion and dissolution of the silicon carbide raw material rod can simultaneously provide Si and C elements with a stoichiometric ratio of 1:1 for crystal growth, which can ensure the stability of the chemical components in the melt during the growth of silicon carbide crystals, and is conducive to the long-term stable growth of the crystal growth process. It overcomes the problem that the existing silicon carbide crystal growth method using corrosion crucibles can only provide C elements, and the Si element in the solution is only consumed but not replenished, which is not conducive to the long-term stable growth of silicon carbide crystals.

[0026] The device provided by the present invention connects the seed crystal holder and the pulling rotating component through a mortise and tenon structure and fixes the silicon carbide raw material rod on the seed crystal holder. During the crystal growth process, the seed crystal holder and the crucible are controlled to rotate periodically, which can effectively overcome the problems of high melt viscosity, poor fluidity, and low solute transfer rate caused by low growth temperature, which seriously limit the crystal growth rate, and meet the process requirements for rapidly growing large-sized cubic silicon carbide single crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic structural diagram of a device for rapidly growing large-size, high-quality cubic silicon carbide single crystals provided by the present invention;

[0029] Figure 2 It is a schematic diagram of the assembly of a seed crystal holder and a lifting and rotating component in a device for rapidly growing large-size, high-quality cubic silicon carbide single crystals provided by the present invention;

[0030] Figure 3 It is a schematic diagram of the assembly of a seed crystal holder and a fixing component in a device for rapidly growing large-size, high-quality cubic silicon carbide single crystals provided by the present invention;

[0031] Figure 4 This is a physical picture of a large-sized, high-quality cubic silicon carbide single crystal provided in Example 2 of the present invention;

[0032] Figure 5This is a Raman spectrum test result diagram of a large-sized, high-quality cubic silicon carbide single crystal provided in Example 2 of the present invention;

[0033] Figure 6 This is a rocking curve test result diagram of a large-sized high-quality cubic silicon carbide single crystal provided by Example 2 of the present invention;

[0034] Figure 7 This is a physical picture of a large-sized, high-quality cubic silicon carbide single crystal provided in Example 5 of the present invention;

[0035] Figure 8 This is a physical picture of a large-sized cubic silicon carbide single crystal provided in Comparative Example 1 of the present invention;

[0036] Fig. 9 This is a physical picture of a large-sized cubic silicon carbide single crystal provided in Comparative Example 2 of the present invention;

[0037] Fig.10 This is a physical picture of a large-sized cubic silicon carbide single crystal provided in Comparative Example 3 of the present invention.

[0038] Reference numerals:

[0039] 1- Crucible assembly;

[0040] 11-crucible; 12-promoting rotating parts;

[0041] 2-seed crystal assembly;

[0042] 21-lifting and rotating component; 22-seed crystal holder; 23-fixing component; 24-mortise and tenon structure; 25-tenon structure; 26-locking component;

[0043] 3- Insulation components;

[0044] 4- Heating component;

[0045] 5-Silicon carbide raw material rod;

[0046] 6-Furnace cavity. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0048] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple groups" refers to two or more groups; the terms "connected", "fixed" and the like should be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. The terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including a ..." do not exclude the existence of other identical factors in the process, method, article or device including the elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0049] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present invention are described at the angles shown in the drawings and should not be understood as limiting the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0050] like Figure 1-3 As shown, the present invention provides a device for rapidly growing large-size high-quality cubic silicon carbide single crystals, the device comprising a crucible assembly 1, a seed crystal assembly 2, a heating assembly 4 arranged outside the crucible assembly 1, and a heat preservation assembly 3 located between the heating assembly 4 and the crucible assembly 1;

[0051] The crucible assembly 1 includes a crucible and a pushing and rotating component 12 disposed below the crucible for pushing and rotating the crucible 11;

[0052] The seed crystal assembly 2 includes a seed crystal holder 22 and a lifting and rotating component 21 connected by a mortise and tenon structure, and a locking component 26 for locking the mortise and tenon structure; the lifting and rotating component 21 is used to lift and rotate the seed crystal holder 22; a fixing component 23 for fixing the silicon carbide raw material rod 5 is arranged around the seed crystal holder 22.

