CN218711041U - Growth device for preparing silicon carbide crystals - Google Patents

Abstract

The utility model discloses a growth device of preparation carborundum crystal, the device includes: a first crucible defining a reaction chamber; the seed crystal is arranged in the reaction cavity and defines a growth cavity extending in the vertical direction; the second crucible, the second crucible sets up in the reaction chamber, places the carborundum powder in the second crucible, and the growth cavity of seed crystal is opened towards carborundum powder one side, and the second crucible extends to in the growth cavity, and the part that extends to the growth cavity is equipped with the water conservancy diversion hole that communicates the growth cavity, and the carborundum steam of carborundum powder sublimation enters into the growth cavity through the water conservancy diversion hole in, grows out carborundum crystal at the internal surface undergauge of seed crystal. The utility model discloses an adopt cyclic annular seed crystal and the mode that the undergauge grows, thereby multiple defect in the seed crystal is because the difference of growth mode can't be inherited to reduce crystal defect, sublimed gas is used for growing by the seed crystal parcel, reduces the loss.

Description

Growth device for preparing silicon carbide crystals

Technical Field

The utility model belongs to the technical field of the carborundum and specifically relates to a growth device for preparing carborundum crystal is related to.

Background

Semiconductor silicon carbide single crystal materials have evolved through the last 30 years since their commercialization in the 90 s of the last century as the preferred substrate material for power electronics and microwave radio frequency devices. The most mature technology for preparing silicon carbide single crystal at present is physical vapor transport method (PVT method for short), the basic principle is that a graphite crucible placed in the center of a coil is heated by medium-frequency induction, the wall of the graphite crucible generates heat by induction and then transmits the heat to silicon carbide powder inside the graphite crucible to cause the silicon carbide powder to sublime, and meanwhile, a seed crystal is arranged at the top of the crucible to serve as a crystal growth base point. Conventional designs have a degree of radial temperature gradient that can lead to thermal stresses within the crystal, which in turn can lead to crystal breakage.

The conventional PVT method uses a sheet-shaped seed crystal for crystal growth, and the height of the crystal is between 15 and 25mm during the growth process. The existing crystal growth methods mainly comprise equal-diameter growth and expanding growth, and have the following advantages and disadvantages:

(1) Defects such as micropipes and TSDs are inherited, and if they are present in a conventional seed crystal during growth, they may extend through the entire ingot during growth, and the wafers cut therefrom may also be present.

(2) In the traditional seed crystal growth process, heat is conducted to the inside from the side wall of the crucible, so that a certain radial temperature gradient exists, and the radial temperature gradient easily causes stress generation, thereby generating defects such as phase change, cracks and the like.

(3) In the traditional crucible design, the temperature at the bottom of the crucible is higher in the growth process, and the silicon carbide powder near the bottom of the crucible reacts firstly. The silicon carbide powder is subjected to physical and chemical changes and is firstly decomposed to generate Si and SiC ₂ ，Si ₂ C gas, after which the gas rises. The residual carbon powder is retained in the crucible and occupies the space at the bottom of the crucible, so that the upper silicon carbide powder cannot fall to the bottom of the crucible to be heated and then volatilize. Thereby making the raw material insufficiently used and being not beneficial to the growth of crystals with larger height. Meanwhile, the temperature of the central area (i.e., area a in fig. 14) of the middle upper portion of the silicon carbide powder is low, and the sublimation temperature is not reached, which causes waste of raw materials.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides a growth device for preparing silicon carbide crystals.

In order to achieve the above object, the present invention provides the following technical embodiments:

according to a first aspect of the present invention, a growing apparatus for producing silicon carbide crystals is provided.

The growth device for preparing the silicon carbide crystal comprises:

a first crucible defining a reaction chamber;

the seed crystal is arranged in the reaction cavity and defines a growth cavity extending in the vertical direction;

the second crucible is arranged in the reaction cavity, silicon carbide powder is placed in the second crucible, the growth cavity of the seed crystal is opened towards one side of the silicon carbide powder, the second crucible extends into the growth cavity, the part extending to the growth cavity is provided with a flow guide hole communicated with the growth cavity, and silicon carbide vapor sublimed by the silicon carbide powder enters the growth cavity through the flow guide hole, so that silicon carbide crystal grows on the inner surface of the seed crystal in a diameter reduction manner.

In some embodiments of the present invention, the seed crystal includes a first seed crystal portion, the first seed crystal portion has an annular tubular structure, and the growth cavity penetrates the first seed crystal portion in the up-down direction.

In some embodiments of the present invention, the seed crystal further comprises a second seed crystal portion, the second seed crystal portion being sealingly disposed at an upper end of the first seed crystal portion, the first seed crystal portion and the second seed crystal portion defining the growth cavity together.

In some embodiments of the present invention, the second crucible includes a crucible main body and a dome, the upper end of the crucible main body is detachably connected to the dome, the crucible main body is used for holding the silicon carbide powder, and the dome forms an air flow channel and extends into the growth cavity.

In some embodiments of the present invention, the guiding cover comprises a guiding tube and a guiding tube, the guiding tube is detachably connected to the crucible main body, the radial sectional area of the guiding tube is smaller than the radial sectional area of the crucible main body, the guiding tube extends into the growth cavity of the seed crystal, and the guiding hole is disposed on the guiding tube.

In some embodiments of the present invention, a gas flow control member is disposed in the second crucible, the gas flow control member being rotatably disposed in the gas flow passage for controlling the flow of the silicon carbide gas from the second crucible into the growth cavity.

In some embodiments of the present invention, the airflow control member includes a baffle plate assembly and an inner rotary shaft, the inner rotary shaft penetrates through the crucible main body and extends into the upper portion of the dome, the top fixed connection of the inner rotary shaft is the baffle plate assembly, the baffle plate assembly corresponds to the diversion hole, and the inner rotary shaft is rotatable, so that the baffle plate assembly blocks or opens the diversion hole.

In some embodiments of the present invention, the guide tube is in an inverted conical shape, and the guide tube is located at the center of the upper end of the guide tube.

The utility model discloses an in some embodiments, the even spaced apart multiseriate that is equipped with of circumference on the lateral wall of kuppe water conservancy diversion hole, the separation blade subassembly includes a plurality of separation blades that the up end center of interior rotation axis set up as centre of a circle, circumference interval, the separation blade subassembly forms the lateral wall separation blade at the perpendicular downwardly extending in the border of every separation blade, the lateral wall separation blade is used for right water conservancy diversion hole on the lateral wall of honeycomb duct shelters from, the lateral wall separation blade extends to at least and is located honeycomb duct lateral wall bottommost the lower border in water conservancy diversion hole, the separation blade with water conservancy diversion hole one-to-one sets up.

