CN110079863B

CN110079863B - Reactor for crystal growth

Info

Publication number: CN110079863B
Application number: CN201910325375.8A
Authority: CN
Inventors: 李加林; 张红岩; 窦文涛; 宗艳民; 李斌; 高超; 刘家朋; 李长进; 李宏刚; 孙元行; 刘鹏飞
Original assignee: Sicc Co ltd
Current assignee: Shandong Tianyue Advanced Technology Co Ltd
Priority date: 2019-04-22
Filing date: 2019-04-22
Publication date: 2020-07-14
Anticipated expiration: 2039-04-22
Also published as: CN110079863A

Abstract

The application relates to a reactor for crystal growth, belonging to the field of crystal material preparation. The reactor for crystal growth includes: a crucible assembly, comprising: the crucible comprises a crucible main body, a crucible cover and a spiral clapboard component arranged in the crucible main body, wherein the raw materials loaded in the crucible main body are sublimated and at least partially pass through a spiral airflow channel formed by the spiral clapboard component to grow crystals; a supporting component and a heating component, and the crucible assembly can also rotate. The reactor changes the traditional gas phase transmission mode, and converts the traditional vertical upward transmission into spiral upward transmission, thereby realizing effective blocking of large-particle impurities in the crystal growth process, reducing the defect density in the crystal and improving the crystal quality; the gas phase is not difficult to transmit upwards, the excessive growth temperature is not needed, and the energy consumption is reduced; the vacuum single crystal growth device can control the gas phase transmission under vacuum, the single crystal growth rate under vacuum is high, the growth temperature is low, the gas phase can be orderly transmitted upwards, the grown crystal has few defects, and the cost is reduced and the efficiency is improved.

Description

Reactor for crystal growth

Technical Field

The application relates to a reactor for crystal growth, belonging to the field of crystal material preparation.

Background

Silicon carbide is a typical wide bandgap semiconductor material and is one of the representatives of the third generation of semiconductor materials following silicon, gallium arsenide. The silicon carbide material has excellent characteristics of high thermal conductivity, high breakdown field strength, high saturated electron mobility and the like, and becomes one of hot materials for preparing high-temperature, high-frequency, high-power and anti-radiation devices.

The growth process of the PVT method for growing the silicon carbide single crystal is carried out in a closed graphite crucible, so that the growth environment is in a carbon-rich atmosphere at high temperature.

At present, a graphite filter screen is arranged on a silicon carbide gas phase transmission path to play a role in isolating large particle impurities from being transmitted upwards in a main flow direction for solving the defect of the large particle impurities in the silicon carbide single crystal. Chinese patent application CN 207498521U discloses a carborundum single crystal growth device of promotion quality, including graphite crucible, graphite lid and the soft felt heat preservation of graphite, the graphite lid is located graphite crucible top and seals graphite crucible, the inboard central salient region of graphite lid bonds there is the seed wafer, the cladding of the soft felt heat preservation of graphite crucible around, top, bottom, the carborundum powder has been placed in the graphite crucible, the graphite support ring is erect to the region between carborundum powder and the seed wafer in the graphite crucible, install the draft tube on the graphite support ring, the metal filter piece of draft tube internal fixation one deck or multilayer, evenly distributed has the through-hole in the metal filter piece. The utility model discloses high temperature resistance metal filter and draft tube are installed to the space between raw materials and the seed crystal in the crucible, can effectively filter carbon impurity, avoid forming carbon parcel thing in the crystal growth process, and then cause the production of defects such as micropipe, dislocation, generate high-quality carborundum single crystal. This patent application scheme can effectively control the density of large granule impurity defect in the silicon carbide single crystal, but the existence of graphite filter screen often can cause the degree of difficulty of the transmission of silicon carbide gaseous phase upwards, need the stability that the gaseous phase just can realize the seed crystal transmission to the increase temperature, and the improvement of temperature then can greatly increased in the crystal stress and the output probability of other defects, the quality of silicon carbide single crystal can't obtain guaranteeing. In the process of crystal growth, the gas phase under vacuum growth of the traditional gas phase transmission mode cannot be effectively controlled, the growth rate of the single crystal is extremely high, the crystal quality is extremely poor, and the defects of micropipes, polytypes, dislocations and the like are obviously increased.