[0053] In the seed crystal assembly of the present invention, the seed crystal holder and the lifting and rotating component are connected by a mortise and tenon structure, and then locked by a locking component tube, so that a firm connection between the lifting and rotating component and the seed crystal holder can be achieved. The structure has good reliability, can withstand greater rotational torque, can meet greater torque transmission requirements, and better achieve high-speed rotation of large-sized crystals in a melt with a high viscosity during crystal growth. It can meet the process requirements of long-term high-speed rotation and lifting growth of large-sized silicon carbide crystals, and overcome the limitations of the existing lifting and rotating component and the seed crystal holder, which is not firmly connected, cannot achieve higher requirements for crystal rotation processes, is difficult to support high-speed rotation of larger-sized crystals, the connection thread is easy to wear or damage, and has poor reusability. In addition, the structure is easy to disassemble and assemble, and there is almost no wear during disassembly and assembly and normal operation. It can be reused many times, which can effectively reduce the corresponding time cost and material cost.

[0054] The present invention fixes the silicon carbide raw material rod on the seed crystal holder and rotates with the seed crystal holder. On the one hand, the stirring of the solution can be strengthened to improve the solute transfer rate. On the other hand, the corrosion and dissolution of the silicon carbide raw material rod can provide Si source and C source for the growth of silicon carbide crystals. It is no longer necessary to provide C source for crystal growth through corrosion crucibles. It can not only avoid the problems of poor growth stability and sustainability caused by corrosion of the crucible, but also realize the repeated use of crucibles and metal raw materials, which is conducive to greatly reducing the cost of crystal growth. In addition, the corrosion and dissolution of the silicon carbide raw material rod can simultaneously provide Si and C elements with a stoichiometric ratio of 1:1 for crystal growth, which can ensure the stability of the chemical components in the melt during the growth of silicon carbide crystals, and is conducive to the long-term stable growth of the crystal growth process. It overcomes the problem that the existing silicon carbide crystal growth method using corrosion crucibles can only provide C elements, and the Si element in the solution is only consumed but not replenished, which is not conducive to the long-term stable growth of silicon carbide crystals.

[0055] According to some preferred embodiments, the device further comprises a furnace chamber 6 .

[0056] According to some preferred embodiments, the crucible 11 is a graphite crucible, a tantalum carbide crucible, or a graphite crucible with a tantalum carbide coating on the inner wall.

[0057] According to some preferred embodiments, the mortise and tenon structure includes a mortise and tenon structure 24 disposed at the lower end of the lifting and rotating component and a tenon structure 25 disposed at the upper end of the seed crystal holder; the locking component 26 is fixed to the mortise and tenon structure 24 by threads.

[0058] The mortise and tenon structure in the present invention can be any mortise and tenon structure that can simultaneously realize axial relative rotation and movement, preferably but not limited to at least one of T-shaped, stem-shaped, Y-shaped, L-shaped, and F-shaped. The shape of the mortise and tenon structure is not specifically limited, preferably but not limited to one of a cylinder, a triangular prism, a quadrangular prism, and other prisms. The material of the lifting and rotating component, the seed crystal holder, and the locking sleeve is preferably high-purity graphite or molybdenum.

[0059] In some preferred embodiments of the present invention, the locking component 26 is a hollow cylindrical structure, the inner diameter of which matches the outer diameter of the tongue and groove structure 24, and the inner wall of the locking component 26 and the outer wall of the tongue and groove structure 24 are fixed by a threaded structure.

[0060] The present invention also provides a method for rapidly growing large-size, high-quality cubic silicon carbide single crystals, which is implemented by the device described in the first aspect, and the method comprises the following steps:

[0061] S1. placing a flux in a crucible and heating until the flux is completely liquefied to obtain a melt;

[0062] S2. The silicon carbide raw material rod fixed on the seed crystal holder is contacted with the melt, and the seed crystal holder is rotated to obtain a mixed melt;

[0063] S3. The silicon carbide seed crystal is brought into contact with the mixed melt to perform crystal growth to obtain a cubic silicon carbide single crystal; during the crystal growth process, the seed crystal holder is periodically rotated, and the crucible is periodically rotated in the opposite direction with the same period.