In some embodiments of the utility model, the guiding tube with the relative part of seed crystal is protruding upwards and is formed the side portion of giving vent to anger, the side portion of giving vent to anger is the ring form, the gas outlet has evenly been seted up to the up end of the side portion of giving vent to anger, the inside wall of the side portion of giving vent to anger extends upwards and forms annular side shield, the external diameter of side shield equals the internal diameter of seed crystal.

In some embodiments of the utility model, the concatenation seed crystal is connected to the one end of seed crystal that is close to the carborundum powder, the concatenation seed crystal is at least one, the concatenation seed crystal is annular tubular structure, the internal diameter of concatenation seed crystal with the internal diameter of seed crystal is the same, the external diameter of concatenation seed crystal with the external diameter of seed crystal is the same.

Compared with the prior art, the utility model discloses following beneficial effect has:

(1) The utility model discloses an adopt the mode that cyclic annular seed crystal and undergauge were grown, thereby defects such as micropipe and dislocation in the seed crystal can't be inherited owing to the difference of growth mode to reduce crystal defect.

(2) The kuppe adopts the graphite material, consequently has certain effect of generating heat, and the honeycomb duct of kuppe stretches into to the growth cavity of seed crystal, and the honeycomb duct is by the central axis of seed crystal to giving off the heat all around, and the heat that the honeycomb duct gived off can provide certain heat to seed crystal central direction to reduce radial temperature gradient, reduce the production of seed crystal growth in-process stress, thereby reduce defects such as phase transition, improve crystal quality.

(3) The air guide sleeve is made of graphite, so that a certain heating effect is achieved, the condition that the central region of the middle upper portion of the second crucible is insufficient in heating amount can be made up through the design of the air guide sleeve, powder of the middle upper layer can be fully utilized under the heat supplement of the air guide sleeve, and the defect that silicon carbide powder cannot be fully utilized in the traditional crucible is overcome.

(4) The utility model discloses the growth method of silicon carbide crystal utilizes the gaseous sublimation rate of different atmospheric pressure value stage control to control crystal growth rate. The movement of the stage at different stages is adapted to the same air pressure value of the crystal at different growth stages. Because of the particularity of the seed crystal, the traditional isobaric growth process is not applicable any more, and the process can better start crystal growth in the first stage, accelerate the crystal growth in the second stage and carry out final growth in the third stage. The diameter-reducing growth process of the annular seed crystal adopted by the process can avoid the extension characteristic of inevitable partial defects of the traditional seed crystal growth method, greatly reduce the dislocation of the crystal ingot and improve the crystal quality. Meanwhile, the silicon carbide powder can be fully utilized due to the coating property of the annular seed crystal, and cost saving is facilitated.

Drawings

FIG. 1 is a schematic view of a growing apparatus for producing silicon carbide crystals according to example 1 of the present invention;

FIG. 2 is a schematic view of the second crucible shown in FIG. 1;

FIG. 3 is a perspective view of the seed crystal shown in FIG. 1;

FIG. 4 is a schematic view of a growing apparatus for producing silicon carbide crystals according to example 2 of the present invention;

FIG. 5 is a perspective view of the upper portion of the airflow control member of FIG. 4;

FIG. 6 is an enlarged view of the airflow control member of FIG. 4;

FIG. 7 is a schematic view showing the baffle assembly partially shielding the guide cylinder on the guide pipe in embodiment 2;

FIG. 8 is a schematic view of a growing apparatus for producing silicon carbide crystals according to example 3 of the present invention;

FIG. 9 is a schematic view of a growing apparatus for producing silicon carbide crystals according to embodiment 4 of the present invention;

FIG. 10 is a schematic view of a growing apparatus for producing silicon carbide crystals according to example 5 of the present invention;

FIG. 11 is a schematic view of a growing apparatus for producing silicon carbide crystals according to example 6 of the present invention;

fig. 12 is a schematic view of an airflow control part according to embodiment 6 of the present invention at different time periods, where a is a view showing that the airflow control part completely blocks the diversion hole at the top of the diversion pipe, B is a view showing that the airflow control part partially blocks the diversion hole at the top of the diversion pipe, and C is a view showing that the airflow control part completely opens the diversion hole at the top of the diversion pipe;

FIG. 13 is a schematic view of the upper portion of the draft tube of FIG. 11;

FIG. 14 is a schematic view of a prior art growing apparatus for producing a silicon carbide crystal.

Reference numerals:

the growing device 100 for preparing the silicon carbide crystal, the heat insulation layer 200, the quartz tube 300, the induction coil 400:

a first crucible 10, a second crucible 20 and a seed crystal 30.

A reaction chamber 11;

the crucible comprises a crucible body 21, a flow guide cover 22, a flow guide pipe 221, a guide pipe 222, an airflow channel 223, a side gas outlet part 224, a side baffle 225, a flow guide hole 2211 and a gas outlet 2241;

a growth cavity 31, a first seed crystal portion 32, a second seed crystal portion 33,

a bearing platform 40, a bearing platform rotating lifting shaft 41, a bottom heat-insulating layer 42 and a through hole 43;

the airflow control member 50, the flap assembly 51, the inner rotating shaft 52, the flaps 511, the sidewall flaps 512;

splicing the seed crystals 60;

silicon carbide powder 70.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below by referring to the drawings are exemplary intended for explaining the present invention, and should not be construed as limiting the present invention.

The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. In order to simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present disclosure provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize the applicability of other processes and/or the use of other materials.

A growing apparatus 100 for producing a silicon carbide crystal according to an embodiment of the present invention is described below with reference to fig. 1-12 for producing a silicon carbide crystal.

