Crystal growth apparatus

Abstract

The application provides a crystal growth device, and relates to the technical field of crystal preparation.The crystal growth device comprises a crucible body, a crucible cover, a separator and a heating device.The crucible body comprises a crucible bottom wall and a crucible side wall connected with each other, and the crucible bottom wall and the crucible side wall form a cavity.The crucible cover is arranged on the side of the crucible side wall opposite to the crucible bottom wall, and the side of the crucible cover facing the crucible bottom wall is used for arranging a first seed crystal.The separator is arranged in the cavity, the side of the separator facing the crucible bottom wall is used for arranging a second seed crystal, the side of the separator facing the crucible cover is used for carrying a first silicon carbide powder, and the crucible bottom wall is used for carrying a second silicon carbide powder.The heating device is arranged on the outer periphery of the crucible side wall, is used for sublimating the first silicon carbide powder and the second silicon carbide, and is used for moving the sublimated growth atmosphere to the first seed crystal and the second seed crystal for crystallization.Thus, at least two silicon carbide crystals can be obtained in one growth cycle, and the production capacity is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crystal preparation, in particular to a crystal growth device. BACKGROUND

[0002] Silicon carbide (SiC) is a representative material of the third generation of wide band gap semiconductor materials, which has a large band gap, a high critical breakdown field strength, a high carrier saturation migration speed, a high thermal conductivity, and excellent chemical stability. Based on the above-mentioned excellent physical and chemical properties, SiC has a wide application in the fields of microelectronics and optoelectronics.

[0003] At present, the silicon carbide single crystal growth is mainly by a physical vapor deposition method (PVT). After the silicon carbide powder is put into a crucible, the silicon carbide powder is directly sublimated into a gas at a temperature above 2100°C in a low-pressure environment, and is transported from a high-temperature zone to a seed crystal at a lower temperature zone for deposition and crystallization.

[0004] However, at present, only a single seed crystal can be placed in the crucible due to the influence of the thermal field, which makes only one silicon carbide single crystal be grown in one growth cycle, and the production capacity is low. SUMMARY

[0005] The purpose of the present application is to provide a crystal growth device, which improves the production capacity.

[0006] The present application provides a crystal growth device, which comprises a crucible body, the crucible body comprises a crucible bottom wall and a crucible side wall connected with each other, and the crucible bottom wall and the crucible side wall form a cavity.

[0007] A crucible cover is arranged on the side of the crucible side wall opposite to the crucible bottom wall, and the side of the crucible cover facing the crucible bottom wall is used for arranging a first seed crystal.

[0008] A partition is arranged in the cavity, the side of the partition facing the crucible bottom wall is used for arranging a second seed crystal, and the side of the partition facing the crucible cover is used for carrying a first silicon carbide powder; and the crucible bottom wall is used for carrying a second silicon carbide powder.

[0009] A heating element is arranged on the outer periphery of the crucible side wall, which is used for sublimating the first silicon carbide powder and the second silicon carbide powder, and moving the sublimated growth atmosphere to the first seed crystal and the second seed crystal for crystallization.

[0010] The beneficial effects of the embodiments of the present application include:

[0011] By setting the partition in the chamber of the crucible body, and then heating the crucible body by the heating member, the second silicon carbide powder carried on the bottom wall of the crucible body and the first silicon carbide powder carried on the partition can be sublimated, and the sublimated growth atmosphere can be crystallized on the first seed crystal and the second seed crystal respectively by the temperature gradient formed in the crucible body by the heating member, so that at least two silicon carbide crystals can be obtained in one growth cycle, and the production capacity is improved. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0013] Figure 1 It is a schematic diagram of the crystal growth device of the embodiment of the present application.

[0014] The figure shows: 10-crucible body; 11-crucible side wall; 12-crucible bottom wall; 13-first growth chamber; 14-second growth chamber; 15-first silicon carbide powder; 16-second silicon carbide powder; 20-crucible cover; 30-first seed crystal; 40-partition; 41-intermediate part; 42-peripheral part; 50-second seed crystal; 60-flow guide cylinder; 70-raw material cylinder; 80-heating member; 81-first heating member; 82-second heating member. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art without creative labor based on the embodiments in the present application are within the scope of protection of the present application.

[0017] It should be noted that: similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0018] In the description of the present application, it needs to be explained that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0019] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0020] In the description of the present application, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0021] The following will be described in conjunction with the accompanying drawings Figure 1 Some embodiments of the present application will be described in detail. The following examples and features in the examples can be combined with each other without conflict.

[0022] The embodiment of the present application provides a crystal growth device, which comprises a crucible body 10, a crucible cover 20, a partition 40, a heating element 80, a vacuum device and a protective gas input device.

