CN116180218A - Crystal preparation device - Google Patents

Abstract

Embodiments of the present specification provide a crystal preparation apparatus for preparing crystals by a liquid phase method, the apparatus comprising: the growth cavity is internally provided with at least one layer of plate assembly, wherein the at least one layer of plate assembly comprises a through hole; for at least one of the at least one plate assembly, the ratio of the sum of the opening areas of the through holes to the upper surface area of the plate assembly is in the range of 30% -80%; the heating component is used for heating the growth cavity; the connecting assembly is used for connecting the seed crystal support to support the seed crystal; and the power assembly is used for driving the connecting assembly to rotate and/or move up and down so as to drive the seed crystal holder to rotate and/or move up and down.

Description

Crystal preparation device

Description of the division

The present application is a divisional application filed in China with the name of "a seed crystal preparation device" and having the application date of 2022, month 06 and 07, the application number of 202210632655.5.

Technical Field

The specification relates to the technical field of crystal preparation, in particular to a device for preparing crystals based on a liquid phase method.

Background

In preparing crystals (e.g., silicon carbide) based on liquid phase methods (e.g., liquid phase epitaxy (liquid phase epitaxy, LPE)), the volatile components of the feedstock may move upward and even evaporate to a gaseous state and continue to overflow to external insulation components, causing excessive consumption of the feedstock, and the volatilization process may cause deviations in the components of the feedstock, affecting crystal growth. In addition, the spilled vapor can affect the insulation performance of the insulation assembly. Therefore, it is necessary to provide a crystal preparation device, which improves the movement condition of volatile components and further ensures the normal growth of crystals.

Disclosure of Invention

One of the embodiments of the present specification provides a crystal preparation apparatus for preparing crystals by a liquid phase method, the apparatus comprising: the growth chamber is internally provided with at least one layer of plate assembly, wherein the at least one layer of plate assembly comprises a through hole; a heating assembly for heating the growth chamber; the connecting assembly is used for connecting the seed crystal support to support the seed crystal; and the power assembly is used for driving the connecting assembly to rotate and/or move up and down so as to drive the seed crystal holder to rotate and/or move up and down.

In some embodiments, the through holes of adjacent plate assemblies are staggered with respect to each other.

In some embodiments, for at least one of the at least one plate assembly, the ratio of the sum of the opening areas of the through holes to the upper surface area of the plate assembly is in the range of 30% -80%.

In some embodiments, the density of the through holes decreases gradually from the center to the edge of the plate assembly.

In some embodiments, the ratio of the density of through holes near the center of the plate assembly to the density of through holes near the edges of the plate assembly is in the range of 1:1-20:1.

In some embodiments, the diameter of the through hole is in the range of 0.1mm-10 mm.

In some embodiments, the upper predetermined extent of the growth chamber sidewall is coated or provided with a shielding ring.

In some embodiments, the device further comprises a cavity cover and an upper heat preservation component, and a gap between the cavity cover and the upper heat preservation component is filled with carbon powder.

In some embodiments, the cavity cover includes a raised structure.

In some embodiments, the wall thickness of the growth chamber sidewall increases gradually in a top-to-bottom direction of the growth chamber.

Drawings

The present specification will be further elucidated by way of example embodiments, which will be described in detail by means of the accompanying drawings. The embodiments are not limiting, in which like numerals represent like structures, wherein:

FIG. 1 is a schematic diagram of an exemplary crystal production apparatus according to some embodiments of the present disclosure;

FIG. 2 is a schematic view of a through hole in an exemplary plate assembly shown according to some embodiments of the present disclosure;

FIG. 3 is a schematic view of a through hole in an exemplary plate assembly shown according to some embodiments of the present disclosure;

FIG. 4 is a schematic partial structural view of an exemplary cavity cover and upper insulating member shown in accordance with some embodiments of the present description;

Fig. 5 is a schematic diagram of an exemplary growth chamber shown in accordance with some embodiments of the present disclosure;

FIG. 6 is a schematic diagram of an exemplary seed holder and seed crystal according to some embodiments of the present disclosure;

FIG. 7 is a flow chart of an exemplary crystal preparation method according to some embodiments of the present description.

In the figure, 100 is a crystal preparation device, 110 is a growth cavity, 120 is a heating component, 111 is a plate component, 1111 is a through hole, 130 is a cavity cover, 131 is a gap, 132 is a convex structure, 140 is a heat insulation component, 141 is an upper heat insulation component, 142 is a middle heat insulation component, 143 is a cavity bottom heat insulation component, 144 is a lower heat insulation component, 150 is a seed crystal support, 160 is a connecting component, 170 is a cover plate, 180 is a seed crystal, 181 is a first seed crystal, 182 is a second seed crystal, and 190 is graphite paper.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present specification, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present specification, and it is possible for those of ordinary skill in the art to apply the present specification to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.

It will be appreciated that "system," "apparatus," "unit" and/or "module" as used herein is one method for distinguishing between different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

As used in this specification and the claims, the terms "a," "an," "the," and/or "the" are not specific to a singular, but may include a plurality, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.

FIG. 1 is a schematic diagram of an exemplary crystal production apparatus according to some embodiments of the present disclosure.

