Device and method for controlling diameter of growing crystal and silicon carbide crystal

Abstract

The invention relates to a device and a method for controlling the diameter of a growing crystal and a silicon carbide crystal. The device comprises a seed crystal rod, wherein the lower end surface of the seed crystal rod along a first direction is used for arranging a seed crystal; the control ring assembly comprises a plurality of rings which are detachably connected in sequence in the first direction, and the inner circumferential wall of each ring has a preset inner diameter; in every two adjacent rings, the preset inner diameter of the lower side ring is larger than the preset inner diameter of the upper side ring. Among the plurality of rings, the ring connected to the seed crystal rod is sleeved on the seed crystal rod and sleeved on the seed crystal. The device can be used for forming various crystals with preset diameters.

Description

Technical Field

[0001] The present disclosure relates to the technical field of semiconductor crystal growth, and in particular to a device and method for controlling the diameter of a growing crystal, and a silicon carbide crystal. Background Art

[0002] Silicon carbide has the advantages of wide band gap, high breakdown electric field strength, high electron saturation mobility and strong radiation resistance. It has broad application prospects in high-power converters and high-frequency communications. Silicon carbide grown by liquid phase method has attracted widespread attention in recent years due to its advantages such as high crystal quality, easy diameter expansion and easy P-type doping.

[0003] In the liquid phase growth process, it is necessary to dissolve carbon in a molten silicon solution at high temperature, and then the silicon carbide seed crystal is brought into contact with the solution to reduce the temperature of the solution around the seed crystal to a supercooled state, and then the supersaturated solution around the seed crystal is used to epitaxially grow single crystal silicon carbide. It is difficult to control the crystal diameter during the growth process, and generally larger silicon carbide crystals are grown and then processed. For example, to obtain a 2-inch substrate, it is necessary to grow a crystal with a diameter greater than 2 inches and then cut it into 2 inches. This leads to a huge waste of raw materials and also increases the processing steps and difficulty of processing.

[0004] If substrates of different diameters are to be obtained, the only options are to grow silicon carbide crystals multiple times or to cut silicon carbide crystals that are much larger than the substrate size. Both methods increase the difficulty and cost of processing, and large-sized silicon carbide crystals are prone to problems such as excessive edge growth and edge cracking. Summary of the invention

[0005] Based on this, it is necessary to provide a device and method for controlling the diameter of a growing crystal and a silicon carbide crystal in order to address the problem that substrates of different diameters are difficult to manufacture with good quality.

[0006] An embodiment of the present disclosure provides a device for controlling the diameter of a growing crystal, the device comprising: a seed crystal rod, the lower end face of the seed crystal rod along a first direction being used for setting a seed crystal; and a control ring assembly, the control ring assembly comprising a plurality of rings detachably connected in sequence along a first direction, the inner circumferential wall of each ring having a predetermined inner diameter; among two adjacent rings, the predetermined inner diameter of the lower ring is greater than the predetermined inner diameter of the upper ring; among the plurality of rings, the ring connected to the seed crystal rod is sleeved on the seed crystal rod and sleeved on the seed crystal.

[0007] By providing multiple detachably connected rings, several rings can be selected to be connected during operation according to needs. By configuring the inner circumferential walls of the rings, the device can control the diameter of the growing crystal and can be used to form crystals of various predetermined diameters. The device for controlling the diameter of the growing crystal of the disclosed embodiment is easy to use.

[0008] In some embodiments, the inner circumferential wall of each of the plurality of rings gradually expands from top to bottom, and the lower end of the inner circumferential wall of the ring has a predetermined inner diameter.

[0009] Such an arrangement can ensure that the space within each ring is suitable for forming a crystal, and facilitates the transition between multiple rings, which is beneficial for making the manufactured crystal have different predetermined diameters at different positions along the axial direction.

[0010] In some embodiments, a plurality of chamfered rings are further included, wherein the chamfered rings are detachably connected to the lower portion of the corresponding ring, and the arc-shaped chamfers of the chamfered rings are bent inwardly relative to the inner peripheral wall of the ring.