Disclosure of Invention

In order to solve the problems, the application provides a reactor for crystal growth, changes the traditional gas phase transmission mode of preparing crystals by a PVT method, and converts the traditional vertical upward transmission into spiral upward transmission, thereby realizing effective blocking of large-particle impurities in the crystal growth process, reducing the defect density in the crystals and improving the crystal quality; the gas phase is not difficult to transmit upwards, the excessive growth temperature is not needed, and the energy consumption is reduced; the vacuum single crystal growth device can control the gas phase transmission under vacuum, the single crystal growth rate under vacuum is high, the growth temperature is low, the gas phase can be orderly transmitted upwards, grown crystal defects are few, cost is reduced, and efficiency is improved.

The reactor for crystal growth comprises: a crucible assembly, comprising: the crucible comprises a crucible main body, a crucible cover and at least one spiral clapboard component arranged in the crucible main body, wherein the raw materials loaded in the crucible main body are sublimated and at least partially pass through a spiral airflow channel formed by the spiral clapboard component to grow crystals; a support member located inside the crucible cover and adapted to support a growing crystal; and a heating member adapted to maintain the crucible assembly at a temperature at which a crystal is grown.

Optionally, the crucible assembly is rotatable. Preferably, the rotation speed of the crucible assembly is 10-200 rpm/h.

Optionally, at least a portion of the diameter of the spiral baffle plate assembly is the same as the inside diameter of the crucible body at the same height thereof. Preferably, the lower portion of the crucible body has a smaller diameter than the upper portion.

Preferably, the spiral partition plate assembly and the inner wall of the crucible body are configured to form a uniform spiral gas flow channel.

Optionally, the axis of the spiral baffle plate assembly is parallel to the axis of the crucible body.

Optionally, the spiral baffle assembly comprises 2-6 spiral vanes. Preferably, the spiral diaphragm assembly comprises 4 spiral blades.

Optionally, the spiral partition assembly is a spiral shaft including a spiral blade, the spiral partition includes a spiral blade having a certain thickness, and a diameter ratio of the spiral blade to a shaft portion of the spiral shaft is greater than 2: 1.

preferably, the pitch of the helical blades is the same.

Optionally, the spiral baffle assembly comprises a feed zone spiral baffle disposed in the feed zone.

Preferably, the spiral angle of the spiral clapboard in the raw material area is 60-90 degrees, and the angle of a single leaf surface in the vertical direction is 90-360 degrees. The angle is matched with the rotation of the crucible, so that the spiral rising of the silicon carbide gas phase can be realized, and the gas phase transmission cannot be greatly hindered.

Optionally, the spiral baffle assembly further comprises a gas phase transport zone spiral baffle disposed in the gas phase transport zone.

Preferably, the helical angle of the helical baffle of the gas phase transmission zone is 60-90 degrees, and the angle of the single leaf surface in the vertical direction is 60-180 degrees. The angle can better block large-particle impurities, and the crystal growth temperature does not need to be increased.

Optionally, the height ratio of the spiral partition plate of the raw material zone to the spiral partition plate of the gas phase transmission zone is as follows: 48-180:12-45.

Optionally, the spiral partition plate of the raw material zone comprises 2-6 spiral blades, and the spiral partition plate of the gas phase transmission zone comprises 2-6 spiral blades.

Optionally, the ratio of the distance from the gas phase transmission zone spiral partition to the raw material, the length of the gas phase transmission zone spiral partition and the distance from the gas phase transmission zone spiral partition to the seed crystal is as follows: 20-80:12-45:68-245. Optionally, the spiral baffle assembly comprises a gas phase transport zone spiral baffle disposed in a gas phase transport zone.

Optionally, the spiral baffle assembly further comprises a feedstock region spiral baffle disposed in the feedstock region.

Optionally, the spiral baffle of the gas phase transmission zone and the spiral baffle of the raw material zone have different spiral directions. Preferably, the crucible assembly rotates in the direction opposite to the spiral direction of the spiral partition plate of the raw material region and in the same direction as the spiral partition plate of the gas phase transfer region.

The position of the spiral clapboard of the gas phase transmission area is approximately on the upper surface of the crucible body for loading raw materials and the gas phase transmission area on the lower surface of the crystal after the crystal growth is finished; the source material region is generally the region within the crucible body in which the source material is disposed.

Optionally, the crucible assembly is surrounded by a heat insulating material, the crucible assembly is inserted into a quartz container, the heating element is of an induction type, and the material of the crucible assembly comprises graphite.