In some embodiments, crystal production apparatus 100 may be based on a liquid phase process to produce crystals (e.g., silicon carbide). The crystal production apparatus 100 according to the embodiment in the specification will be described in detail below with reference to the accompanying drawings, taking as an example the production of silicon carbide crystals. It is noted that the following examples are merely illustrative of the present specification and are not to be construed as limiting the present application.

As shown in fig. 1, crystal preparation apparatus 100 may include a growth chamber 110 and a heating assembly 120.

The growth chamber 110 serves as a place for crystal preparation, and the heating assembly 120 is used to heat the growth chamber 110 to provide the heat (e.g., temperature field, etc.) required for crystal preparation.

In some embodiments, the material of the growth chamber 110 may be determined according to the type of crystal to be prepared. For example, in preparing silicon carbide crystals, the material of growth chamber 110 may include graphite. In some embodiments, the material of the growth chamber 110 may also include molybdenum, tungsten, tantalum, and the like. In some embodiments, the growth chamber 110 may provide the raw materials needed to produce the crystal. For example, growth chamber 110 may serve as a carbon source to provide the carbon needed to produce silicon carbide crystals. In some embodiments, raw materials (e.g., silicon powder, carbon powder) required to prepare crystals may be placed within growth chamber 110. In some embodiments, growth chamber 110 may be where the raw materials form a melt. For example, under the high temperature generated by heating assembly 120, the silicon powder melts into a melt (liquid state), and the carbon provided by growth chamber 110 itself dissolves in the silicon solution to form a solution of carbon in silicon as a liquid feedstock for the liquid phase process for preparing silicon carbide crystals. In some embodiments, to increase the solubility of carbon in silicon, fluxing agents (e.g., aluminum, silicon chromium alloys, li-Si alloys, ti-Si alloys, fe-Si alloys, sc-Si alloys, co-Si alloys, etc.) may be added to the raw materials.

In some embodiments, the upper predetermined area of the inner sidewall of growth chamber 110 may be coated or a shield ring may be provided to prevent spontaneous nucleation and crystal growth by reaction of silicon near the melt surface with carbon of the growth chamber 110 sidewall. In some embodiments, the material of the coating or shielding ring may be a refractory metal (e.g., rare earth metals such as tungsten, tantalum, molybdenum, chromium, aluminum) or a metal compound (e.g., zirconia, alumina, etc.).

In some embodiments, the upper preset range may be in the range of 0-2/3 of the height of the growth chamber. In some embodiments, the upper preset range may be in the range of 0-1/3 of the height of the growth chamber. In some embodiments, the upper preset range may be in the range of 0-1/4 of the height of the growth chamber.

For further description of growth chamber 110, reference may be made to other portions of this specification (e.g., fig. 5 and its description), which are not repeated here.

In some embodiments, the heating assembly 120 may include an induction heating assembly, a resistance heating assembly, or the like. In some embodiments, the heating assembly 120 may be disposed around the periphery of the growth chamber 110.

In some embodiments, the heating assembly 120 may include an induction coil. In some embodiments, an induction coil may be disposed around the outer perimeter of growth chamber 110. In some embodiments, to ensure the desired temperature field for crystal growth, and to increase the crystal growth efficiency, the height ratio of the growth chamber 110 to the induction coil needs to be within a predetermined range.

In some embodiments, the height ratio of growth chamber 110 to induction coil may be in the range of 1:1-1:5. In some embodiments, the height ratio of the growth chamber 110 to the induction coil may be in the range of 1:1.5-1:4.5. In some embodiments, the height ratio of growth chamber 110 to induction coil may be in the range of 1:2-1:4. In some embodiments, the height ratio of the growth chamber 110 to the induction coil may be in the range of 1:2.5-1:3.5. In some embodiments, the height ratio of the growth chamber 110 to the induction coil may be in the range of 1:2.8-1:3.

In some embodiments, at least one lamina assembly 111 may be disposed within growth chamber 110. In some embodiments, the plate assembly 111 may be located within a melt within the growth chamber 110.

When growing silicon carbide crystals, convection occurs in the melt within growth chamber 110, and silicon moves upward from the bottom of growth chamber 110, and even evaporates from a liquid state to a gaseous state, continuing to overflow, causing excessive consumption of silicon. In addition, the overflowed silicon vapor may overflow the growth chamber 110 and adhere to the insulation components outside the chamber, causing pollution to the insulation components, affecting the insulation performance. Accordingly, at least one plate assembly 111 disposed within the growth chamber may change the convection of the melt, slow the upward movement of the silicon, avoid excessive consumption, and simultaneously avoid or reduce the amount of silicon vapor escaping outside the chamber, and avoid or reduce contamination of the insulating assembly.

In some embodiments, the material of the plate member 111 may be determined according to the kind of crystal to be prepared. For example, in preparing silicon carbide crystals, the plate member 111 is the same material as the growth chamber 110 (e.g., graphite). Graphite can be used as a carbon source to provide carbon required for preparing silicon carbide crystals, and can also react with silicon to generate silicon carbide, accordingly, the consumption of the growth chamber 110 can be reduced, and the number of times of use of the growth chamber 110 can be further increased.