[0011] In this way, a chamfer ring can be set on the bottom ring used each time. The arc chamfer of the chamfer ring is helpful to prevent the cracking of the crystal edge.

[0012] In some embodiments, the inner circumferential wall of the ring is a conical surface, and the outer circumferential wall of the ring is a conical surface; the upper end surface or the lower end surface of the ring is used to dock with another corresponding ring, and the two adjacent rings are connected by screws; in the two adjacent rings, the screws extend from the outer circumferential wall of the upper ring through the lower end surface of the upper ring, the upper end surface of the lower ring, and into the lower ring.

[0013] In this way, the ring has a thinner wall, which is lighter and easier to control temperature. The installation position of the screw matches the shape of the ring, making the connection structure simple and durable, which is conducive to manufacturing high-quality crystals.

[0014] In some embodiments, the outer circumference of the seed rod is connected to the corresponding ring by screws, and the outer circumference of the seed rod is provided with at least two threaded holes opposite to each other along the second direction.

[0015] With such arrangement, the connection structure is simple and the force can be balanced, thereby ensuring that the control ring assembly is reliably connected to the seed crystal rod.

[0016] In some embodiments, the material of the ring is boron nitride.

[0017] With such an arrangement, the introduction of impurities can be avoided when manufacturing silicon carbide crystals, and at the same time, the ring of boron nitride material is conducive to ensuring structural strength and connection strength.

[0018] In some embodiments, the predetermined inner diameter of the rings connected to the seed rod is 2 inches, and the predetermined inner diameter of each ring increases by 0.5 inches from the previous ring.

[0019] With such an arrangement, the device can be used to manufacture crystals having predetermined diameters of 2 inches, 2.5 inches, 3 inches, etc. at different positions, thereby meeting crystal manufacturing requirements.

[0020] In some embodiments, the apparatus for controlling the diameter of a growing crystal further comprises a crucible for accommodating the control ring assembly and for accommodating at least a portion of the seed rod.

[0021] Thus configured, the apparatus can be used to produce crystals by the liquid phase method.

[0022] Exemplarily, the device for controlling the diameter of the growing crystal also includes a thermal insulation outer lining and a heater, wherein the thermal insulation outer lining surrounds the crucible and the heater is located outside the crucible; the seed rod can be raised and lowered relative to the crucible along a first direction; and the material of the crucible is graphite.

[0023] Thus configured, the apparatus can be used to produce silicon carbide crystals by a liquid phase method.

[0024] The embodiment of the present disclosure provides a method for controlling the diameter of a growing crystal, which utilizes the aforementioned apparatus for controlling the diameter of a growing crystal to manufacture a crystal having a predetermined diameter through a liquid phase method.

[0025] The method of the embodiment of the present disclosure is easy to perform and can form crystals of various predetermined diameters. In addition, the edge state of the crystals formed by the method is good.

[0026] The embodiment of the present disclosure provides a silicon carbide crystal, which is manufactured according to the steps of the aforementioned method for controlling the diameter of a growing crystal.

[0027] The silicon carbide crystal has low manufacturing cost, little waste and good quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the working state of the device for controlling the diameter of the growing crystal according to the embodiment of the present disclosure;

[0029] Figure 2 is a schematic top view of a control ring assembly in an embodiment of the present disclosure;

[0030] Figure 3 is a schematic front view of a control ring assembly in an embodiment of the present disclosure;

[0031] Figure 4 is a schematic top view of a first ring in an embodiment of the present disclosure;

[0032] Figure 5 is a schematic front view of the first ring in an embodiment of the present disclosure;

[0033] Figure 6 is a schematic left side view of the first ring in an embodiment of the present disclosure;

[0034] Figure 7 is a schematic top view of the second ring in an embodiment of the present disclosure;

[0035] Figure 8 is a schematic front view of the second ring in an embodiment of the present disclosure;

[0036] Fig. 9 It is a schematic diagram of the structure of the ring and the chamfered ring in the embodiment of the present disclosure;

[0037] Fig.10 It is a schematic diagram of the structure of the ring and the chamfered ring in the embodiment of the present disclosure;

[0038] Fig.11 A schematic diagram of the structure of a wafer manufactured by the device for controlling the diameter of a growing crystal according to an embodiment of the present disclosure;

[0039] Fig.12 The present invention is a flowchart of a method for controlling the diameter of a growing crystal according to an embodiment of the present invention.