[0064] The present invention first melts the flux to obtain a melt, and controls the pulling and rotating component to make the silicon carbide raw material rod fixed on the seed crystal holder contact with the melt (the silicon carbide seed crystal is not in contact with the melt at this time), and the silicon carbide raw material rod rotates along with the seed crystal holder, so as to promote the rapid dissolution of the silicon carbide raw material rod in the melt and ensure the uniform distribution of Si and C solutes in the melt, so as to obtain a mixed melt; then the pulling and rotating component is controlled to make the silicon carbide seed crystal contact with the mixed melt to perform crystal growth, and during the crystal growth process, the seed crystal holder is periodically rotated, and the crucible is reversely periodically rotated with the same period, and the silicon carbide raw material rod is driven by the seed crystal holder to rotate in the solution, which can promote the rapid dissolution of the silicon carbide raw material rod on the one hand, and provide sufficient and stable Si and C solutes for the growth of SiC crystals, and on the other hand, the transmission rate of Si and C solutes can be accelerated under the stirring action of the silicon carbide raw material rod, so as to improve the growth rate of SiC crystals.

[0065] After the crystal growth is completed, if the raw material rod is consumed, the crystal growth can be carried out again after it is replaced, and other raw materials do not need to be added to the crucible.

[0066] The device provided by the present invention connects the seed crystal holder and the pulling rotating component through a mortise and tenon structure and fixes the silicon carbide raw material rod on the seed crystal holder. During the crystal growth process, the seed crystal holder and the crucible are controlled to rotate periodically, which can effectively overcome the problems of high melt viscosity, poor fluidity, and low solute transfer rate caused by low growth temperature, which seriously limit the crystal growth rate, and meet the process requirements for rapidly growing large-sized cubic silicon carbide single crystals.

[0067] According to some preferred embodiments, each cycle of the periodic rotation includes: the seed crystal holder rotates in a positive direction, accelerates to a first preset speed at a first preset time and maintains it for a second preset time, then decelerates to 0 at the first preset time, and then rotates in a reverse direction, accelerates to the first preset speed at the first preset time and maintains it for a second preset time, and finally decelerates to 0 at the first preset time.

[0068] According to some preferred embodiments, each cycle of the reverse periodic rotation includes: the crucible rotates in the reverse direction, accelerates to a second preset speed at a first preset time and maintains the second preset time, then decelerates to 0 at the first preset time, and then rotates in the forward direction, accelerates to a second preset speed at a first preset time and maintains the second preset time, and then decelerates to 0 at the first preset time. It should be noted that the reverse periodic rotation of the crucible of the present invention can also be performed in other ways, as long as the period of the reverse periodic rotation of the crucible is the same as the period of the periodic rotation of the seed crystal holder.

[0069] The rotation of the seed crystal holder in the preparation process of the mixed melt of the present invention is to ensure that the silicon and carbon elements are evenly dispersed in the melt during the silicon carbide dissolution process, and the rotation speed of the seed crystal holder is not specifically limited. In some preferred embodiments of the present invention, the seed crystal holder is also periodically rotated during the preparation process of the mixed melt, and the crucible is periodically rotated in the opposite direction with the same period, so as to improve the dissolution rate of the raw material rod and the uniformity of the dispersion of silicon and carbon elements.

[0070] According to some preferred embodiments, the first preset rotational speed is greater than the second preset rotational speed.

[0071] According to some preferred embodiments, the first preset rotation speed is 10-80 rpm (for example, it can be 10 rpm, 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm or 80 rpm);

[0072] According to some preferred embodiments, the second preset rotation speed is 5-20 rpm (for example, it may be 5 rpm, 8 rpm, 10 rpm, 12 rpm, 15 rpm, 18 rpm or 20 rpm).

[0073] According to some preferred embodiments, the first preset time is 5 to 60 min (for example, it may be 5 min, 10 min, 20 min, 30 min, 40 min, 50 min or 60 min).