Referring to fig. 1, growth device 100 for preparing silicon carbide crystal is disposed in a vacuum furnace (not shown in the figure), the outside of growth device 100 for preparing silicon carbide crystal is provided with a heat preservation layer 200, wherein the outer diameter of the part of heat preservation layer 200 located outside seed crystal 30 is gradually reduced from bottom to top, growth device 100 for preparing silicon carbide crystal is disposed in quartz tube 300, induction coil 400 is surrounded outside quartz tube 300, growth device 100 for preparing silicon carbide crystal is heated by induction coil 400, because the outer diameter of the part of heat preservation layer 200 located outside seed crystal 30 is gradually reduced from bottom to top, the temperature gradient of the seed crystal region can be established in the axial direction, namely, the temperature of seed crystal 30 is gradually reduced from bottom to top, the thicker position temperature of 200 is higher, growth can be smoothly carried out on the growth surface when silicon carbide gas enters the seed crystal region, heat preservation layer 200 in the vacuum furnace, quartz tube 300 and induction coil 400 are well known by those skilled in the art, which does not belong to the improvement point of the present invention, so a detailed description is different.

Referring to fig. 1 and 2, a growing apparatus 100 for preparing silicon carbide crystals according to an embodiment of the present invention includes: a first crucible 10, a second crucible 20 and a seed crystal 30;

the first crucible 10 defines a reaction chamber 11; the second crucible 20 and the seed crystal 30 are arranged in the reaction cavity 11, the seed crystal 30 is fixed at the top of the reaction cavity 11, the seed crystal 30 defines a growth cavity 31 extending in the up-down direction, one side of the growth cavity 31 of the seed crystal 30 facing the silicon carbide powder 70 is open, the second crucible 20 is arranged at the lower part of the reaction cavity 11, the silicon carbide powder 70 is placed in the second crucible 20, the second crucible 20 extends into the growth cavity 31, and the part extending to the growth cavity 31 is provided with a flow guide hole 2211 communicated with the growth cavity 31, during the growth process, the induction coil 400 carries out induction heating on the quartz tube 300 and the first crucible 10 and the second crucible 20 inside, the silicon carbide powder 70 is heated and sublimated into silicon carbide vapor which enters the growth cavity 31 through the flow guide hole 2211, and silicon carbide crystals grow on the inner surface of the seed crystal 30 in a diameter reduction mode.

The second crucible 20 is fixed on the bearing platform 40, the bearing platform rotating and lifting shaft 41 is connected to the center of the lower surface of the bearing platform 40, and the bearing platform rotating and lifting shaft 41 is used for driving the bearing platform 40 and the second crucible 20 to rotate and lift. The below fixed connection bottom heat preservation 42 of cushion cap 40, bottom heat preservation 42 center is connected with cushion cap rotatory lift shaft 41, so, when cushion cap rotatory lift shaft 41 drove cushion cap 40 and the rotatory elevating movement of second crucible 20, bottom heat preservation 42 also follows elevating movement simultaneously, bottom heat preservation 42 follows the bottom movement of second crucible 20, can guarantee the stability of relative position between second crucible 20 bottom and the bottom heat preservation 42, promote the heat preservation effect, ensure the normal sublimation of carborundum powder 70.

In some embodiments of the present invention, referring to fig. 1 and 3, the seed crystal 30 includes a first seed crystal portion 32, the first seed crystal portion 32 is a ring-shaped cylindrical structure, and the growth cavity 31 penetrates the first seed crystal portion 32 in the up-down direction. In other words, the seed crystal 30 has a ring-shaped structure, so that during crystal growth, the silicon carbide gas shrinks and grows a silicon carbide crystal on the inner side wall surface of the seed crystal 30, and the height of the grown silicon carbide crystal is the same as that of the first seed crystal part 32.

In another embodiment of the present invention, referring to fig. 10 and 11, the seed crystal 30 includes a first seed crystal portion 32 and a second seed crystal portion 33, the second seed crystal portion 33 is sealed at one end of the first seed crystal portion 32, the first seed crystal portion 32 and the second seed crystal portion 33 define a growth cavity 31 together, in other words, the whole seed crystal 30 is top-sealed, the bottom end is open cylindrical, in other words, the seed crystal 30 is an annular structure with a cover at the upper end, so, when growing, the silicon carbide gas grows a silicon carbide crystal in the inner side wall and the inner top wall of the seed crystal 30 by reducing the diameter, and the height of the grown silicon carbide crystal is the same as the sum of the heights of the first seed crystal portion 32 and the second seed crystal portion 33.

Wherein, the first crucible 10 and the second crucible 20 are made of graphite.

Referring to fig. 1, 2, 4 and 8, the second crucible 20 comprises a crucible main body 21 and a guide hood 22, wherein the upper end of the crucible main body 21 is detachably connected with the guide hood 22, the crucible main body 21 is used for containing silicon carbide powder 70, the mass of the silicon carbide powder 70 can be 4kg-5kg, and the guide hood 22 defines a gas flow passage 223 and extends into the growth cavity 31. The upper end of crucible main part 21 can be dismantled with kuppe 22 and be connected, makes things convenient for placing of carborundum powder 70 in earlier stage, also makes things convenient for later stage clearance and maintenance. The specific connection mode can adopt common modes such as threaded connection, buckle connection and the like.

Referring to fig. 1 and 2, the guide housing 22 includes a guide pipe 221 and a guide pipe 222 integrally connected from top to bottom, the guide pipe 222 is detachably connected to the crucible main body 21, and the guide pipe 221 is located at the center of the upper end of the guide pipe 222. The radial sectional area of the guiding tube 222 is gradually reduced, the radial sectional area of the guiding tube 221 is smaller than that of the crucible main body 21, in other words, the guiding tube 222 is in an inverted cone shape, the guiding tube 221 is in a round tube shape with a sealed top and an open bottom, the aperture of the guiding tube 221 is smaller than that of the top end of the guiding tube 222, the guiding tube 221 extends into the growth cavity 31 of the seed crystal 30, and the guiding hole 2211 is arranged on the guiding tube 221. Specifically, when the seed crystal 30 only comprises the first seed crystal part 32, referring to fig. 1 and 2, the side wall of the draft tube 221 in the growth cavity 31 is uniformly provided with the flow guide holes 2211 along the circumferential direction, the silicon carbide gas is ejected from the flow guide holes 2211 circumferentially arranged on the side wall of the draft tube 221, the gas is uniformly distributed on the inner side wall of the seed crystal 30, and the crystal can achieve the purpose of uniform growth; when the seed crystal 30 includes the first seed crystal portion 32 and the second seed crystal portion 33, referring to fig. 10, fig. 12 and fig. 13, that is, the whole seed crystal 30 is cylindrical with a top end sealed and a bottom end open, the upper end surface of the draft tube 221 is uniformly provided with the draft holes 2211, the side wall of the draft tube 221 in the growth cavity 31 is also uniformly provided with the draft holes 2211 along the circumferential direction, the upper end surface of the draft tube 221 and the draft holes on the side wall are correspondingly arranged, the height L2 of the area formed by the draft holes 2211 at the uppermost end of the side wall of the draft tube 221 and the draft holes 2211 at the bottom end is higher than the height L1 of the seed crystal 30, the silicon carbide gas is ejected from the draft holes 2211 at the top of the draft tube 221 and the draft holes 2211 circumferentially arranged on the side wall, the gas is uniformly distributed on the inner top wall and the inner side wall of the seed crystal 30, so that the crystal grows on the inner top wall and the inner side wall of the seed crystal 30 at the same time.