[0040] Explanation of the reference numerals: 1. seed crystal rod; 2. seed crystal; 3. control ring assembly; 4. ring; 401. inner circumferential wall; 402. outer circumferential wall; 403. upper end face; 404. lower end face; 405. first screw hole; 406. second screw hole; 407. third screw hole; 40. chamfer ring; 408. arc chamfer; 41. first ring; 42. second ring; 43. third ring; 44. fourth ring; 5. crucible; 6. insulation lining; 7. heater; 100. device for controlling the diameter of the growing crystal; 200. solution; 300. crystal. DETAILED DESCRIPTION

[0041] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present disclosure more obvious and understandable, the specific implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the embodiments of the present disclosure. However, the embodiments of the present disclosure can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the embodiments of the present disclosure, so the embodiments of the present disclosure are not limited by the specific examples of the embodiments disclosed below.

[0042] In the description of the embodiments of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "perpendicular", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present disclosure.

[0043] In the embodiments of the present disclosure, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. Exemplarily, the first screw hole may also be referred to as the second screw hole, and the second screw hole may also be referred to as the first screw hole. In the description of the embodiments of the present disclosure, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In the embodiments of the present disclosure, unless otherwise clearly specified and limited, the terms "connected", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a flexible connection, or a rigid connection along at least one direction; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or directly connected with the presence of an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly limited. The terms "installed", "set", "fixed", etc. can be broadly understood as connection. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0046] As used in the present disclosure, the terms "layer" and "region" refer to a portion of a material that includes an area with a certain thickness. The layer can extend horizontally, vertically and / or along a tapered surface. A layer can be an area of ​​a uniform or non-uniform continuous structure, and its thickness perpendicular to the extension direction may not be greater than the thickness of the continuous structure. A layer can include multiple layers, which can be multiple stacked layers or multiple layers extending discretely. The shapes of various areas and layers in the drawings and their relative sizes and positional relationships are only exemplary, and may actually deviate due to manufacturing tolerances or technical limitations, and the design can be adjusted according to actual needs.

[0047] refer to Figure 1 , Figure 1The device for controlling the diameter of a growing crystal in an embodiment of the present disclosure is shown. In an exemplary embodiment, the device 100 for controlling the diameter of a growing crystal includes a seed crystal rod 1 and a control ring assembly 3. Exemplarily, the device 100 for controlling the diameter of a growing crystal also includes a seed crystal 2, and the seed crystal 2 can be fixed to the seed crystal rod 1 before each growth.

[0048] The seed crystal rod 1 extends substantially along a first direction, which may be parallel to the Z-axis direction. The lower end surface of the seed crystal rod 1 along the first direction is used to arrange the seed crystal 2. Exemplarily, the seed crystal rod 1 and the seed crystal 2 may have the same cross-sectional shape.

[0049] refer to Figure 2 and Figure 3 The control ring assembly 3 includes a plurality of rings 4 which are sequentially and detachably connected along a first direction, such as Figures 4 to 8 As shown, the structures of the four rings may be different. The control ring assembly 3 may also include a connecting structure (not shown) for connecting to the ring 4. Figure 1 As shown, the control ring assembly 3 is connected to the seed crystal rod 1 , and the control ring assembly 3 can be sleeved on the seed crystal 2 , and the forming space formed therein is docked with the seed crystal 2 .