[0074] According to some preferred embodiments, the second preset time is 20 to 120 min (for example, it can be 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min).

[0075] According to some preferred embodiments, during the crystal growth process, the seed crystal holder is pulled upward at a speed of 100-200 μm / h (for example, 100 μm / h, 120 μm / h, 140 μm / h, 150 μm / h, 160 μm / h, 180 μm / h or 200 μm / h).

[0076] In order to more clearly illustrate the technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the examples. The present invention does not specifically limit the sources of the reagents used in the examples and comparative examples, and the reagents can be directly purchased or synthesized by themselves.

[0077] The testing method for the performance data of the cubic silicon carbide crystals grown in the embodiments of the present invention and the comparative examples is as follows:

[0078] Crystal size and quality measurement: Place the processed crystal on standard coordinate paper or standard caliper to confirm the size; Use laser confocal Raman scattering to measure the crystal form; Use XRD diffractometer to measure the rocking curve of the crystal to determine its crystalline quality.

[0079] Example 1

[0080] like Figure 1-3 As shown, a device for rapidly growing large-size high-quality cubic silicon carbide single crystals comprises:

[0081] A crucible assembly 1, a seed crystal assembly 2, a heating assembly 4 arranged outside the crucible assembly 1, and a heat preservation assembly 3 located between the heating assembly 4 and the crucible assembly 1; wherein the heat preservation assembly 3 is a heat preservation material, and the heating assembly 4 is an induction heating coil;

[0082] The crucible assembly 1 includes a crucible 11 and a driving and rotating component 12 for driving the crucible to rotate;

[0083] The seed crystal assembly 2 includes a lifting and rotating component 21 and a seed crystal holder 22 connected by a mortise and tenon structure, and a locking component 26 for locking the mortise and tenon structure; the mortise and tenon structure includes a tenon structure 24 arranged at the lower end of the lifting and rotating component and a tenon structure 25 arranged at the upper end of the seed crystal holder; the locking component 26 is fixed to the tenon structure 24 by threads.

[0084] The pulling and rotating component 21 is used to pull and rotate the seed crystal holder 22 ; a fixing component 23 for fixing the silicon carbide raw material rod 5 is arranged around the seed crystal holder 22 .

[0085] Example 2

[0086] A method for rapidly growing large-size, high-quality cubic silicon carbide single crystals is implemented by the apparatus of embodiment 1, comprising:

[0087] S1. After assembling the device, close the furnace chamber and evacuate the chamber. When the chamber pressure is less than or equal to 1×10 -4 After Pa, high-purity argon is filled into the furnace chamber as a protective gas, a flux is placed in a crucible (with an inner diameter of 130 mm), and the crucible is heated to completely liquefy the flux raw material in the crucible, and the flux is heated until it is completely liquefied to obtain a melt, wherein the flux includes Fe, Mn and Cr in a mass ratio of 3:5:2;

[0088] S2. Control the pulling rotating component to make the silicon carbide raw material rod fixed on the seed crystal holder contact with the melt (the silicon carbide seed crystal does not contact with the melt at this time), and rotate the seed crystal holder for 1 hour to obtain a mixed melt.

[0089] S3. The temperature of the mixed melt is stabilized at 1600°C, and a silicon carbide seed crystal (with a diameter of 100 mm) is contacted with the mixed melt to grow a crystal to obtain a cubic silicon carbide single crystal; during the crystal growth process, the seed crystal holder is periodically rotated, and the crucible is reversely periodically rotated at the same period, and the seed crystal holder is pulled upward at a speed of 200 μm / h. Wherein, each cycle in the periodic rotation includes: the seed crystal holder rotates in the positive direction, accelerates to 50 rpm in 10 minutes and maintains for 60 minutes, then decelerates to 0 in 10 minutes, and then rotates in the reverse direction, accelerates to 50 rpm in 10 minutes and maintains for 60 minutes, and finally decelerates to 0 in 10 minutes; each cycle in the reverse periodic rotation includes: controlling the rotating component to make the crucible rotate in the reverse direction, accelerates to a second preset speed of 20 rpm in 10 minutes and maintains for 60 minutes, then decelerates to 0 in 10 minutes, and then rotates in the positive direction, accelerates to 20 rpm in 10 minutes and maintains for 60 minutes, and then decelerates to 0 in 10 minutes.