Referring to fig. 14, in the conventional silicon carbide crystal growth process, the temperature at the bottom of the second crucible 20 is the highest, and the temperature at the side wall of the second crucible 20 is lower than the bottom temperature, so the silicon carbide powder 70 at the bottom of the second crucible 20 is sublimated first, and the temperature at the central area (i.e., area a) at the middle upper part is the lowest, the heat of the silicon carbide powder 70 at the area a needs to be conducted from the silicon carbide powder 70 at the area B, in order to make the temperature at the area a reach the sublimation temperature, the conducted heat needs to be increased, at this time, the temperature at the area B needs to be further increased, and the increase of the temperature of the silicon carbide powder 70 at the area B over the carbonization temperature can cause the increase of the carbon coating content, and the crystal quality is affected. If the carbon coating in the B region is reduced, the temperature in the B region cannot be increased further, but the silicon carbide powder 70 in the A region cannot be sublimated due to insufficient temperature, resulting in waste of raw materials. The utility model discloses a set up kuppe 22 in the upper end of second crucible 20, kuppe 22 and second crucible 20 form the environment sealed relatively, can reduce the heat on carborundum powder 70 upper portion and scatter and disappear, play heat retaining effect, simultaneously because kuppe 22's guiding tube 222 is coniform, heat supply is carried out to the A region to the heat radiation of guiding tube 222 through kuppe 22, make the regional carborundum granule 70 of A when reaching the required temperature of sublimation, no longer rely on the heat-conduction of the regional carborundum granule 70 of B completely. The temperature increase in zone B is reduced, thereby reducing carbon pack caused by the temperature increase in zone B silicon carbide powder 70 while utilizing zone a silicon carbide powder 70.

In some embodiments of the present invention, referring to fig. 4-9 and 11-12, a gas flow control member 50 is disposed in the second crucible 20, the gas flow control member 50 being rotatably disposed in the gas flow passage 223 for controlling the flow of the silicon carbide gas from the second crucible 20 into the growth cavity 31. The gas flow control member 50 comprises a baffle assembly 51 and an inner rotating shaft 52, the inner rotating shaft 52 penetrates through the crucible body 21 and extends into the upper part of the flow guide cover 22, the top of the inner rotating shaft 52 is fixedly connected with the baffle assembly 51, and the baffle assembly 51 is arranged corresponding to the flow guide hole 2211 and used for shielding the flow guide hole 2211. Referring to fig. 7, 12 and 13, when the inner rotating shaft 52 rotates a certain angle, the baffle plate assembly 51 can completely block, partially block and completely open the flow guide hole 2211, so as to control the gas flow output and further control the crystal growth speed. A through hole 43 is opened at the center of the bearing platform rotating and lifting shaft 41, an inner rotating shaft 52 is arranged in the through hole 43 of the bearing platform rotating and lifting shaft 41, and the upper end of the inner rotating shaft 52 extends out of the through hole 43 of the bearing platform rotating and lifting shaft 41 to the upper part of the guide pipe 221.

In some embodiments of the present invention, referring to fig. 4-6 and 12, the inner rotating shaft 52 is rod-shaped, the baffle plate assembly 51 is vertically fixed on the top of the inner rotating shaft 52, the baffle plate assembly 51 includes a plurality of baffle plates 511 disposed at intervals circumferentially with the center of the upper end surface of the inner rotating shaft 52 as a circle center, the number of the baffle plates 511 is equal to the number of the rows of the flow guiding holes 2211 on the sidewall of the flow guiding pipe 221, the baffle plates 511 are used for shielding the flow guiding holes 2211 on the upper end surface of the airflow channel 223, the edge of the baffle plates 511 is arc-shaped corresponding to the inner sidewall of the flow guiding pipe 221, and a gap is left between the edge of the baffle plates 511 and the sidewall of the flow guiding pipe 221;

the baffle assembly 51 extends vertically downward at the edge of each baffle 511 to form a sidewall baffle 512, the sidewall baffle 512 is used for shielding the diversion holes 2211 on the sidewall of the diversion cover 22, and the sidewall baffle 512 extends at least to the lower edge of the diversion hole 2211 at the bottommost portion of the sidewall of the diversion cover 22.

In some embodiments of the present invention, referring to fig. 8, the one end of the seed crystal 30 close to the silicon carbide powder 70 is connected to the splicing seed crystal 60, the splicing seed crystal 60 is at least one, the splicing seed crystal 60 is an annular tube-shaped structure, the center of the splicing seed crystal 60 is through from top to bottom, the inner diameter of the splicing seed crystal 60 is the same as the inner diameter of the seed crystal 30, and the outer diameter of the splicing seed crystal 60 is the same as the outer diameter of the seed crystal 30. Thus, the height of the grown silicon carbide crystal is the sum of the heights of the seed crystal 30 and the splicing seed crystal 60, and thus, the growth of the high-height silicon carbide crystal can be realized through the arrangement of the splicing seed crystal 60.

In some embodiments of the utility model, refer to fig. 9 and show, guide tube 222 is that the bottom is uncovered, the top is sealed cylindricly, the hole that communicates with honeycomb duct 221 is seted up at the up end center of guide tube 222, guide tube 222 and the relative part of seed crystal 30 upwards protruding formation side gas outlet portion 224, side gas outlet portion 224 is the ring form, gas outlet 2241 has evenly been seted up to the up end of side gas outlet portion 224, side gas outlet portion 224 just sets up to the lower terminal surface of seed crystal 30, the inside wall of side gas outlet portion 224 upwards extends and forms annular side shield 225, the external diameter of side shield 225 equals the internal diameter of seed crystal 30. So, the in-process of growing the brilliant, inside some carborundum gas entered into the seed crystal 30 through guide tube 222, honeycomb duct 221, carry out the undergauge growth at seed crystal 30 internal surface, another part carborundum gas grows at the lower terminal surface of seed crystal 30 for the height of seed crystal 30 increases, moves down through second crucible 20, can carry out the undergauge crystal growth to the seed crystal 30 inner wall of newly growing out, so, can realize the growth of high-height carborundum crystal.