[0050] refer to Figure 2 and Figure 3 For example, the control ring assembly 3 is provided with four rings 4, which are the first ring 41, the second ring 42, the third ring 43 and the fourth ring 44 from top to bottom along the Z-axis direction. The control ring assembly 3 can be configured with a smaller number of rings 4 or a larger number of rings 4 according to the use requirements. One set of control ring assembly 3 can meet different requirements. Multiple sets of control ring assembly 3 can also be provided.

[0051] Among the multiple rings 4, the ring 4 connected to the seed crystal rod 1 is sleeved on the seed crystal rod 1, and the ring 4 is the first ring 41, and the first ring 41 is also sleeved on the seed crystal 2. Figure 5 , the top of the first ring 41 is adapted to the seed crystal rod 1, and the inner diameter D0 of the mounting end of the first ring 41 can be the same as the outer diameter of the seed crystal rod 1. Exemplarily, when the diameter of the seed crystal rod 1 is configured, the inner diameter D0 of the mounting end of the first ring 41 can be determined, and the predetermined inner diameter D1 of the first ring 41 can also be configured as required. The predetermined inner diameters of other rings 4 such as the second ring 42 and the slope of the inner circumferential wall 401 can also be configured as required, and different rings 4 can also be selected. By providing a plurality of detachably connected rings 4, it is possible to select a number of rings 4 to be connected during work as required.

[0052] refer to Figure 5 and Figure 8The inner wall 401 of each ring 4 has a predetermined inner diameter, for example, the inner wall 401 of the first ring 41 has a first predetermined inner diameter D1, and the inner wall 401 of the second ring 42 has a second predetermined inner diameter D2. The height H of the ring 4 is also the thickness of the crystal 300 formed therein.

[0053] For example, the thickness of the second ring 42 is H, the inner diameter of the upper end surface 403 thereof can be the same as the first predetermined inner diameter D1, and the inner diameter of the lower end surface 404 is the second predetermined inner diameter D2. In order to match the seed crystal rod 1, the inner diameter D0 of the upper end surface 403 of the first ring 41 can be smaller than the diameter of the required crystal 300, and then the part close to the lower end is used. Optionally, the dimension of the inner circumferential wall 401 of the first ring 41 along the Z-axis direction is H.

[0054] Exemplarily, the diameter of the seed rod 1 is 40 mm, the inner diameter D0 of the first ring 41 is 40 mm, and the first predetermined inner diameter D1 may be 2 inches.

[0055] In other embodiments, the first ring 41 is only used for installation and fixation to facilitate the connection of the lower ring 4 to the seed rod 1 , and the space inside the first ring 41 serves as a transition to ensure that a crystal 300 with a desired predetermined inner diameter is formed in the lower ring 4 .

[0056] Exemplarily, the control ring assembly 3 includes two adjacent rings 4 , for example, the first ring 41 is adjacent to the second ring 42 , the second ring 42 is adjacent to the third ring 43 , and the third ring 43 is adjacent to the fourth ring 44 .

[0057] In two adjacent rings 4 , the predetermined inner diameter of the lower ring is greater than the predetermined inner diameter of the upper ring. For example, the second predetermined inner diameter D2 is greater than the first predetermined inner diameter D1 , and the fourth predetermined inner diameter of the fourth ring 44 may be greater than the third predetermined inner diameter of the third ring 43 .

[0058] By configuring the inner peripheral wall 401 of the ring 4, the device 100 for controlling the diameter of the growing crystal can control the diameter of the crystal 300 when manufacturing the crystal 300. When the crystal 300 grows, its periphery is limited by the inner peripheral wall 401, and can only be formed according to the internal shape of the ring 4, and the size is realized as a predetermined size. The crystal 300 can be divided into multiple intervals along the Z-axis direction, and the growth diameter of each interval can be controlled by the device 100 for controlling the diameter of the growing crystal. According to the different configuration states of the control ring assembly 3, the device 100 for controlling the diameter of the growing crystal can be used to form crystals 300 of multiple predetermined diameters.