[0090] The actual 4-inch cubic silicon carbide single crystal grown in this example is as follows: Figure 4As shown in the figure, the crystal growth cutoff surface is very bright, indicating that the crystal quality is very high and the crystal growth rate can reach 150 μm / h. The Raman spectrum test results of the crystal are shown in the figure. Figure 5 As shown in FIG. 1 , it is proved that the crystal grown in this embodiment is a cubic silicon carbide crystal. The rocking curve test results of the crystal are shown in FIG. Figure 6 As shown, the average half-width of the crystal rocking curve is 31.7 arc seconds, proving that the crystal quality is good.

[0091] Example 3

[0092] A method for rapidly growing large-size, high-quality cubic silicon carbide single crystals is implemented by the apparatus of embodiment 1, comprising:

[0093] S1. After assembling the device, close the furnace chamber and evacuate the chamber. When the chamber pressure is less than or equal to 1×10 -4 After Pa, high-purity argon is filled into the furnace chamber as a protective gas, a flux is placed in a crucible (with an inner diameter of 130 mm), and the crucible is heated to completely liquefy the flux raw material in the crucible, and the flux is heated until it is completely liquefied to obtain a melt, wherein the flux includes Fe, Mn and Cr in a mass ratio of 3:5:2;

[0094] S2. Control the pulling rotating component to make the silicon carbide raw material rod fixed on the seed crystal holder contact with the melt (the silicon carbide seed crystal does not contact with the melt at this time), and rotate the seed crystal holder for 1 hour to obtain a mixed melt.

[0095] S3. The temperature of the mixed melt is stabilized at 1600°C, and a silicon carbide seed crystal (with a diameter of 100 mm) is contacted with the mixed melt to grow a crystal to obtain a cubic silicon carbide single crystal; during the crystal growth process, the seed crystal holder is periodically rotated, and the crucible is periodically rotated in the same reverse cycle, and the seed crystal holder is pulled upward at a speed of 200 μm / h. Wherein, each cycle of the periodic rotation includes: the seed crystal holder rotates in the positive direction, accelerates to a speed of 80 rpm in 5 min and maintains for 80 min, then decelerates to 0 in 5 min, rotates in the reverse direction, accelerates to 80 rpm in 5 min and maintains for 80 min, and finally decelerates to 0 in 5 min; each cycle of the reverse periodic rotation includes: controlling the rotating part to make the crucible rotate in the reverse direction, accelerates to 5 rpm in 5 min and maintains for 80 min, then decelerates to 0 in 5 min, rotates in the positive direction, accelerates to 5 rpm in 5 min and maintains for 80 min, and then decelerates to 0 in 5 min.

[0096] The growth cutoff surface of the 4-inch cubic silicon carbide single crystal grown in this embodiment is very bright, indicating that the crystal quality is very high and the growth rate of the crystal is increased to 260 μm / h.

[0097] Example 4

[0098] A method for rapidly growing large-size, high-quality cubic silicon carbide single crystals is implemented by the apparatus of embodiment 1, comprising:

[0099] S1. After assembling the device, close the furnace chamber, evacuate the furnace chamber, and when the furnace chamber pressure is less than or equal to 1×10-4Pa, fill the furnace chamber with high-purity argon as a protective gas, place the flux in a crucible (with an inner diameter of 130mm), and heat the crucible to completely liquefy the flux raw material in the crucible, and heat until the flux is completely liquefied to obtain a melt, wherein the flux includes Fe, Mn and Cr in a mass ratio of 3:5:2;

[0100] S2. Control the pulling rotating component to make the silicon carbide raw material rod fixed on the seed crystal holder contact with the melt (the silicon carbide seed crystal does not contact with the melt at this time), and rotate the seed crystal holder for 1 hour to obtain a mixed melt.