Examples

The growing apparatus 100 for preparing silicon carbide crystals according to the present invention will be further described with reference to the following embodiments. It will be understood by those skilled in the art that the following examples are illustrative of the present invention only and should not be taken as limiting the scope of the invention.

Example 1

As shown in fig. 1 to 3, a silicon carbide crystal growth apparatus 100 of the present embodiment includes: a first crucible 10, a second crucible 20 and a seed crystal 30.

The first crucible 10 defines a reaction chamber 11; the second crucible 20 and the seed crystal 30 are arranged in the reaction cavity 11, the seed crystal 30 is fixed at the top of the reaction cavity 11, the seed crystal 30 is in an annular tubular structure (hereinafter referred to as annular seed crystal), the second crucible 20 is arranged at the lower part of the reaction cavity 11, the second crucible 20 comprises a crucible main body 21 and a flow guide cover 22, the upper end of the crucible main body 21 is connected with the flow guide cover 22 in a buckling mode, the crucible main body 21 is used for containing silicon carbide powder 70, and the flow guide cover 22 forms an air flow channel 223 and extends into the growth cavity 31.

The guide cover 22 comprises a guide pipe 221 and a guide pipe 222 which are integrally connected from top to bottom, the guide pipe 222 is in snap-fit connection with the crucible body 21, and the guide pipe 221 is positioned at the center of the upper end of the guide pipe 222. The guiding tube 222 is conical, the guiding tube 221 is in the shape of a circular tube with a sealed top and an open bottom, the guiding tube 221 extends into the growth cavity 31 of the seed crystal 30, the top end of the guiding tube 221 is flush with the top end of the seed crystal 30, and the height L2 of an area formed by the guiding hole 2211 at the uppermost end of the side wall of the guiding tube 221 and the guiding hole 2211 at the bottom end is 10mm higher than the height L1 of the seed crystal 30 (refer to fig. 1). The side wall of the draft tube 221 in the growth cavity 31 is uniformly provided with the flow guide holes 2211 along the circumferential direction, the silicon carbide gas is sprayed out from the flow guide holes 2211 circumferentially arranged on the side wall, and the gas is uniformly distributed on the inner side wall of the seed crystal 30, so that the crystal grows on the inner side wall of the seed crystal 30 in a diameter reduction manner.

The second crucible 20 is fixed on the bearing platform 40, the bearing platform rotating and lifting shaft 41 is connected to the center of the lower surface of the bearing platform 40, and the bearing platform rotating and lifting shaft 41 is used for driving the bearing platform 40 and the second crucible 20 to rotate and lift. The bottom heat-insulating layer 42 is fixedly connected below the bearing platform 40, the center of the bottom heat-insulating layer 42 is connected with the bearing platform rotating lifting shaft 41, and thus, when the bearing platform 40 and the second crucible 20 are driven by the bearing platform rotating lifting shaft 41 to rotate and lift, the bottom heat-insulating layer 42 also moves along with the lifting movement.

In this embodiment, the seed crystal 30 is an annular seed crystal and has no top cap. The inner diameter of the seed crystal 30 is 152mm, and the outer diameter of the seed crystal 30 is 153mm. The seed crystal 30 has a thickness of 500 μm (i.e., the difference between the radius of the outer circle and the radius of the inner circle of the seed crystal 30 is 500 μm) and a height of 25mm. The seed crystal 30 is fixed to the inner wall of the first crucible 10 by means of bonding.

The process flow comprises the following steps:

the silicon carbide powder 70 is heated and sublimated, and the sublimation gas rises. The sublimation gas inside the crucible main body 21 is transported toward the seed crystal 30 through the guide hood 22. The gas enters the growth cavity of the seed crystal 30 through the diversion holes 2211 formed on the side wall of the diversion pipe 221 to start growing.

The growth is divided into three stages, namely a first stage of 10 hours, the air pressure of the first stage is controlled to be 7mbar, the temperature of the silicon carbide powder 70 is controlled to be 2300-2350 ℃, and the sublimation rate is controlled to be 8-10 g/h.

In the second stage 120h, after the first stage 10h, the crucible body 21 drives the draft tube 221 to rotate at a rotation speed of 1r/min. While rotating, the platform 40 is gradually lowered, and the lowering rate is kept at 0.3mm/h. When the second stage is finished, the second crucible 20 descends by 36mm, the top of the draft tube 221 is 11mm lower than the bottom of the seed crystal 30, and the growth pressure is controlled to be 2-4 mbar. And when the preset descending height is reached, stopping descending, keeping rotating, and finishing the second stage.

And in the third stage 10h, the rotating speed is uniformly reduced, and the air pressure is controlled at 7mbar until the crystal growth is finished.

The main purpose of the first stage is to initiate growth, and the slower growth rate ensures a stable alignment of the initial atoms. And waiting until the atomic arrangement is completed. And (3) carrying out second-stage growth after a period of time, reducing the pressure intensity in the stage, and improving the sublimation rate of the powder so as to improve the growth rate. When the growth enters the ending stage, namely the third stage, the growth speed is reduced again, the pressure is increased, atoms can fill the final growth gap, and meanwhile, the stability of the final arrangement can be ensured.

Example 2

This embodiment differs from embodiment 1 only in that,

referring to fig. 4-7, an air flow control member 50 is disposed in the second crucible 20, the air flow control member 50 includes a baffle plate assembly 51 and an inner rotating shaft 52, the inner rotating shaft 52 penetrates through the crucible body 21 and extends into the upper portion of the guiding cover 22, the inner rotating shaft 52 is rod-shaped, the baffle plate assembly 51 is vertically fixed on the top of the inner rotating shaft 52, the baffle plate assembly 51 is fixedly connected to the top of the inner rotating shaft 52, the baffle plate assembly 51 includes a baffle plate 511 disposed corresponding to the guiding hole 2211 on the sidewall of the guiding pipe 221, the edge of the baffle plate 511 is arc-shaped and is adapted to the inner sidewall of the guiding pipe 221, and a gap is left between the edge of the baffle plate 511 and the sidewall of the guiding pipe 221.