[0059] The predetermined inner diameter can be used to easily distinguish different rings 4. For a designed ring 4, in addition to the predetermined inner diameter, the dimensions at different height positions are also known. When necessary, a ring 4 can be selected to manufacture a specified crystal 300, and then a wafer can be obtained by, for example, cutting.

[0060] The device 100 for controlling the diameter of a growing crystal according to the embodiment of the present disclosure is easy to use, reduces processing steps, and has controllable costs.

[0061] In some embodiments, the inner circumferential wall 401 of each ring 4 of the plurality of rings 4 gradually expands from top to bottom. The cross section of the ring 4 may be annular, such as a circular ring; and the space enclosed by the inner circumferential wall 401 may be truncated cone-shaped. Figure 5 and Figure 8 , the lower end of the inner circumferential wall 401 of the ring 4 has a predetermined inner diameter. The space in each ring 4 is suitable for forming a crystal 300. The lower inner diameter of the upper ring is close to the upper inner diameter of the lower ring, which is conducive to the transition between multiple rings 4 and is conducive to manufacturing crystals 300 with different predetermined diameters at different positions. For example, the first predetermined inner diameter D1 of the inner circumferential wall 401 of the first ring 41 is the same as the upper inner diameter of the inner circumferential wall 401 of the second ring 42.

[0062] In some embodiments, the inner circumferential wall 401 of the ring 4 is a conical surface, and the outer circumferential wall 402 of the ring 4 is a conical surface. The wall thickness of the ring 4 can be thinner, and then the weight is lighter, and it is easier to control the temperature when in use. The inner circumferential wall 401 is substantially parallel to the outer circumferential wall 402, and a substantially equal thickness is achieved. The upper end face 403 or the lower end face 404 of the ring 4 is used to dock with another corresponding ring 4, for example, the upper end face 403 of the second ring 42 is used to dock with the lower end face 404 of the first ring 41, and the lower end face 404 of the second ring 42 is used to dock with the upper end face 403 of the third ring 43. Optionally, the heights of different rings 4 can be different, and the slopes of the inner circumferential wall 401 can also be different.

[0063] refer to Figure 3 , two adjacent rings 4 are connected by screws (not shown). In some embodiments, for two adjacent rings 4, the screws extend from the outer peripheral wall 402 of the upper ring through the lower end face 404 of the upper ring and the upper end face 403 of the lower ring into the lower ring. Exemplarily, the lower portion of the first ring 41 may have a first screw hole 405, and the upper end of the second ring 42 may be provided with a third screw hole 407. The screws may be inserted into the first screw hole 405 and the third screw hole 407 to connect the first ring 41 with the second ring 42. Since the outer peripheral wall 402 is inclined relative to the lower end face 404, an operating space is provided, and the screws can be easily operated from the outside of the ring 4 to connect the two adjacent rings 4. The installation position of the screws matches the shape of the ring 4, so that the connection structure is simple and durable.

[0064] The screw and the third screw hole 407 can be threadedly connected; the screw and the first screw hole 405 can also be threadedly connected. The upper part of the first screw hole 405 may not be countersunk to ensure the length of the first screw hole 405, and the ring 4 has a thinner wall. The third screw hole 407 can be terminated in the ring 4, for example Figure 8 As shown, the upper end surface 403 of the second ring 42 is provided with a third screw hole 407, and the third screw hole 407 does not penetrate the inner peripheral wall 401. Figure 1 and Figure 3 As shown, the inner wall of the control ring assembly 3 can be relatively complete, which is conducive to taking the crystal 300 out of the control ring assembly 3 and is conducive to manufacturing the crystal 300 of good quality.

[0065] For example, the first screw hole 405 may extend along the Z axis. The ring 4 may be provided with two first screw holes 405 along the circumferential direction, or may be provided with a greater number of first screw holes 405, such as four first screw holes 405, and these first screw holes 405 may be evenly distributed along the XY plane. Figure 4 The first ring 41 may have two first screw holes 405 arranged on both sides of the inner peripheral wall 401 along the X-axis direction.