Preferably, the crucible and the insulating material are rotatable. Through the directional rotation of raw materials district spiral baffle and crucible subassembly, the route of upwards transmitting raw materials district carborundum gaseous phase is converted into spiral upwards transmission by traditional perpendicular upwards transmission, combines gaseous phase transmission district spiral baffle to carry out the check to the gaseous phase of upwards transmitting and filters, prevents that large granule impurity from transmitting to the crystal orientation and getting into the crystal, reduces the defect density of carborundum single crystal. Preferably, the spiral direction of the spiral partition plate in the raw material zone is different from that of the spiral partition plate in the gas phase transfer zone.

According to another aspect of the present application, there is provided the use of a reactor for crystal growth in the preparation of crystals of silicon carbide or of a nitride of a triple element.

Benefits that can be produced by the present application include, but are not limited to:

1. according to the reactor for crystal growth, the spiral partition plate assembly is arranged in the crucible main body of the reactor, the traditional silicon carbide gas phase transmission mode is changed, the traditional vertical upward transmission mode is converted into the spiral upward transmission mode, the spiral partition plate assembly performs blocking filtration on the upward transmitted gas phase, large-particle impurities are prevented from being transmitted to the crystal direction and entering the crystal, and the defect density of single crystals such as silicon carbide and the like is reduced; not only can carry out effectual check to large granule impurity and keep off, can not cause gaseous phase upward transmission difficulty again, need not too high growth temperature, reduce the energy consumption.

2. Under the traditional gas phase transmission mode, the gaseous phase under the vacuum growth can not be effectively controlled, the single crystal growth rate is extremely fast and the crystallization quality is extremely poor, the defects such as micropipes, polytype, dislocation are obviously increased, the reactor for crystal growth provided by the application plays a role in obviously inhibiting and regulating the gaseous phase transmission rate while changing the gaseous phase transmission path through the directional rotation of two spiral clapboards and a crucible assembly, the control effect on the gaseous phase transmission under the vacuum can be played, the single crystal growth rate under the vacuum is fast and the gaseous phase can be orderly upwards transmitted, the defects of the grown crystal are fewer, the vacuum low-temperature rapid growth is realized, the growth temperature is reduced, the growth time is shortened, the energy is saved, the cost is reduced, and the effect is increased.

3. According to the reactor for crystal growth, the spiral partition plate assembly is in full contact with the inner wall of the crucible main body, so that heat conduction in the crucible main body is more uniform, a temperature field is more stable, and the crystal quality is improved; the spiral partition plate in the raw material area is in full contact with the raw materials, the outer wall of the spiral partition plate is in full contact with the inner wall of the crucible to conduct heat inwards, so that the silicon carbide raw materials are heated more uniformly, the raw material edge carbonization is reduced, and the gas phase conduction is more uniform and ordered.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic view of a reactor for crystal growth according to an embodiment of the present application.

FIG. 2 is a schematic cross-sectional view of a crucible assembly according to an embodiment of the present application.

FIG. 3 is a schematic top view of the spiral baffle of the gas phase transport zone of FIG. 2.

FIG. 4 is a schematic perspective view of the spiral baffle of the vapor transport zone of FIG. 2.

FIG. 5 is a schematic perspective view of the spiral baffle of the vapor transport zone of FIG. 2.

FIG. 6 is a schematic front view of the spiral baffle of the vapor transport zone of FIG. 2.

Fig. 7 is a schematic perspective view of the spiral baffle of the feed zone of fig. 2.

Fig. 8 is a schematic perspective view of the spiral baffle of the feed zone of fig. 2.

Detailed Description

In order to more clearly explain the overall concept of the present application, the following detailed description is given by way of example in conjunction with the accompanying drawings.

So that the manner in which the above recited objects, features and advantages of the present application can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.

In addition, in the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present application.

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 application, "a plurality" means two or more unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; 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 application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., 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 application. 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.

The analysis method in the examples of the present application is as follows:

1. microscopic examination was carried out using a microscope model BX51 from O L YMPUS.

2. The polytype test used a model HR800 Raman spectrometer from HORIBA.

3. The dislocation test was carried out using a microscope model BX51 from O L YMPUS after etching with potassium hydroxide.