[0101] S3. The temperature of the mixed melt is stabilized at 1600°C, and a silicon carbide seed crystal (with a diameter of 100 mm) is contacted with the mixed melt to grow a crystal to obtain a cubic silicon carbide single crystal; during the crystal growth process, the seed crystal holder is periodically rotated, and the crucible is periodically rotated in the same reverse cycle, and the seed crystal holder is pulled upward at a speed of 200 μm / h. Wherein, each cycle of the periodic rotation includes: the seed crystal holder rotates in the positive direction, accelerates to a speed of 10 rpm in 5 min and maintains for 120 min, then decelerates to 0 in 5 min, and then rotates in the reverse direction, accelerates to 10 rpm in 5 min and maintains for 120 min, and finally decelerates to 0 in 5 min; each cycle of the reverse periodic rotation includes: controlling the rotating part to make the crucible rotate in the reverse direction, accelerates to 5 rpm in 5 min and maintains for 120 min, then decelerates to 0 in 5 min, and then rotates in the positive direction, accelerates to 5 rpm in 5 min and maintains for 120 min, and then decelerates to 0 in 5 min.

[0102] The growth cutoff surface of the 4-inch cubic silicon carbide single crystal grown in this example is very bright, indicating that the crystal quality is very high, and the growth rate of the crystal is reduced to 60 μm / h.

[0103] It should be noted that, except for the crystal growth rate of the cubic silicon carbide single crystals grown in Examples 3 and 4 of the present invention being different from that in Example 2, the size, morphology and crystal quality of the grown single crystals are basically the same as those in Example 2, which are not listed here one by one.

[0104] Example 5

[0105] It is basically the same as Example 2, except that the seed crystal and the crucible are enlarged to grow a 6-inch cubic silicon carbide single crystal, wherein the inner diameter is 180 mm and the seed crystal diameter is 150 mm.

[0106] The actual photo of the 6-inch cubic silicon carbide single crystal grown in this embodiment is as follows: Figure 7 As shown, the crystal diameter is greater than 150 mm, and the crystal growth cutoff surface is very bright, indicating that the crystal quality is very high. The crystal growth rate is 100 μm / h.

[0107] Comparative Example 1

[0108] It is basically the same as Example 2, except that during the growth process, the seed crystal holder rotates clockwise at a speed of 80 rpm until the crystal growth is completed.

[0109] like Figure 8 As shown, there are many groove-shaped defects on the surface of the cubic silicon carbide crystal single crystal grown in Comparative Example 1, which is caused by the uneven distribution of solutes during crystal growth. The growth results show that the high-speed positive and negative periodic rotation of the seed crystal during crystal growth is conducive to improving the uniformity of solute distribution in the melt, and can achieve rapid and high-quality growth of cubic silicon carbide crystals.

[0110] Comparative Example 2

[0111] It is basically the same as Example 2, except that: the device for growing silicon carbide crystals in liquid phase does not have a fixing component 23 for fixing the silicon carbide raw material rod 5. During the growth of silicon carbide crystals, in the process of preparing the melt, the flux and silicon are mixed, and the mixture is completely liquefied to obtain a melt: wherein the flux includes Fe, Mn and Cr in a mass ratio of 3:5:2, and the mass ratio of the flux to silicon is 3:2.

[0112] like Fig. 9 As shown, the cubic silicon carbide crystal single crystal grown in Comparative Example 2 has a multi-island growth morphology, which is mainly caused by the serious shortage of solute supply during the growth process. The growth results show that the periodic rotation of the raw material rod in the melt can effectively increase the solute supply rate during the growth process, which is more conducive to the rapid and high-quality growth of cubic silicon carbide crystals.

[0113] Comparative Example 3

[0114] It is basically the same as Example 2, except that: each cycle in the periodic rotation includes: the seed crystal holder rotates in the positive direction, accelerates to 100 rpm in 10 minutes and maintains for 60 minutes, then decelerates to 0 in 10 minutes, and then rotates in the reverse direction, accelerates to 100 rpm in 10 minutes and maintains for 60 minutes, and finally decelerates to 0 in 10 minutes; each cycle in the reverse periodic rotation includes: controlling the rotating component to make the crucible rotate in the reverse direction, accelerates to a second preset speed of 20 rpm in 10 minutes and maintains for 60 minutes, then decelerates to 0 in 10 minutes, and then rotates in the positive direction, accelerates to 20 rpm in 10 minutes and maintains for 60 minutes, and then decelerates to 0 in 10 minutes.