[0066] Combination Figure 3 , Figure 7 and Figure 8 , the second ring 42 may be provided with other first screw holes 405 for connecting the third ring 43. Figure 2 and Figure 3 The lowest ring 4 among the multiple rings 4, such as the fourth ring 44, may not be provided with the first screw hole 405.

[0067] In some embodiments, the outer periphery of the seed rod 1 is connected to the corresponding ring 4, namely the first ring 41, by screws. The upper portion of the first ring 41 may be provided with a second screw hole 406. Figures 2 to 6 The first ring 41 may be provided with two second screw holes 406, which are arranged opposite to each other along the X-axis direction and respectively penetrate the body of the first ring 41. Correspondingly, the outer periphery of the seed crystal rod 1 is provided with at least two threaded holes opposite to each other along the second direction, and the connection structure is simple and can balance the force, thereby ensuring that the control ring assembly 3 is reliably connected to the seed crystal rod 1.

[0068] In some embodiments, the material of the ring 4 is boron nitride, which can avoid the introduction of impurities when manufacturing silicon carbide crystals. The ring 4 made of boron nitride can be connected by screws, which is easy to assemble while ensuring strength. The material of the seed rod 1 can be graphite. The second screw hole 406 can extend along the X-axis direction and can be a threaded hole.

[0069] In some embodiments, the predetermined inner diameter of the ring 4 connected to the seed crystal rod 1 is 2 inches, and the predetermined inner diameter of each ring is successively increased by 0.5 inches compared with the previous ring. The device 100 for controlling the diameter of the growing crystal can be used to manufacture crystals 300 having predetermined diameters of 2 inches, 2.5 inches, 3 inches, etc. at different positions, which can meet the crystal manufacturing requirements. Exemplarily, the first predetermined inner diameter D1 of the first ring 41 is 2 inches, the second predetermined inner diameter D2 of the second ring 42 is 2.5 inches, the third predetermined inner diameter of the third ring 43 is 3 inches, and the fourth predetermined inner diameter of the fourth ring 44 is 3.5 inches.

[0070] refer to Fig. 9 and Fig.10 In some embodiments, the device 100 for controlling the diameter of the growing crystal further comprises a plurality of chamfer rings 40. The chamfer rings 40 are detachably connected to the lower portion of the corresponding ring 4. The arc chamfer 408 of the chamfer ring 40 is bent inward relative to the inner peripheral wall 401 of the ring 4. It can be understood that the chamfer ring 40 corresponding to the first ring 41 is different in size from the chamfer ring 40 corresponding to the second ring 42.

[0071] refer to Fig. 9 , illustratively, the chamfered ring 40 can be connected to the lower end of the ring 4. When in use, the chamfered ring 40 can be installed on the lowermost ring 4.

[0072] refer to Fig.10 , wherein two halves of the figure at different angles are rotated and cut away, and the chamfered ring 40 can be connected to the inner peripheral wall 401 of the ring 4. When in use, the chamfered ring 40 can be installed on the lowermost ring 4.

[0073] refer to Fig.11 , Fig.11 Shown based on Fig. 9 or Fig.10 The crystal 300 manufactured by the device 100 for controlling the diameter of a growing crystal in the illustrated embodiment has a size that meets the use requirements, is not prone to cracking at the edge, and has good surface quality.

[0074] like Figure 1 As shown, the device 100 for controlling the diameter of the growing crystal further includes a crucible 5, which is used to accommodate the control ring assembly 3 and at least a portion of the seed crystal rod 1. The device 100 for controlling the diameter of the growing crystal can be used for liquid phase method to manufacture the crystal 300. The crucible 5 may include a crucible cover (not shown) with holes.