In some embodiments, the plate assembly 111 may include a through hole therein. The through holes may act as channels for convection or movement of the melt. In some embodiments, the design of the via holes is required to meet preset conditions in order to slow the upward movement of silicon while meeting the convection or movement requirements. Further description can be seen in fig. 2 and 3, and no further description is given here.

In some embodiments, when heating assembly 120 is an induction heating assembly (as shown in fig. 1), plate assembly 111 may also act as a heat source to provide the heat required for crystal preparation (e.g., the thermal energy required for dissolution of the feedstock into the melt for crystal growth, the temperature field required for crystal growth).

In some embodiments, the plate assembly 111 (e.g., uppermost plate assembly) may be located a preset distance below the melt level. In some embodiments, the distance that plate assembly 111 (e.g., the uppermost plate assembly) is below the melt level can affect the passage, path, etc. of melt feedstock to the crystal growth surface required for crystal growth, thereby affecting the quality of the grown crystal. Therefore, the preset distance needs to be within a preset range.

In some embodiments, the preset distance may be in the range of 10mm-50 mm. In some embodiments, the preset distance may be in the range of 15mm-45 mm. In some embodiments, the preset distance may be in the range of 20mm-40 mm. In some embodiments, the preset distance may be in the range of 25mm-35 mm. In some embodiments, the preset distance may be in the range of 28mm-32 mm.

In some embodiments, to improve stability of crystal growth, the plate assembly 111 (e.g., the lowermost plate assembly) may be located near the midpoint of the melt or heating assembly (e.g., induction coil) height. In some embodiments, nearby may refer to within a preset distance. In some embodiments, the predetermined distance may include + -50 cm, + -40 cm, + -30 cm, + -20 cm, + -10 cm, + -8 cm, + -6 cm, + -4 cm, + -2 cm, + -1 cm, and the like. For example, the vicinity of the midpoint of the melt height may be included within + -30 cm of 1/2 of the melt height.

In some embodiments, the spacing between adjacent plate assemblies 111 may affect the temperature field near the crystal growth interface, the supply of raw materials (e.g., carbon, silicon) required for growth, their path to the crystal growth interface, and so forth. Therefore, the interval between the adjacent plate assemblies 111 needs to be within a preset range.

In some embodiments, the spacing between adjacent plate assemblies 111 may be in the range of 10mm-60 mm. In some embodiments, the spacing between adjacent plate assemblies 111 may be in the range of 15mm-55 mm. In some embodiments, the spacing between adjacent plate assemblies 111 may be in the range of 20mm-50 mm. In some embodiments, the spacing between adjacent plate assemblies 111 may be in the range of 25mm-45 mm. In some embodiments, the spacing between adjacent plate assemblies 111 may be in the range of 30mm-40 mm. In some embodiments, the spacing between adjacent plate assemblies 111 may be in the range of 34mm-36 mm.

In some embodiments, crystal production apparatus 100 may further comprise a cavity cover 130. In some embodiments, the cavity cover 130 may be shaped and sized to mate with the growth cavity 110. In some embodiments, the chamber lid 130 and the growth chamber 110 may be sealingly connected or detachably connected (e.g., snapped in).

In some embodiments, crystal production apparatus 100 may further comprise a soak assembly 140 for holding growth chamber 110. In some embodiments, the insulating member 140 may be disposed around the outer circumference of the growth chamber 110. In some embodiments, the insulating assembly 140 may be disposed around the exterior of the heating assembly 120.

In some embodiments, the insulation assembly 140 may include an upper insulation member 141, a middle insulation member 142, a cavity floor insulation member 143, and a lower insulation member 144.

In some embodiments, as shown in FIG. 1, an upper insulating member 141 may be located at an upper portion of the growth chamber 110. In some embodiments, the middle insulating member 142 may be located below the lower or upper insulating member 141 of the growth chamber 110. In some embodiments, the chamber bottom insulating member 143 may be located at the bottom of the growth chamber 110. In some embodiments, the lower insulating member 144 may be located below the middle insulating member 142 and the bottom insulating member 143. In some embodiments, the adjacent insulation members (e.g., upper insulation member 141 and middle insulation member 142, middle insulation member 142 and lower insulation member 144, cavity floor insulation member 143 and lower insulation member 144) may be detachably connected (e.g., snap-fit connected) to facilitate removal and replacement of the damaged insulation members.

In some embodiments, the thermal insulation components (e.g., upper thermal insulation component 141, middle thermal insulation component 142, bottom thermal insulation component 143, lower thermal insulation component 144) may include bulk thermal insulation, granular thermal insulation, floc thermal insulation, lamellar thermal insulation, and the like. In some embodiments, the material of each insulating component may include quartz (silica), corundum (alumina), zirconia, carbon fiber, ceramic, etc., or other refractory materials (e.g., boride, carbide, nitride, silicide, phosphide, sulfide, etc. of rare earth metals). In some embodiments, the materials of the thermal insulation components may be the same or different.

In some embodiments, crystal production apparatus 100 may further include a seed holder 150 for holding a seed crystal. In some embodiments, the material of the seed holder 150 may include graphite. For a description of the seed holder 150 and the seed crystal, reference may be made to other portions of the present specification (e.g., fig. 6 and the description thereof), and a detailed description thereof will be omitted.