[0115] The crystal growth rate is improved, but because the rotation speed is too high, the stirring amplitude of the raw material rod is too large, resulting in instability of the crystal growth interface and poor crystal growth quality. Fig.10 shown.

[0116] Comparative Example 4

[0117] In the device for growing cubic silicon carbide single crystals used in Comparative Example 1, the conventional threaded connection method is used to control the pulling rotating component and the seed crystal holder, that is, a threaded screw is provided on the back of the seed crystal holder, and a screw hole matching the thread is provided at one end of the seed crystal holder connected to the pulling rotating component, and the two are connected by threads.

[0118] After the crystal growth was completed, the crucible was taken out and it was found that the seed crystal holder and the crystal had fallen into the crucible. Most of the seed crystal holder connected by threads was embedded in the solidified alloy, indicating that the seed crystal holder had fallen into the melt during the crystal growth process. It can be seen that the conventional threaded connection method cannot achieve high-speed forward and reverse rotation, and cannot meet the process requirements for the rapid growth of large-sized cubic silicon carbide single crystals.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for rapidly growing large-size, high-quality cubic silicon carbide single crystals, characterized in that: The method comprises the following steps: S1. placing a flux in a crucible and heating until the flux is completely liquefied to obtain a melt; S2. The silicon carbide raw material rod fixed on the seed crystal holder is contacted with the melt, and the seed crystal holder is rotated to obtain a mixed melt; S3. The silicon carbide seed crystal is contacted with the mixed melt to grow a crystal to obtain a cubic silicon carbide single crystal; during the crystal growth process, the seed crystal holder is periodically rotated, and the crucible is periodically rotated in the same period in the reverse direction; Each cycle of the periodic rotation includes: the seed crystal holder rotates in the positive direction, accelerates to the first preset speed at the first preset time and maintains the second preset time, then decelerates to 0 at the first preset time, and then rotates in the reverse direction, accelerates to the first preset speed at the first preset time and maintains the second preset time, and finally decelerates to 0 at the first preset time; each cycle of the reverse periodic rotation includes: the crucible rotates in the reverse direction, accelerates to the second preset speed at the first preset time and maintains the second preset time, then decelerates to 0 at the first preset time, and then rotates in the positive direction, accelerates to the second preset speed at the first preset time and maintains the second preset time, and then decelerates to 0 at the first preset time; the first preset speed is greater than the second preset speed; the first preset speed is 10-80 rpm; the second preset speed is 5-20rpm; the first preset time is 5-60 min; the second preset time is 20-120 min; The method is implemented by a device for rapidly growing large-size, high-quality cubic silicon carbide single crystals, the device comprising a crucible assembly, a seed crystal assembly, a heating assembly arranged outside the crucible assembly, and a heat preservation assembly located between the heating assembly and the crucible assembly; The crucible assembly includes a crucible and a pushing and rotating component disposed below the crucible for pushing and rotating the crucible; The seed crystal assembly includes a seed crystal holder and a lifting and rotating component connected by a mortise and tenon structure, and a locking component for locking the mortise and tenon structure; the lifting and rotating component is used to lift and rotate the seed crystal holder; and a fixing component for fixing the silicon carbide raw material rod is arranged around the seed crystal holder.

2. The method according to claim 1, characterized in that The crucible is a graphite crucible, a tantalum carbide crucible or a graphite crucible with a tantalum carbide coating on the inner wall.

3. The method according to claim 1, characterized in that The mortise and tenon structure comprises a mortise and tenon structure arranged at the lower end of the lifting and rotating component and a tenon structure arranged at the upper end of the seed crystal holder; the locking component is fixed to the mortise and tenon structure by means of threads.

4. The method according to claim 1, characterized in that: During the crystal growth process, the seed crystal holder is pulled upward at a speed of 100-200 μm / h.

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