4. The inclusion test used a microscope model BX51 from O L YMPUS.

Unless otherwise specified, the raw materials, catalysts and gases in the examples of the present application were all purchased commercially, wherein the purity of the silicon carbide raw material was 99.99%, and the purity of the high-purity inert gas (Ar or He) was more than 99.99%.

Referring to fig. 1, the reactor of the present application can be used to prepare a silicon carbide single crystal or a schematic cross-sectional view of crystal growth of a group-iii nitride such as gallium nitride or aluminum nitride, and is particularly suitable for growing a silicon carbide single crystal by a physical vapor transport method (abbreviated as PVT method).

The crystal growth reactor includes a crucible assembly in which crystal growth occurs. The reactor in fig. 1 includes a crucible assembly; a support member located inside the crucible cover 3 and adapted to support a growing crystal; and a heating member adapted to maintain the crucible assembly at a temperature at which the crystal is grown.

In one embodiment, referring to fig. 2, the crucible assembly includes a crucible main body 2, a crucible cover 3, and a spiral barrier rib assembly 4, a support member of an inner side of the crucible cover 3 may be provided with a seed crystal 31, the spiral barrier rib assembly 4 is provided in the crucible main body 2, and the spiral barrier rib assembly 4 may be configured to form a spiral gas flow path. The number of the spiral partition plate assemblies 4 is at least one, and the number of the spiral partition plate assemblies 4 in the embodiment of the crucible assembly shown in fig. 2 is 2. The upper end surface of the spiral clapboard component 4 in the crucible body 2 is at least not higher than the position of the crystal face after the raw material is grown.

The spiral partition plate assembly 4 may be fixed to the crucible main body 2 by a chuck provided at an inner side wall of the crucible main body 2, or may be placed in the crucible main body 2. The upper portion of the spiral spacer assembly 4 is not in contact with the seed crystal 31. Preferably, the length direction of the spiral partition plate assembly 4 is parallel to the length of the crucible body 2.

The diameter of the spiral partition plate assembly 4 in the embodiment shown in FIG. 2 is the same as the inner diameter of the crucible main body 2 at the same height. In an embodiment not shown, the diameter of the spiral partition plate assembly 4 and the inner diameter of the crucible main body 2 at the same height thereof may be different, or a part of the diameter of the spiral partition plate assembly 4 and the inner diameter of the crucible main body 2 at the same height thereof may be different. The spiral clapboard component 4 is fully contacted with the crucible main body, so that the heat transfer in the crucible is more uniform, and the crystal quality is improved.

As a preferred embodiment, the configuration of the spiral partition plate assembly 4 and the inner wall of the crucible main body 2 includes forming a single spiral gas flow passage. Referring to fig. 2, the number of the spiral partition plate assemblies 4 is 2, and the configuration of the spiral partition plate assemblies 4 and the inner wall of the crucible body 2 includes the formation of 2 single spiral gas flow passages, and so on. The preferred single spiral gas flow channel is a uniform channel, i.e. the inner diameter of the single spiral channel is uniform.

Further, the spiral partition plate assembly 4 may be a hollow spiral blade or a spiral shaft including the spiral blade 43, preferably the spiral shaft, as shown in fig. 3, the spiral partition plate assembly 4 includes 2 to 6 spiral blades 43, the pitch of the spiral blades 43 may be different, and preferably the pitch of the spiral blades 43 is the same.

Referring to fig. 1 and 2, the spiral barrier plate assembly 4 includes a gas phase transfer region spiral barrier plate 41 disposed in a gas phase transfer region and a raw material region spiral barrier plate 42 disposed in a raw material region, referring to fig. 3 to 6, a spiral angle α of the gas phase transfer region spiral barrier plate 41 is 60 ° to 90 °, which can better block large particle impurities and does not require an increase in a nucleation temperature, a single blade face angle β in a vertical direction of the gas phase transfer region spiral barrier plate is 60 ° to 180 °, further optimizing an efficiency of the gas phase transfer region spiral barrier plate for blocking large particle impurities, and referring to fig. 7 and 8, a spiral angle α of the raw material region spiral barrier plate 42 is 60 ° to 90 °, which can realize a spiral ascent of a silicon carbide gas phase in cooperation with a rotation of a crucible and does not cause much hindrance to gas phase transfer, a single blade face angle β in a vertical direction of the raw material region spiral barrier plate is 90 ° to 360 °, a gas phase transfer region spiral barrier plate 41 is different from a spiral direction of the raw material region spiral barrier plate 42, which can make it possible to more effectively block large particle.