In some embodiments, crystal production apparatus 100 may further include a connection assembly 160 for connecting to seed holder 150. In some embodiments, the connection assembly 160 may be a cylinder, a pyramid, or the like. In some embodiments, the connection assembly 160 may be integrally formed or formed by connecting a plurality of connection members to one another. In some embodiments, the material of the connection component 160 may include, but is not limited to, graphite, and the like.

In some embodiments, crystal growing apparatus 100 may further comprise a power assembly (not shown) for rotating and/or moving up and down connecting assembly 160 to rotate and/or move up and down seed holder 150 to grow the crystal.

In some embodiments, crystal production apparatus 100 may further include a cover plate 170. In some embodiments, the cover plate 170 may be used to reduce crystal cracking. In some embodiments, the cover plate 170 may be located above the upper insulating member 141. In some embodiments, the cover 170 may be a cylinder, pyramid, or the like. In some embodiments, the material of the cover 170 may be the same as or different from the material of the thermal insulation component 140.

In some embodiments, as shown in FIG. 1, the chamber lid 130, the upper insulating member 141, and the cover plate 170 are provided with holes therethrough to allow the connection assembly 160 and the seed holder 150 to pass therethrough for rotation and/or up-and-down movement.

In some embodiments, the size of the holes in the cover plate 170 can affect the amount of silicon evaporation. For example, the size of the holes is too large, heat may be dissipated from the holes, resulting in an increase in the thermal energy that needs to be provided by the heating assembly, which in turn results in an increase in the melt temperature and an increase in silicon volatilization. And too small a size of the hole in the cover plate 170 may result in the connection assembly 160 and the seed holder 150 not passing through to rotate and/or move up and down, thereby failing to grow the crystal normally. Therefore, the diameter of the hole in the cover plate 170 is required to be within a predetermined range.

In some embodiments, the diameter of the aperture in the cover plate 170 may be in the range of 20mm-150 mm. In some embodiments, the diameter of the aperture in the cover plate 170 may be in the range of 40mm-120 mm. In some embodiments, the diameter of the aperture in the cover plate 170 may be in the range of 50mm-100 mm. In some embodiments, the diameter of the aperture in the cover plate 170 may be in the range of 70mm-80 mm.

It should be noted that the above description of crystal production apparatus 100 is for illustration and description only, and does not limit the scope of application of the present application. Various modifications and variations of crystal production apparatus 100 may be made by those skilled in the art under the guidance of this application. However, such modifications and variations are still within the scope of the present application.

Fig. 2 is a schematic view of a through hole in an exemplary plate assembly shown in accordance with some embodiments of the present description. Fig. 3 is a schematic view of a through hole in an exemplary plate assembly shown according to some embodiments of the present description.

In some embodiments, as shown in fig. 2 and 3, the plate assembly 111 may include a through hole 1111 therein. In some embodiments, the through holes 1111 may extend through the board assembly 111. In some embodiments, the shape of the through holes 1111 may include regular or irregular shapes such as circles, ovals, polygons, stars, and the like. In some embodiments, the shape of the through holes 1111 on one plate assembly 111 may be the same or different. In some embodiments, the shape of the through holes 1111 on different plate assemblies 111 may be the same or different.

In some embodiments, the through holes 1111 on adjacent plate assemblies 111 may be staggered with respect to each other. For example, as shown in fig. 2, the through hole 1111 (shown in solid line portion in fig. 2) on the upper board assembly does not coincide with the through hole 1111' (shown in broken line portion in fig. 2) on the lower board assembly. In some embodiments, interdigitating may mean not overlapping or partially overlapping each other.

Through the mutual staggered design of the through holes 1111 on the adjacent plate assemblies 111, the convection of the melt in the growth cavity 110 can be regulated, the rising speed of volatile components (for example, silicon) can be reduced, the volatilization amount of the volatile components (for example, silicon) on the surface of the melt can be reduced, silicon carbide particles generated by the reaction of the volatile components (for example, silicon vapor) and graphite of the growth cavity 110 can be reduced, pollution or damage to the heat insulation assembly caused by the attachment of the volatile silicon or the generated silicon carbide particles to the upper heat insulation part can be further reduced, the heat insulation performance of the heat insulation assembly can be ensured, and the normal growth of crystals can be further ensured.

The ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate member 111 in which the through holes 1111 are located affects the convection of the melt in the growth chamber 110, thereby affecting the normal growth of the crystal. For example, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate member 111 where the through holes 1111 are located is too large to effectively improve the silicon rising speed, and accordingly, to effectively reduce the volatilization of silicon on the melt surface. For another example, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate member 111 where the through holes 1111 are located is too small, the resistance to upward movement of the melt increases, and it is not ensured that a sufficient amount of the melt can move to the vicinity of the seed crystal, thereby affecting the crystal growth rate. Thus, in some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the board assembly 111 where the through holes 1111 are located is required to satisfy the predetermined requirement.