The baffle assembly 51 extends vertically downward at the edge of each baffle 511 to form a sidewall baffle 512, the sidewall baffle 512 is used for shielding the flow guide holes 2211 on the sidewall of the flow guide cover 22, and the sidewall baffle 512 extends at least to the lower edge of the flow guide hole 2211 at the bottommost of the sidewall of the flow guide pipe 221. The inner rotating shaft 52 rotates a certain angle, so that the diversion hole 2211 can be completely shielded, partially shielded and completely opened. A through hole 43 is opened at the center of the bearing platform rotating and lifting shaft 41, an inner rotating shaft 52 is arranged in the through hole 43 of the bearing platform rotating and lifting shaft 41, and the upper end of the inner rotating shaft 52 extends out of the through hole 43 of the bearing platform rotating and lifting shaft 41 to the upper part of the guide pipe 221.

The inner rotating shaft 52 is provided inside the draft tube 221 to control the gas flow rate. The growth temperature is not changed, and the opening degree of the flow guide hole 2211 can be controlled by adjusting the angle of the inner rotating shaft 52. In the first stage of growth, the inner rotating shaft 52 is controlled to open all the flow guide holes 2211 on the side wall, so that sufficient gas is provided in the early stage to promote growth. And closing the top air hole after the first stage is finished, slowing down the upper air flow, and maintaining the growth in a stable state until the growth is finished. The gas pressure and the growth phase were the same as in example 1.

Example 3

This embodiment is different from embodiment 2 only in that, as shown with reference to fig. 8,

one end of the seed crystal 30 close to the silicon carbide powder 70 is connected with a splicing seed crystal 60, the splicing seed crystal 60 is in an annular cylindrical structure, the inner diameter of the splicing seed crystal 60 is the same as that of the seed crystal 30, and the outer diameter of the splicing seed crystal 60 is the same as that of the seed crystal 30.

Thus, the height of the grown silicon carbide crystal is the sum of the heights of the seed crystal 30 and the splicing seed crystal 60, and thus, the growth of the high-height silicon carbide crystal can be realized through the arrangement of the splicing seed crystal 60.

In the embodiment, the seed crystal 30 and the splicing seed crystal 60 are spliced, and the height of the seed crystal 30 is increased after splicing. The temperature is controlled between 2325 and 2370 ℃, and in order to improve the sublimation rate, the air pressure in the second stage is reduced to 1 to 3mbar. The growth of this example is divided into three stages, the first stage and the third stage are the same as the previous examples, but the gas pressure is changed, the first stage is 4-6 mbar, and the third stage is 4-6 mbar. In the second stage, the crystal growth time is prolonged to 150 hours, and the descending rate of the bearing platform 40 is controlled to be 0.4mm/h.

Example 4

This embodiment is different from embodiment 2 only in that, as shown with reference to fig. 9,

the guide tube 222 is in a cylindrical shape with an open bottom and a sealed top, the part, opposite to the seed crystal 30, of the upper end surface of the guide tube 222 protrudes upwards to form a side gas outlet part 224, the side gas outlet part 224 is in a circular ring shape, the upper end surface of the side gas outlet part 224 is provided with gas outlets 2241 uniformly, the side gas outlet part 224 is arranged right opposite to the lower end surface of the seed crystal 30, the inner side wall of the side gas outlet part 224 extends upwards to form an annular side baffle 225, and the outer diameter of the side baffle 225 is equal to the inner diameter of the seed crystal 30.

So, the in-process of growing the brilliant, inside some carborundum gas entered into the seed crystal 30 through guide tube 222, honeycomb duct 221, carry out the undergauge growth at seed crystal 30 internal surface, another part carborundum gas grows at the lower terminal surface of seed crystal 30 for the height of seed crystal 30 increases, moves down through second crucible 20, can carry out the undergauge crystal growth to the seed crystal 30 inner wall of newly growing out, so, can realize the growth of high-height carborundum crystal.

In this embodiment, the structure of the pod 22 is changed, and the side air outlet portion 224 is newly added.

The process flow comprises the following steps:

the temperature of the silicon carbide powder 70 is controlled to be 2325-2370 ℃, the pressure in the first stage is controlled to be 5-7mbar, the pressure in the second stage is controlled to be 2-4 mbar, and the pressure in the third stage is controlled to be 5-7mbar. The sublimation gas passes through the flow guide pipe 221 and the side gas outlet portion 224 to cause the diameter-reduced growth and the axial growth of the seed crystal 30, respectively. This embodiment still has three-stage growth, the growth temperature is slightly higher than that of the first three embodiments, and the higher temperature can promote the silicon carbide powder 70 to sublimate. Sufficient feed gas is provided to extend the sidewalls of the seed crystal 30 to increase the height of the seed crystal 30.

Example 5

Referring to fig. 10, the present embodiment is different from embodiment 1 only in that,

the silicon carbide crystal growth device 100 of this embodiment, the seed crystal 30 is wholly top-sealed, the open cylindric in bottom, in other words, the seed crystal 30 is the ring form of upper end area lid, a plurality of water conservancy diversion holes 2211 have evenly been seted up to honeycomb duct 221's up end circumference, the quantity of water conservancy diversion hole 2211 on the honeycomb duct 221 up end is six, water conservancy diversion hole 2211 has also evenly been seted up along circumference to the lateral wall of honeycomb duct 221 that is located growth cavity 31, water conservancy diversion hole 2211 has six rows on the honeycomb duct 221 lateral wall, and correspond the setting with water conservancy diversion hole 2211 on the up end.

The silicon carbide gas is sprayed out from the flow guide holes 2211 at the top of the flow guide pipe 221 and the flow guide holes 2211 circumferentially arranged on the side wall, and the gas is uniformly distributed on the inner top wall and the inner side wall of the seed crystal 30, so that the crystal grows on the inner top wall and the inner side wall of the seed crystal 30 simultaneously.

The top end of the draft tube 221 is 2mm lower than the inner top wall of the seed crystal 30, namely the gap between the top end of the draft tube 221 and the top end of the seed crystal 30 is 2mm. The length of the area of the flow guide hole 2211 on the side wall of the flow guide pipe 221 is longer than 30 10mm of the seed crystal, that is, the height L2 of the area formed by the flow guide hole 2211 positioned at the uppermost end of the side wall of the flow guide pipe 221 and the flow guide hole 2211 positioned at the bottom end is 10mm higher than the height L1 of the seed crystal 30.