[0075] In some embodiments, the device 100 for controlling the diameter of the growing crystal further includes a heat-insulating outer liner 6 and a heater 7, wherein the heat-insulating outer liner 6 surrounds the crucible 5 and the heater 7 is located outside the heat-insulating outer liner 6. The seed crystal rod 1 can be raised and lowered relative to the crucible 5 along a first direction; the material of the crucible 5 is graphite. The device 100 for controlling the diameter of the growing crystal can be used to manufacture silicon carbide crystals by a liquid phase method. Exemplarily, the seed crystal rod 1 can rotate relative to the crucible 5 around an axis.

[0076] refer to Fig.12 The embodiment of the present disclosure provides a method 1000 for controlling the diameter of a growing crystal, which can be implemented using the aforementioned device 100 for controlling the diameter of a growing crystal. The method 1000 includes step S110, manufacturing a crystal 300 with a predetermined diameter by a liquid phase method.

[0077] Combination Figure 1As shown, in a comparative example, a crystal is manufactured in a crucible 5 using a seed crystal rod 1 and a seed crystal 2. The diameter of the manufactured crystal is difficult to control accurately, and needs to be larger and then cut into smaller suitable sizes.

[0078] Based on the device 100 for controlling the diameter of a growing crystal, when manufacturing a crystal 300 by liquid phase method, the control ring assembly 3 can be connected to the seed rod 1. The control ring assembly 3 is configured with a suitable number of rings 4 according to a predetermined size, for example, only the first ring 41 is connected.

[0079] In addition, silicon powder is added to the crucible 5 made of graphite material and heated to melt the silicon powder. The carbon in the crucible 5 can be dissolved to obtain a solution 200.

[0080] During the growth process, the seed crystal 2 is immersed in the solution 200 through the seed crystal rod 1, which will reduce the temperature of the solution around the seed crystal 2. The silicon carbide solution around the seed crystal 2 is in a supersaturated state, and silicon carbide begins to grow epitaxially. Since the first ring 41 is sleeved on the seed crystal 2, a length interval is defined along the Z-axis direction, which can be called the first interval. When the crystal 300 in the first interval grows to a first predetermined size, such as 2 inches, the side of the crystal 300 in this interval is separated from the solution 200 by the corresponding ring 4, and the crystal 300 in this interval cannot continue to expand. In this way, a 2-inch crystal 300 with precise diameter size, free of cracking and good quality is obtained.

[0081] Exemplarily, in order to obtain crystals 300 of more sizes or larger sizes, a control ring assembly 3 including a plurality of rings 4 may be used to manufacture the crystal 300. Exemplarily, in order to grow a 2.5-inch crystal, the second ring 42 is connected to the first ring 41. The control ring assembly 3 may be used to form a crystal column, which is an integral structure and may be subsequently cut or sliced. A section of the structure within different intervals of the crystal column may be regarded as a different crystal 300 to be separated; on the other hand, the crystal column may also be referred to as a crystal 300. When forming a crystal column, a 2.5-inch crystal 300 may be formed under a 2-inch crystal 300.

[0082] In order to grow a 3-inch crystal, the third ring 43 is connected to the second ring 42. By controlling the ring assembly 3, when forming a crystal column, a 3-inch crystal 300 can be formed under a 2.5-inch crystal 300.

[0083] In order to grow a 3.5-inch crystal, the fourth ring 44 is connected to the third ring 43. By using the control ring assembly 3, when forming a crystal column, a 3.5-inch crystal 300 can be formed under a 3-inch crystal 300.

[0084] The method 1000 for controlling the diameter of a growing crystal according to the embodiment of the present disclosure is easy to perform and can control the diameter of the crystal 300 to form crystals 300 of various predetermined diameters. In addition, the edge state of the crystal 300 formed by the method 1000 is good.

[0085] Exemplarily, the method 1000 for controlling the diameter of the growing crystal further includes step S120: cutting the crystal 300. The crystal 300 has different diameters at different positions along the Z-axis direction. Multiple wafers with different diameters can be obtained by cutting. Exemplarily, it is not necessary to cut the periphery of the wafer.