In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 may be in the range of 30% -80% for at least one of the at least one plate assembly 111. In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 may be in the range of 35% -75% for at least one of the at least one plate assembly 111. In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 may be in the range of 40% -70% for at least one of the at least one plate assembly 111. In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 may be in the range of 45% -65% for at least one of the at least one plate assembly 111. In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 may be in the range of 50% -60% for at least one of the at least one plate assembly 111. In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 may be in the range of 52% -58% for at least one of the at least one plate assembly 111. In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 may be in the range of 54% -56% for at least one of the at least one plate assembly 111.

In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 in which the through holes 1111 are located may be the same or different for different plate assemblies 111. In some embodiments, the ratio of the sum of the opening areas of the through holes 1111 to the upper surface area of the plate assembly 111 where the through holes 1111 are located may be gradually decreased or increased in the direction from the bottom of the growth chamber 110 to the top of the growth chamber 110. For example, as shown in fig. 2, the ratio of the sum of the opening areas of the through holes 1111 (shown in solid line portion in fig. 2) on the upper plate member to the upper surface area of the plate member may be smaller than the ratio of the sum of the opening areas of the through holes 1111' (shown in broken line portion in fig. 2) on the lower plate member to the upper surface area of the plate member.

In some embodiments, as shown in fig. 3, the density of through holes 1111 (e.g., the number of through holes 1111 per unit area) may gradually decrease from the center to the edge of the board assembly 111. In some embodiments, the density of through holes near the center of the plate assembly 111 may be higher than the density of through holes near the edges of the Yu Ban assembly 111. Accordingly, it is ensured that a sufficient amount of melt can move upward from the through hole 1111 located near the center of the plate member 111 to the seed crystal to crystallize and grow a crystal, and crystal preparation efficiency is ensured while improving the melt convection condition and thus the excessive consumption of silicon.

In this embodiment, "near" may refer to within a predetermined distance. In some embodiments, the preset distance may include 10cm, 8cm, 6cm, 4cm, 2cm, 1cm, etc. In some embodiments, the "near center" of the plate assembly 111 may refer to an area of the plate assembly centered at the center of the plate assembly 111 and having a radius of a predetermined distance. In some embodiments, the "near edge" of the plate assembly 111 may refer to an area of the plate assembly within a predetermined distance from the edge of the plate assembly 111.

Too small a ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 can result in a greater natural nucleation or natural nucleation rate of silicon carbide on the inner walls of the growth chamber 110, while too large a ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 can result in too fast growth of the crystal centers and susceptibility to formation of parcels and cracking. Thus, in some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 is within a predetermined range.

In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-20:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-18:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-16:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-14:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-12:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-10:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-8:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-6:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1:1-5:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 1.5:1-4.5:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 2:1-4:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 2.5:1-3.5:1. In some embodiments, the ratio of the density of through holes near the center of the plate assembly 111 to the density of through holes near the edges of the plate assembly 111 may be in the range of 2.8:1-3.2:1.

The diameter of the through holes 1111 may affect the convection of the melt within the growth chamber 110, which in turn may affect the proper growth of the crystal. For example, the diameter of the through holes 1111 is too large to effectively improve the silicon rising speed and accordingly to effectively reduce the volatilization of silicon on the melt surface. For another example, the diameter of the through hole 1111 is too small, and the resistance to upward movement of the melt increases, so that it is not guaranteed that a sufficient amount of melt can move to the vicinity of the seed crystal, thereby affecting the crystal growth rate. Thus, in some embodiments, the diameter of the through-hole 1111 needs to meet a preset requirement.

In some embodiments, the diameter of the through holes 1111 may be in the range of 0.1mm-10 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 0.1mm-9 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 0.1mm-8 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 0.1mm-7 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 0.1mm-6 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 0.1mm-5 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 0.1mm-5 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 0.5mm-4.5 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 1mm-4 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 1.5mm-3.5 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 2mm-3 mm. In some embodiments, the diameter of the through holes 1111 may be in the range of 2.4mm-2.6 mm.

Fig. 4 is a partial schematic view of an exemplary cavity cover and upper insulating member shown in accordance with some embodiments of the present description.

As previously described, during crystal production, silicon may move upward from the bottom of growth chamber 110, even evaporating to a gaseous state and continuing to overflow as silicon vapor. The silicon vapor may overflow the chamber cover 130 and adhere to the surface of the upper heat-insulating member 141 in contact with the condensation, thereby affecting the heat-insulating performance. Thus, in some embodiments, as shown in fig. 4, the cavity cover 130 and the upper heat-preserving member 141 may have a gap 131, and carbon powder may be filled in the gap 131 to react the volatilized silicon vapor with the carbon powder, so that the silicon vapor is prevented from overflowing and adhering to the surface of the upper heat-preserving member 141 when meeting condensation, or silicon carbide particles generated by the reaction of the silicon vapor and the growth cavity 110 adhere to the heat-preserving member, thereby affecting the heat-preserving performance thereof.

In some embodiments, as shown in fig. 4, the cavity cover 130 may also include a raised structure 132. Because the temperature near raised structures 132 is lower (below the melt temperature), some of the silicon vapor may condense at raised structures 132 to slow or reduce the overflow of silicon vapor, reducing the level of contamination of upper insulating member 141. After the crystal growth is finished, the raised structures 132 can be cleaned, so that the subsequent use is convenient.