The process flow comprises the following steps: the second stage crystal growth time is shortened to 100h, the bearing platform 40 descends gradually while the bearing platform rotating lifting shaft 41 rotates, and the descending speed is kept at 0.35mm/h. The top of the draft tube 221 is 12mm lower than the bottom of the seed crystal 30. When the preset descending height is reached, the descending is stopped, the rotation is kept until the crystal growth is finished, and the pressure and the growth stage are the same as those of the embodiment 1.

Example 6

Referring to fig. 11, this embodiment is different from embodiment 5 only in that,

an airflow control member 50 is arranged in the second crucible 20, the structure of the airflow control member 50 is the same as that of the airflow control member 50 in embodiment 2, the length of the diversion hole area of the side wall is longer than 30 mm of the seed crystal, namely, the height L2 of the area formed by the diversion hole 2211 at the uppermost end of the side wall of the diversion pipe 221 and the diversion hole 2211 at the bottom end is 5mm higher than the height L1 of the seed crystal 30.

Referring to fig. 12, the inner rotating shaft 52 is provided inside the draft tube 221 to control the gas flow rate. The growth temperature is unchanged, and the opening degree of the diversion hole can be controlled by adjusting the angle of the rotating shaft. In the first stage of growth, the inner rotating shaft 52 is controlled to open all the top flow guiding holes 2211, so that sufficient gas is provided in the early stage to promote growth. After the first stage is finished, the top diversion hole 2211 is closed, the upper airflow is slowed down, and the growth is maintained in a stable state until the growth is finished.

Comparison of ingot grown by experiment-diameter shrinkage and equal diameter growth process

Comparative experiment

The experiment uses the seed crystals produced from the same crystal ingot, wherein the height of the crystal ingot is 26mm, the diameter of the crystal ingot is 153mm, and the crystal ingot is cut to form a piece of seed crystal with the height of 500 mu m and a ring-shaped seed crystal with the height of 25mm. Two kinds of seed crystals were used for crystal growth comparison experiments, respectively.

Comparative example:

the seed crystal with the height of 500 mu m and the diameter of 153mm grows according to the traditional PVT growth method, the seed crystal is adhered to the top of the first crucible, the silicon carbide powder 70 is placed at the bottom of the first crucible, the induction coil 400 is used for heating, the temperature of the silicon carbide powder 70 is controlled to be 2300-2350 ℃, the sublimation rate is controlled to be 8-10 g/h, the growth time is 100 hours, and the air pressure is controlled to be 5-7mbar.

Examples of the experiments

The seed crystal 30 is a ring-shaped seed crystal with a height of 25mm, the inner diameter of the seed crystal 30 is 152mm, the outer diameter is 153mm, the thickness of the seed crystal 30 is 500 μm, and the silicon carbide crystal growth apparatus 100 and the growth method of example 1 are used for crystal growth.

The relevant test data of the original crystal ingot, the crystal ingot formed by crystal growth of example 1 and the crystal ingot formed by crystal growth of comparative example are shown in table 1:

TABLE 1 comparison of ingot parameters for different processes

As can be seen from the detection data in Table 1, the data of the defects of the boule grown by reducing the diameter of the ring-shaped seed crystal in the embodiment 1 is obviously smaller than the data of the conventional seed crystal growth, and the number of the defects of the boule can be obviously reduced. Meanwhile, through comparison, although the ring-shaped seed crystal and the traditional circular seed crystal are derived from the same crystal ingot, the parameters of the grown crystal ingot are greatly different. The defects of the crystal ingot produced by the traditional seed crystal are more, and the defects of the crystal ingot produced by the annular seed crystal are reduced due to the increase of the height.

Experiment two

The crystal ingot formed by the silicon carbide crystal ingot growing apparatus 100 and the growing method according to example 3, the seed crystal 30, the spliced seed crystal 60, and the crystal ingot parameters formed by the crystal growth are shown in table 2.

TABLE 2 comparison of ingot parameters for seed, splice seed, and seed growth formation for example 3

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Embodiment 3 adopts a scheme of splicing seed crystals, and splicing the spliced seed crystals on the basis of the seed crystals. The raw analytical data for both seeds are shown in table 2. The height of the two seed crystals after splicing is 50mm. The height of the ingot after growth was measured to be 51mm. It can be seen that the total dislocation number of the finally grown ingot is less than 2400/cm ² There was a significant reduction in data from the initial two seeds. And the number of other defects of the grown ingot is less than that of the initial two seed crystals and is far less than that of the ingot grown by the traditional growing method, and the data show that the method can reduce the number of the defects.

Experiment three

The silicon carbide ingot growth apparatus 100 and the silicon carbide ingot growth method according to example 4 were used to grow silicon carbide, and the parameters of the seed crystal 30 and the ingot formed by the growth are shown in table 3.

TABLE 3 comparison of ingot parameters for seed, splice seed, and seed growth formation for example 4

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The scheme adopts the design of annular seed crystals and a side gas outlet part 224, seed crystal data and ingot data finally grown. The diameter of the seed crystal 30 is 153mm, the height of the seed crystal is 25mm, the height of the crystal ingot reaches 32mm after the final growth, the experimental scheme of side air outlet is adopted, and the main purpose is that the height of the seed crystal 30 can be prolonged by ventilating the air outlet 2241 on the side part while the seed crystal 30 grows, and the crystal ingot with larger height is obtained. Experimental data show that the experimental method can effectively prolong the height of the ingot. And by contrast, the crucible is designed to increase the height of the ingot and reduce the defects of ingot growth. The defect reduction can reach more than 50 percent and is far lower than the defects of the crystal ingot grown by the traditional growing method.

To sum up, the utility model discloses a growth device of preparation carborundum crystal has following advantage:

first aspect, the utility model discloses a new crystal growth mode adopts the radius of contraction growth in annular seed crystal, thereby microtube in the seed crystal and defects such as dislocation can't be inherited owing to the difference of growth mode to reduce crystal defect, sublimed gas is used for growing by the seed crystal parcel, reduces the loss of sublimed gas, improves the utilization ratio of raw materials 6% -10%. Meanwhile, the height of the grown silicon carbide crystals is larger for the same weight of raw materials.

In the second aspect, the design of the guide cover and the airflow channel of the second crucible, the silicon carbide gas directly enters the growth cavity of the seed crystal through the airflow channel, so that the sublimation gas can be uniformly dispersed on the surface of the seed crystal, the crystal growth efficiency is improved, and the crystal can achieve the purpose of uniform growth.