In order to effectively block large particles and not cause large obstruction to gas phase transmission, the height setting ratio of the spiral partition plate 42 in the raw material area to the spiral partition plate 41 in the gas phase transmission area is as follows: 48-180:12-45, the spiral baffle plate 42 of the raw material zone comprises 2-6 spiral blades, and the spiral baffle plate 41 of the gas phase transmission zone comprises 2-6 spiral blades.

The ratio of the distance from the spiral clapboard 41 of the gas phase transmission area to the raw material, the height of the spiral clapboard 41 of the gas phase transmission area and the distance from the spiral clapboard 41 of the gas phase transmission area to the seed crystal 31 is as follows: 20-80:12-45:68-245. In the preferred embodiment, the height of the raw material is about 1/3, the bottom of the spiral partition 41 of the gas phase transmission zone is fixed at about 1/2 of the crucible body 2, the height of the spiral partition 41 of the gas phase transmission zone is about 1/10, the height of the spiral partition 42 of the raw material zone is slightly lower than the height of the raw material, and the spiral partition 42 of the raw material zone is just buried in the raw material. Preferably, the ratio of the height of the feedstock to the height of the feedstock zone spiral partition 42 is from 1:0.7 to 0.98. When the spiral partition plate 42 in the raw material area is in full contact with the inner wall of the crucible main body 2, the spiral partition plate 42 in the raw material area is in full contact with the raw material, the spiral partition plate 42 in the raw material area is in full contact with the inner wall of the crucible main body 2 to conduct heat inwards, so that the raw material is heated more uniformly, the raw material edge carbonization is reduced, the crystal quality is improved, and for example, the raw material can be silicon carbide powder.

The crucible assembly is surrounded by a thermal insulation material 5, preferably graphite fibers such as graphite felt; the crucible assembly is inserted into the quartz container 6; the heating member 7 is of an induction type, such as a heating coil; the crucible assembly is made of graphite.

In a preferred embodiment, the crucible assembly and the heat insulating material 5 are rotatably disposed in the quartz container 6. Optionally, the crucible assembly surrounding the thermal insulation material 5 is arranged on the tray 8, the tray 8 is fixed by a tray rod 81 penetrating through the quartz container 6, and the bottom end of the tray rod 81 is driven by the motor 9 to rotate so as to rotate the tray 8 and drive the crucible assembly and the thermal insulation material 5. The reactor is fixedly placed by means of support plates 82 and support plates 83. In order to enhance the heat-insulating effect in the reactor, a screw pipe is provided on the tray rod 81 outside the quartz container 6.

It is preferable that the spiral direction of the spiral partition 42 of the raw material zone and the spiral partition 41 of the gas phase transfer zone are different. The spiral direction of the spiral partition plate 42 in the raw material area is the same as the rotation direction of the crucible assembly, the path of upward transmission of the raw material area such as silicon carbide gas phase is converted from the traditional vertical upward transmission into the spiral upward transmission, the spiral direction of the spiral partition plate 41 in the gas phase transmission area is different from the spiral direction of the spiral partition plate 42 in the raw material area, so that the spiral partition plate 41 in the gas phase transmission area performs lattice filtration on the upward transmitted gas phase, large-particle impurities are prevented from being transmitted into crystals in the crystal direction, and the defect density of the grown crystals such as silicon carbide single crystals is reduced.

In the traditional gas phase transmission mode of PVT crystal growth, the gas phase under vacuum growth cannot be effectively controlled, the growth rate of the single crystal is extremely high, the crystal quality is extremely poor, and the defects of micropipes, polytypes, dislocation and the like are obviously increased. This application is through set up gaseous phase transmission district spiral baffle and raw materials district spiral baffle in the crucible main part to and the directional rotation of crucible subassembly, play obvious suppression regulation and control effect to gaseous phase transmission rate when changing gaseous phase transmission route, can play the control action to gaseous phase transmission under the vacuum, the single crystal growth rate under the vacuum is very fast and gaseous phase can upwards transmit in order, the defect is less, realizes vacuum low temperature fast growth, reduce growth temperature, reduce growth time, reduce cost and improve effect.