Fig. 5 is a schematic diagram of an exemplary growth chamber according to some embodiments of the present disclosure.

In connection with the foregoing, in the crystal manufacturing process, the raw material is melted into a melt (liquid state) and crystal growth is performed based on the melt, and the growth chamber 110 is required to provide a carbon source required for crystal growth. Therefore, the bottom (or middle lower portion) of the growth chamber 110 is at a higher temperature and consumes more rapidly.

Thus, in some embodiments, the wall thickness of the sidewall of the growth chamber 110 gradually increases along the top-to-bottom direction (as indicated by the arrow in fig. 5) of the growth chamber 110, so that the bottom is prevented from being excessively consumed and thinned, and the number of times of using the growth chamber 110 is further increased.

FIG. 6 is a schematic diagram of an exemplary seed holder and seed crystal according to some embodiments of the present disclosure.

In the process of preparing the crystal, if the seed crystal is too thin, a burn-through phenomenon is easy to occur, the crystal preparation effect is affected, and the seed crystal holder can inevitably contact with the melt due to the fact that the seed crystal is too thin, crystals with different crystal forms and/or crystal directions are generated, and then crystal defects are generated; if the seed crystal with larger thickness is directly used, the cost for preparing the seed crystal is greatly increased.

Thus, in some embodiments, seed 180 may include at least two layers of seed, where the seed for crystal growth (i.e., the lowest layer of seed in direct contact with the melt) may be of higher quality and the other layers of seed may be of relatively lower quality, which may correspondingly reduce cost while increasing the overall thickness of the seed.

In some embodiments, as shown in fig. 6, the at least two layers of seed crystals may include a first seed crystal 181 and a second seed crystal 182, wherein the mass of the first seed crystal 181 may be lower than the mass of the second seed crystal 182.

In some embodiments, the thickness of the first seed crystal 181 may be greater than the thickness of the second seed crystal 182, provided that the second seed crystal 182 meets the crystal growth requirements, to further reduce the cost of the seed crystal 180.

In some embodiments, the bonding means between the seed holder 150 and the first seed crystal 181, the first seed crystal 181 and the second seed crystal 182 may include, but is not limited to, bonding, photoresist, and the like.

Due to the unavoidable presence of voids in the seed holder 150, gas phase material accumulated in the back surface (e.g., the bonding surface of the first seed 181 to the seed holder 150) gap or void region of the seed is caused to escape, resulting in defects (e.g., planar hexagonal void defects) in the final prepared crystal.

Thus, in some embodiments, as shown in FIG. 6, a graphite paper 190 may be filled between the seed holder 150 and the seed 180 (first seed 181). The graphite paper 190 is softer and has higher flatness, which can reduce the porosity of the bonding surface, prevent the back surface of the seed crystal from being heated unevenly, reduce the generation of subsequent defects, and simultaneously improve the bonding strength of the seed crystal holder 150 and the seed crystal 180 (e.g., the first seed crystal 181).

FIG. 7 is a flow chart of an exemplary crystal preparation method according to some embodiments of the present description. In some embodiments, the process 700 may be performed by one or more components in a crystal preparation apparatus (e.g., crystal preparation apparatus 100). In some embodiments, the process 700 may be performed automatically by a control system. For example, the flow 700 may be implemented by control instructions, based on which a control system controls various components to complete various operations of the flow 700. In some embodiments, the process 700 may be performed semi-automatically. For example, one or more operations of flow 700 may be performed manually by an operator. In some embodiments, upon completion of flow 700, one or more additional operations not described above may be added and/or one or more operations discussed herein may be pruned. In addition, the order of the operations shown in fig. 7 is not limiting. As shown in fig. 7, the flow 700 includes the following steps.

At step 710, the feedstock is placed into a growth chamber.

In some embodiments, the feedstock may refer to the feedstock material required to grow the crystal. For example, in growing silicon carbide crystals, the feedstock may include silicon (e.g., silicon powder, silicon wafer, silicon chunk). For another example, in growing silicon carbide crystals, the feedstock may include silicon and carbon (e.g., carbon powder, carbon blocks, carbon particles). In some embodiments, the feedstock includes carbon powder, carbon blocks, or carbon particles, which may increase the number of uses of the growth chamber. In some embodiments, the feedstock may also include a fluxing agent to increase the solubility of carbon in silicon. In some embodiments, the fluxing agent may include, but is not limited to, aluminum, silicon chromium alloys, li-Si alloys, ti-Si alloys, fe-Si alloys, sc-Si alloys, co-Si alloys.

In some embodiments, at least one lamina assembly may be disposed within the growth chamber. For a description of the growth chamber (e.g., growth chamber 110) and at least one plate assembly (e.g., plate assembly 111), reference may be made to other portions of the specification (e.g., fig. 1-5 and descriptions thereof), and no further description is provided herein.

At step 720, the growth chamber is heated by the heating assembly to melt the feedstock into a melt.

For example, when growing silicon carbide crystals, the feedstock melts to form a solution of carbon in silicon as a liquid feedstock for crystal growth.

For a description of a heating assembly (e.g., heating assembly 120), reference may be made to other portions of the specification (e.g., fig. 1 and the description thereof), and no further description is provided herein.