The outside heat preservation design at third aspect seed crystal position, the part from the bottom up external diameter that the heat preservation is located the seed crystal outside reduces gradually, can establish the regional temperature gradient of seed crystal in axial direction, and the seed crystal from the bottom up temperature reduces gradually promptly, and the position temperature that heat preservation 200 is thicker is higher more, can grow smoothly at the growth face when carborundum gas gets into the seed crystal region, can establish the regional temperature gradient of seed crystal in axial direction, can grow smoothly at the growth face when gas gets into the seed crystal region.

The fourth aspect, because the kuppe adopts the graphite material, consequently, certain effect of generating heat has, the honeycomb duct of kuppe stretches into in the growth cavity to the seed crystal, the honeycomb duct is by the central axis of seed crystal to give off the heat all around, the heat that the honeycomb duct gived off can provide certain heat to seed crystal central direction, thereby reduce radial temperature gradient, footpath, the even undergauge of crystal grows, whole circumference all is in the same temperature (draw the circle on the horizontal plane with the one point on the central axis of seed crystal as the centre of a circle, the temperature of all points on the same radius circle is the same), can reduce the inside thermal stress of crystal, reduce the crystal convexity, reduce crystal defects.

In the fifth aspect, the use of the annular seed crystal can allow a plurality of splicing seed crystals to be used simultaneously for connection, or the outer edge of the guide pipe vertically extends upwards along the circumference to form a side gas outlet part, and the silicon carbide gas is grown at the bottom of the annular seed crystal after coming out through the side gas outlet part, so that the height of the annular seed crystal is increased, and when the annular seed crystal is reduced in diameter and grows, the height is increased, the second crucible moves downwards, the newly grown annular seed crystal is further reduced in diameter and grows, and the crystals with large height can be grown in two modes.

And in the sixth aspect, a novel crucible structure is adopted, and the states of the crucible in the growth process are controlled by adopting the first crucible, the second crucible, the flow guide cover, the crucible main body, the inner rotating shaft and the outer rotating bearing platform, so that the crystal is always in a good growth environment, the crystal defects are reduced, and the crystal quality is improved. The design of the guide holes and the inner rotating shaft on the guide pipe can control the overflow rate of the sublimated gas, so that the crystal growth speed is controlled to be in an ideal state, and the purpose of uniform crystal growth is achieved.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description of the present specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. A growing apparatus for producing a silicon carbide crystal, comprising:

a first crucible defining a reaction chamber;

the seed crystal is arranged in the reaction cavity and defines a growth cavity extending in the vertical direction;

the second crucible, the second crucible set up in the reaction chamber, place the carborundum powder in the second crucible, the growth cavity orientation carborundum powder one side is opened, the second crucible extends to in the growth cavity, and extend to the part of growth cavity is equipped with the intercommunication the water conservancy diversion hole of growth cavity, the sublimed carborundum vapour of carborundum powder passes through the water conservancy diversion hole enters into in the growth cavity the internal surface undergauge growth of seed crystal goes out the carborundum crystal.

2. The growth apparatus for producing a silicon carbide crystal according to claim 1, wherein the seed crystal comprises a first seed crystal portion having an annular cylindrical structure, and the growth cavity penetrates the first seed crystal portion in the up-down direction.

3. The growth apparatus for producing a silicon carbide crystal as recited in claim 2 wherein the seed crystal further comprises a second seed portion sealingly disposed at an upper end of the first seed portion, the first and second seed portions together defining the growth cavity.

4. The growth device for preparing the silicon carbide crystal as claimed in claim 1, wherein the second crucible comprises a crucible main body and a flow guide cover, the upper end of the crucible main body is detachably connected with the flow guide cover, the crucible main body is used for containing the silicon carbide powder, and the flow guide cover forms an air flow channel and extends into the growth cavity.

5. The growth device for preparing silicon carbide crystals according to claim 4, wherein the guide hood comprises a guide pipe and a guide pipe, the guide pipe is detachably connected with the crucible main body, the radial sectional area of the guide pipe is smaller than that of the crucible main body, the guide pipe extends into the growth cavity of the seed crystals, and the guide holes are formed in the guide pipe.

6. The growth apparatus for producing silicon carbide crystals according to claim 5, wherein a gas flow control member is disposed in the second crucible and rotatably disposed in the gas flow channel for controlling the flow of silicon carbide gas from the second crucible into the growth cavity;

the gas flow control piece comprises a baffle plate assembly and an inner rotating shaft, the inner rotating shaft penetrates through the crucible main body and extends into the upper portion of the flow guide cover, the top of the inner rotating shaft is fixedly connected with the baffle plate assembly, the baffle plate assembly and the flow guide hole are correspondingly arranged, and the inner rotating shaft is rotatable so that the baffle plate assembly can shield or open the flow guide hole.

7. The growth apparatus for preparing silicon carbide crystals according to claim 5, wherein the guide tube is in the shape of an inverted cone, and the guide tube is located at the center of the upper end of the guide tube.

8. The growing device for preparing the silicon carbide crystals according to claim 5, wherein the part of the guide tube opposite to the seed crystals protrudes upwards to form a side air outlet part, the side air outlet part is annular, air outlets are uniformly formed in the upper end surface of the side air outlet part, the inner side wall of the side air outlet part extends upwards to form an annular side baffle, and the outer diameter of the side baffle is equal to the inner diameter of the seed crystals.

9. The growth device for preparing the silicon carbide crystals according to claim 7, wherein one end of the seed crystal close to the silicon carbide powder is connected with at least one spliced seed crystal, the spliced seed crystal is in an annular cylindrical structure, the inner diameter of the spliced seed crystal is the same as that of the seed crystal, and the outer diameter of the spliced seed crystal is the same as that of the seed crystal.

10. The growing device for preparing silicon carbide crystals according to claim 6, wherein a plurality of rows of the diversion holes are formed in the side wall of the diversion cover at intervals along the circumference, the baffle plate assembly comprises a plurality of baffle plates which are circumferentially arranged at intervals by taking the center of the upper end face of the inner rotating shaft as a circle center, the baffle plate assembly vertically extends downwards at the edge of each baffle plate to form a side wall baffle plate, the side wall baffle plate is used for shielding the diversion holes in the side wall of the diversion pipe, the side wall baffle plate at least extends to the lower edge of the diversion hole at the bottommost part of the side wall of the diversion pipe, and the baffle plates and the diversion holes are arranged in a one-to-one correspondence manner.

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