A method for preparing silicon carbide single crystal comprises the steps of sublimating raw materials in a crucible main body, conveying the raw materials to the surface of seed crystal through a spiral airflow channel formed by at least one spiral partition plate in a gas phase mode, and growing crystal to obtain the silicon carbide crystal. The preparation method can use any one of the reactors to achieve the purpose, namely, the spiral partition plate is arranged in the crucible main body, so that the effect of blocking large particles in gas phase transmission can be achieved, the defect density can be reduced, and the quality of the prepared silicon carbide crystal is improved.

Preferably, a production method for producing a silicon carbide single crystal, comprising the steps of:

(1) placing a high-purity graphite crucible filled with silicon carbide powder, a raw material area spiral partition plate, a transmission area spiral partition plate and seed crystals in a single crystal growth furnace body and sealing, wherein the height of the raw material is slightly higher than that of the raw material area spiral partition plate, so that the raw material area spiral partition plate is completely buried in the raw material;

(2) the furnace body is vacuumized to 10^-6Introducing high-purity inert gas to 300-500mbar below mbar, repeating the process for 2-3 times, and finally vacuumizing the furnace body to 10-^-6mbar below;

(3) introducing high-purity inert gas into the furnace body, increasing the pressure to 10-100mbar within 1-3h, and continuously introducing the high-purity inert gas while keeping the pressure unchanged;

(4) a first crystal growth stage: under the condition of keeping the pressure unchanged, the temperature in the furnace body is increased to 1950 and 2150 ℃ for 3-5h, and the growth time is 5-10 h;

(5) a second crystal growth stage: keeping the growth temperature unchanged, and reducing the pressure in the furnace body to vacuum 10 within 3-5h^-4Keeping the mbar below the mbar unchanged, and simultaneously directionally rotating the crucible assembly, wherein the rotating direction of the crucible assembly is consistent with the spiral direction of the spiral clapboard in the raw material area, the rotating speed is 10-200 revolutions per hour, the position of the crucible in the vertical direction is unchanged, and the growth time is 30-100 hours;

(6) and opening the furnace body after the growth of the single crystal is finished, and taking out the graphite crucible to obtain the silicon carbide single crystal with low defect density.

The reactor used in the preparation method is a preferred embodiment among embodiments of the present application, with reference to fig. 1.

The silicon carbide single crystal 1# -3# and the comparative silicon carbide single crystal D1# -D4# were prepared according to the above-mentioned methods, and the differences from the above-mentioned methods in the specific preparation methods are shown in Table 1.

TABLE 1

The structural defects of the prepared silicon carbide single crystal 1# -3# and the comparative silicon carbide single crystal D1# -D4# such as micropipes, polytypes, dislocations, inclusions and the like are detected, and the detection results are shown in Table 2.

TABLE 2

From the results of tables 1 and 2, it can be seen that:

1. the silicon carbide single crystal 1# is a silicon carbide single crystal grown after a group of crystal growth parameters are optimized and combined, the defects of micropipes, polytypes, inclusion bodies and the like do not appear, and the dislocation density is also maintained at 1000/cm²The content of the compound is less than the content of the compound;

2. the rotating speed of the crucible assembly of the silicon carbide single crystal 2# is adjusted to 30 revolutions per hour from 80 revolutions per hour on the basis of the silicon carbide single crystal 1#, and as can be seen from the table 2, the related defects are not obviously increased, and the single crystal quality is high;

3. the spiral direction of the spiral partition plate in the raw material region and the spiral direction of the spiral partition plate in the gas phase region of the silicon carbide single crystal 3# are set to be the same on the basis of the silicon carbide single crystal 1# so that the density of the produced single crystal micropipe is obviously improved, the inclusion defect starts to appear, and the spiral directions of the two spiral partition plates on the surface are the same, which is not beneficial to the control of the micropipe and the inclusion defect;

4. compared with the silicon carbide single crystal D1#, the rotating speed of the crucible assembly is adjusted from 80 revolutions per hour to 0 revolutions per hour on the basis of the silicon carbide single crystal 1#, and according to the table 2, the density of the produced single crystal micropipe is basically the same as that of the silicon carbide single crystal 3#, but the inclusion defect is obviously aggravated, and the yield of the inclusion defect can be obviously inhibited through the directional rotation of the crucible assembly and the combination of the two spiral partition plates;