In some embodiments, to increase the utilization of the feedstock, the ratio of melt height to growth cavity height is within a predetermined range. In some embodiments, the height ratio of melt to growth cavity may be in the range of 1:1-1:5. In some embodiments, the height ratio of melt to growth cavity may be in the range of 1:1.5-1:4.5. In some embodiments, the height ratio of melt to growth cavity may be in the range of 1:2-1:4. In some embodiments, the height ratio of melt to growth cavity may be in the range of 1:2.5-1:3.5. In some embodiments, the height ratio of melt to growth cavity may be in the range of 1:2.8-1:3.

In some embodiments, to improve stability of crystal growth, the melt level may be located near the midpoint of the height of the heating assembly (e.g., induction coil). In some embodiments, nearby may refer to within a preset distance. In some embodiments, the predetermined distance may include + -50 cm, + -40 cm, + -30 cm, + -20 cm, + -10 cm, + -8 cm, + -6 cm, + -4 cm, + -2 cm, + -1 cm, and the like. For example, after the raw material is melted into a melt, the melt level may be within + -30 cm of 1/2 of the height of the heating element (e.g., induction coil).

At 730, the seed crystal is bonded to the seed holder.

In some embodiments, the seed crystal may include at least two layers of seed crystal. In some embodiments, the at least two layers of seed crystals may include a first seed crystal and a second seed crystal, the first seed crystal may be bonded to the seed holder, and the second seed crystal may be bonded to the first seed crystal. In some embodiments, the mass of the first seed crystal may be lower than the mass of the second seed crystal.

In some embodiments, the graphite paper may be bonded to the seed holder prior to bonding the seed to the seed holder such that the graphite paper is positioned between the seed holder and the seed. In some embodiments, the seed crystal and/or graphite paper may be concentric with the seed holder.

In some embodiments, the thickness of the graphite paper may be in the range of 0.5mm-1 mm. In some embodiments, the thickness of the graphite paper may be in the range of 0.6mm-0.9 mm. In some embodiments, the thickness of the graphite paper may be in the range of 0.5mm-1 mm. In some embodiments, the thickness of the graphite paper may be in the range of 0.7mm-0.8 mm.

In some embodiments, to ensure bond strength between the graphite paper, the first seed crystal, and the second seed crystal, and to ensure crystal quality. The flatness of the surface of the first seed crystal needs to meet preset conditions. In some embodiments, the flatness of the surface of the first seed crystal adhered to the graphite paper may be less than 0.01mm. In some embodiments, the flatness of the surface of the first seed crystal attached to the second seed crystal may be in the range of 0.005mm-0.008 mm. In some embodiments, the flatness of the surface of the first seed crystal attached to the second seed crystal may be in the range of 0.006mm to 0.007 mm.

For a description of the seed crystal (e.g., seed crystal 180) and the seed holder (e.g., seed holder 150), reference may be made to other portions of this specification (e.g., fig. 6 and the description thereof), and no further description is provided herein.

At 740, the viscosity is reduced to a seed holder with seed crystals attached to bring the seed crystals into contact with the melt.

In some embodiments, the power assembly may be used to drive the connection assembly downward to drive the seed holder downward to bring the seed into contact with the melt.

At step 750, crystals are prepared based on the seed crystal and the melt.

In some embodiments, the power assembly may drive the connecting assembly to rotate and/or move up and down to drive the seed holder to rotate and/or move up and down, and the melt may condense and crystallize at the seed to grow the crystal.

During the crystal growth process, the melt in the growth cavity is convected, the silicon at the lower part moves upwards, part of the silicon can be blocked by the plate component arranged in the growth cavity, and part of the silicon can continue to move upwards through the through holes in the plate component. Since the through holes on adjacent plate members are staggered, a portion of the silicon that continues upward movement is blocked by the plate member above. By repeating the steps, silicon convection to the upper surface of the melt can be obviously reduced, correspondingly, volatilization of the silicon on the upper surface of the melt can be reduced, the pollution degree of the heat insulation component can be further reduced, the heat insulation performance of the heat insulation component is maintained, and normal growth of crystals can be further ensured.

It should be noted that the above description of the process 700 is for purposes of illustration and description only and is not intended to limit the scope of applicability of the application. Various modifications and changes to flow 700 may be made by those skilled in the art in light of the teachings of this application. However, such modifications and variations are still within the scope of the present application.