[0086] The embodiment of the present disclosure provides a crystal 300, which is a silicon carbide crystal. The silicon carbide crystal is manufactured according to the steps of the aforementioned method 1000 for controlling the diameter of a growing crystal. The manufacturing cost of the silicon carbide crystal is low and waste is small; because the ring 4 avoids problems such as peripheral cracking, the quality of the crystal 300 is good.

[0087] The technical features of the embodiments disclosed above can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] In the embodiments disclosed above, unless otherwise clearly specified and limited, the execution order of each step is not limited, for example, it can be executed in parallel, or it can be executed successively in different orders. The sub-steps of each step can also be executed alternately. The above-mentioned various forms of processes can be used, and steps can be reordered, added or deleted, as long as the desired results of the technical solution provided in the embodiment of the present disclosure can be achieved, and this document does not limit it here.

[0089] The embodiments disclosed above only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of patent protection required by the present application. Therefore, the scope of patent protection of the present application shall be subject to the attached claims.

Claims

1. A device for controlling the diameter of a growing crystal, characterized in that: include: A seed crystal rod, wherein the lower end surface of the seed crystal rod along the first direction is used for setting the seed crystal; and A control ring assembly, the control ring assembly includes a plurality of rings detachably connected in sequence along the first direction, the inner circumferential wall of each ring having a predetermined inner diameter; among two adjacent rings, the predetermined inner diameter of the lower ring is greater than the predetermined inner diameter of the upper ring; among the plurality of rings, the ring connected to the seed crystal rod is sleeved on the seed crystal rod and sleeved on the seed crystal.

2. The device for controlling the diameter of a growing crystal according to claim 1, wherein: The inner circumferential wall of each of the plurality of rings gradually expands from top to bottom, and the lower end of the inner circumferential wall of the ring has the predetermined inner diameter.

3. The device for controlling the diameter of a growing crystal according to claim 2, wherein: It also includes a plurality of chamfered rings, which are detachably connected to the lower part of the corresponding ring, and the arc-shaped chamfers of the chamfered rings are bent inwardly relative to the inner peripheral wall of the ring.

4. The device for controlling the diameter of a growing crystal according to claim 2, wherein: The inner circumferential wall of the ring is a conical surface, and the outer circumferential wall of the ring is a conical surface; the upper end surface or the lower end surface of the ring is used to dock with another corresponding ring, and two adjacent rings are connected by screws; In two adjacent rings, the screw extends from the outer peripheral wall of the upper ring through the lower end surface of the upper ring and the upper end surface of the lower ring and into the lower ring.

5. The device for controlling the diameter of a growing crystal according to claim 1, wherein: The outer periphery of the seed crystal rod is connected to the corresponding ring through screws, and the outer periphery of the seed crystal rod is provided with at least two threaded holes opposite to each other along the second direction.

6. The device for controlling the diameter of a growing crystal according to claim 4 or 5, wherein: The material of the ring is boron nitride.

7. The device for controlling the diameter of a growing crystal according to claim 1, wherein: The predetermined inner diameter of the ring connected to the seed rod is 2 inches, and the predetermined inner diameter of each ring increases by 0.5 inches compared with the previous ring.

8. The device for controlling the diameter of a growing crystal according to claim 1, wherein: Also includes a crucible, a heat-insulating outer lining and a heater, wherein the crucible is used to accommodate the control ring assembly and at least a portion of the seed rod; The heat-insulating outer lining surrounds the crucible, and the heater is located at the outer periphery of the heat-insulating outer lining; The seed crystal rod can be lifted and lowered relative to the crucible along the first direction; the material of the crucible is graphite.

9. A method for controlling the diameter of a growing crystal, characterized in that Using the apparatus for controlling the diameter of a growing crystal as claimed in any one of claims 1 to 8, a crystal having a predetermined diameter is produced by a liquid phase method.

10. Silicon carbide crystal, characterized in that The method for controlling the diameter of a growing crystal is manufactured according to claim 9.

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