5. compared with the silicon carbide single crystal D2# which does not use a two-step crystal method to grow the silicon carbide single crystal, the growth time of the single crystal is doubled, the growth temperature is increased by 50 ℃, and each defect index is greatly increased, which shows that the quality of the single crystal of the silicon carbide single crystal grown under the conditions of more time consumption and higher energy consumption is greatly reduced;

6. compared with the silicon carbide single crystal D3#, D4#, the spiral partition board in the raw material area and the spiral partition board in the gas phase transmission area are further removed on the basis of the silicon carbide single crystal D2#, each defect index continues to increase obviously, which shows that the quality of the single crystal cannot be controlled without the barrier filtration effect of the spiral partition board on the gas phase.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A reactor for crystal growth, the reactor comprising: a crucible assembly, comprising: the crucible comprises a crucible main body, a crucible cover and at least one spiral clapboard component arranged in the crucible main body, wherein the raw materials loaded in the crucible main body are sublimated and at least partially pass through a spiral airflow channel formed by the spiral clapboard component to grow crystals; a support member located inside the crucible cover and adapted to support a growing crystal; and a heating member adapted to maintain the crucible assembly at a temperature at which a crystal is grown;

the spiral baffle plate component comprises a raw material area spiral baffle plate arranged in a raw material area and a gas phase transmission area spiral baffle plate arranged in a gas phase transmission area.

2. The reactor of claim 1, wherein the crucible assembly is rotatable.

3. The reactor of claim 1, wherein at least a portion of the diameter of the spiral baffle assembly is the same as the inside diameter of the crucible body at the same height.

4. The reactor for crystal growth of claim 3, wherein the configuration of the spiral baffle assembly and the inner wall of the crucible body includes forming a uniform spiral gas flow channel.

5. The reactor for crystal growth of claim 1, wherein an axis of the spiral baffle assembly is parallel to an axis of the crucible body.

6. The reactor for crystal growth of claim 1, wherein the spiral baffle assembly comprises 2-6 spiral vanes.

7. The reactor for crystal growth of claim 1, wherein the spiral baffle assembly is a spiral shaft comprising spiral blades.

8. The reactor for crystal growth of claim 7, wherein the pitch of the helical blades is the same.

9. The reactor for crystal growth of any one of claims 1 to 8, the helical angle of the helical baffle of the feed zone being 60 ° to 90 °, the single leaf surface angle in the vertical direction being 90 ° to 360 °.

10. The reactor for crystal growth as claimed in any one of claims 1 to 8, wherein the helical angle of the gas phase transport zone helical baffle is 60 ° to 90 °, and the single leaf surface angle in the vertical direction is 60 ° to 180 °.

11. The reactor for crystal growth of claim 9, the helical angle of the gas phase transport zone helical baffle is 60 ° to 90 °, and the single leaf surface angle in the vertical direction is 60 ° to 180 °.

12. The reactor for crystal growth of claim 10, wherein the helical baffle of the vapor transport zone has a helical direction different from the helical baffle of the feed zone.

13. The reactor for crystal growth of claim 11, wherein the helical baffle of the vapor transport zone has a helical direction different from the helical baffle of the feed zone.

14. The reactor for crystal growth of any of claims 1-8, wherein the crucible assembly is surrounded by a thermal insulation material, the crucible assembly is inserted into a quartz container, the heating element is induction type, and the material of the crucible assembly comprises graphite.

15. The reactor for crystal growth of claim 14, wherein the crucible assembly and the insulating material are rotatable.

16. The reactor of claim 9, wherein the crucible assembly is surrounded by a thermal insulation material, the crucible assembly is inserted into a quartz container, the heating element is induction type, and the material of the crucible assembly comprises graphite.

17. The reactor for crystal growth of claim 16, wherein the crucible assembly and the insulating material are rotatable.

18. The reactor of claim 10, wherein the crucible assembly is surrounded by a thermal insulation material, the crucible assembly is inserted into a quartz container, the heating element is induction type, and the material of the crucible assembly comprises graphite.

19. The reactor for crystal growth of claim 18, wherein the crucible assembly and the insulating material are rotatable.

20. A reactor for crystal growth as claimed in any one of claims 11 to 13, wherein the crucible assembly is surrounded by a heat insulating material, the crucible assembly is inserted into a quartz vessel, the heating element is of the induction type, and the material of the crucible assembly comprises graphite.

21. The reactor for crystal growth of claim 20, wherein the crucible assembly and the insulating material are rotatable.