Possible benefits of embodiments of the present description include, but are not limited to: (1) At least one plate component is arranged in the growth cavity, and the plate component is made of graphite which can be used as a carbon source to provide raw materials required for preparing silicon carbide crystals; (2) The plate assemblies comprise through holes, the through holes on adjacent plate assemblies are mutually staggered, so that the convection of a melt in the growth cavity can be regulated, the rising speed of volatile components (such as silicon) is reduced, the volatilization amount of the volatile components (such as silicon) on the surface of the melt is reduced, the excessive consumption of the volatile components is reduced, silicon carbide particles generated by the reaction of the volatile components (such as silicon vapor) and the growth cavity can be reduced, the pollution degree of the heat preservation assembly can be further reduced, the heat preservation performance of the heat preservation assembly is ensured, and the normal growth of crystals can be further ensured; (3) The upper part of the inner side wall of the growth cavity is coated with a coating or provided with a shielding ring, so that spontaneous nucleation and crystallization growth caused by the reaction of silicon on the surface of a melt and carbon on the side wall of the growth cavity can be avoided; (4) The cavity cover and the upper heat preservation component have gaps, carbon powder is filled in the gaps, and the carbon powder can react with volatilized silicon vapor to prevent the silicon vapor from overflowing to the heat preservation component or silicon carbide particles generated by the reaction of the silicon vapor and the growth cavity from being attached to the heat preservation component to influence the heat preservation performance of the heat preservation component; (5) The cavity cover comprises a protruding structure, so that part of silicon vapor can be condensed at the protruding structure to slow down or reduce the overflow of the silicon vapor, and the pollution degree of the heat preservation component is reduced; (6) The seed crystal comprises at least two layers of seed crystals, so that the thickness of the seed crystals can be increased, the risk of burning through the seed crystals is reduced, and the quality of the prepared crystals can be further ensured; (7) The mass of the first seed crystal bonded to the seed holder may be lower than the mass of the second seed crystal bonded to the first seed crystal to reduce seed crystal costs and further reduce crystal preparation costs. It should be noted that, the advantages that may be generated by different embodiments may be different, and in different embodiments, the advantages that may be generated may be any one or a combination of several of the above, or any other possible advantages that may be obtained.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing detailed disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations to the present disclosure may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this specification, and therefore, such modifications, improvements, and modifications are intended to be included within the spirit and scope of the exemplary embodiments of the present invention.

Meanwhile, the specification uses specific words to describe the embodiments of the specification. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the present description. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present description may be combined as suitable.

Likewise, it should be noted that in order to simplify the presentation disclosed in this specification and thereby aid in understanding one or more inventive embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof. This method of disclosure, however, is not intended to imply that more features than are presented in the claims are required for the present description. Indeed, less than all of the features of a single embodiment disclosed above.

In some embodiments, numbers describing the components, number of attributes are used, it being understood that such numbers being used in the description of embodiments are modified in some examples by the modifier "about," approximately, "or" substantially. Unless otherwise indicated, "about," "approximately," or "substantially" indicate that the number allows for a 20% variation. Accordingly, in some embodiments, numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and employ a method for preserving the general number of digits. Although the numerical ranges and parameters set forth herein are approximations that may be employed in some embodiments to confirm the breadth of the range, in particular embodiments, the setting of such numerical values is as precise as possible.

Each patent, patent application publication, and other material, such as articles, books, specifications, publications, documents, etc., referred to in this specification is incorporated herein by reference in its entirety. Except for application history documents that are inconsistent or conflicting with the content of this specification, documents that are currently or later attached to this specification in which the broadest scope of the claims to this specification is limited are also. It is noted that, if the description, definition, and/or use of a term in an attached material in this specification does not conform to or conflict with what is described in this specification, the description, definition, and/or use of the term in this specification controls.

Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments of this specification. Other variations are possible within the scope of this description. Thus, by way of example, and not limitation, alternative configurations of embodiments of the present specification may be considered as consistent with the teachings of the present specification. Accordingly, the embodiments of the present specification are not limited to only the embodiments explicitly described and depicted in the present specification.

Claims (10)

1. A crystal preparation apparatus for preparing crystals by a liquid phase method, the apparatus comprising:

a growth cavity, at least one layer of plate component is arranged in the growth cavity, wherein,

the at least one layer of plate assembly comprises a through hole;

for at least one of the at least one plate assembly, the ratio of the sum of the opening areas of the through holes to the upper surface area of the plate assembly is in the range of 30% -80%;

a heating assembly for heating the growth chamber;

the connecting assembly is used for connecting the seed crystal support to support the seed crystal; and

and the power assembly is used for driving the connecting assembly to rotate and/or move up and down so as to drive the seed crystal holder to rotate and/or move up and down.

2. The crystal production apparatus of claim 1 wherein the plate assembly is located within a melt within the growth chamber and a predetermined distance below the melt level.

3. The crystal production apparatus of claim 1 wherein the spacing between adjacent plate assemblies is in the range of 10mm to 60 mm.

4. The crystal production apparatus of claim 1 wherein the density of the through holes decreases gradually from the center to the edge of the plate assembly.

5. The crystal production apparatus of claim 1 wherein a ratio of a density of through holes near a center of the plate assembly to a density of through holes near an edge of the plate assembly is in a range of 1:1-20:1.

6. The crystal production apparatus of claim 1, wherein the diameter of the through hole is in the range of 0.1mm to 10 mm.

7. The crystal production apparatus of claim 1 wherein an upper predetermined area of the growth chamber side wall is coated or provided with a shield ring.

8. The crystal production apparatus of claim 1 further comprising a chamber cover and an upper heat retaining member, wherein a gap between the chamber cover and the upper heat retaining member is filled with carbon powder.

9. The crystal production apparatus of claim 8 wherein the cavity cover comprises a raised structure.

10. The crystal production apparatus of claim 1 wherein the wall thickness of the growth chamber side wall increases gradually in a top-to-bottom direction of the growth chamber.

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