[0023] The crucible body 10 and the crucible cover 20 arranged on the top of the crucible body 10 are the main structure of the whole crystal growth device, to provide the environment and place for the growth of silicon carbide crystals. The heating element 80 is mainly used for heating the crucible body 10 to ensure that the inside can reach the temperature required for the growth of silicon carbide crystals. The vacuum device is mainly used for vacuumizing the inside of the crucible body 10, so as to facilitate the growth of silicon carbide crystals. The protective gas input device is mainly used for inputting inert gas such as argon into the crucible body 10, to serve as protective gas to ensure the efficient performance of the preparation of silicon carbide.

[0024] The crucible body 10 and the crucible cover 20 are made of high-purity high-density graphite material, and are hollow cylindrical in shape. The crucible body 10 includes a crucible bottom wall 12 and a crucible side wall 11 connected together. The crucible body 10 and the crucible side wall 11 together define a chamber. The top of the chamber is open, so that silicon carbide powder can be put into the chamber through the top opening of the crucible body 10. The silicon carbide powder is the raw material for preparing silicon carbide crystals, so as to ensure the growth of silicon carbide crystals. After the silicon carbide powder is put into the crucible body 10, the silicon carbide powder will deposit on the crucible bottom wall 12 under the action of gravity, and thus the crucible bottom wall 12 will carry the silicon carbide powder. Of course, the shape of the crucible body 10 can also be adjusted according to requirements, for example, it can be a square column.

[0025] The crucible cover 20 is arranged on the side of the crucible side wall 11 opposite the crucible bottom wall 12, and the side of the crucible cover 20 facing the crucible bottom wall 12 is used to arrange a first seed crystal 30. The first seed crystal 30 can be arranged at the center of the crucible cover 20, and it serves as a seed for growing silicon carbide crystals, and can provide an existing crystallization center. The first seed crystal 30 is usually in the form of a thin sheet.

[0026] A partition 40 is arranged in the chamber, and the side of the partition 40 facing the crucible bottom wall 12 is used to arrange a second seed crystal 50, which serves as a seed for growing silicon carbide crystals. The side of the partition 40 facing the crucible cover 20 can be used to carry silicon carbide powder.

[0027] A heating element 80 is arranged around the outer periphery of the crucible side wall 11, and is used to provide heat to sublimate the first silicon carbide powder 15 carried on the partition 40 and the second silicon carbide powder 16 carried on the crucible bottom wall 12, and to move the sublimated growth atmosphere to the first seed crystal 30 and the second seed crystal 50 for crystallization.

[0028] In this way, by arranging the partition 40 in the crucible and using the heating element 80 to heat the crucible body 10, the second silicon carbide powder 16 carried on the crucible bottom wall 12 and the first silicon carbide powder 15 carried on the partition 40 can be sublimated, and the sublimated growth atmosphere can be crystallized on the first seed crystal 30 and the second seed crystal 50 respectively by the temperature gradient formed in the crucible body 10 by the heating element 80, so that at least two silicon carbide crystals can be obtained in one growth cycle, thereby improving the production capacity.

[0029] In the embodiment, the number of the partition 40 is one, so as to divide the cavity of the crucible body 10 into the first growth cavity 13 and the second growth cavity 14, the first growth cavity 13 is enclosed by the crucible side wall 11 and the partition 40, the second growth cavity 14 is enclosed by the partition 40, the crucible side wall 11 and the crucible bottom wall 12, the first seed crystal 30 is located in the first growth cavity 13, the second seed crystal 50 is located in the second growth cavity 14, the number of the heating element 80 is two, which is divided into the first heating element 81 and the second heating element 82, the first heating element 81 is arranged corresponding to the first growth cavity 13, and the second heating element 82 is arranged corresponding to the second growth cavity 14. Thus, the silicon carbide powder in the first growth cavity 13 and the second growth cavity 14 is heated and sublimated by the two heating elements 80 respectively, and a temperature gradient is formed to make the sublimated growth atmosphere move to the first seed crystal 30 or the second seed crystal 50 for crystallization, so that two silicon carbide crystals can be produced in one growth cycle.

[0030] The heating element 80 can be a magnetic induction coil arranged around the outer circumferential side of the crucible side wall 11, which heats the crucible body 10 by electromagnetic induction heating, has high heating efficiency and good heating effect, so that the first growth cavity 13 and the second growth cavity 14 are provided with suitable temperature gradient by the up and down arrangement of the double magnetic induction coils.

[0031] Of course, in some embodiments, the number of the partition 40 can also be more than two, and the number of the corresponding heating element 80 is one more than the number of the partition 40. Since the second seed crystal 50 is arranged on the side of each partition 40 facing the crucible bottom wall 12, and the silicon carbide powder is carried on the side of each partition 40 facing the crucible cover 20, so that more than three silicon carbide crystals can be produced in each growth cycle. Each heating element 80 can also be a plurality of heating rods arranged in a circumferential interval outside the crucible body 10.

[0032] The partition 40 includes an intermediate part 41 and a peripheral part 42 connected to the outer periphery of the intermediate part 41, the peripheral part 42 is connected to the crucible side wall 11, and the intermediate part 41 is a hollow structure, and the side of the intermediate part 41 facing the crucible bottom wall 12 is used for arranging the second seed crystal 50. The peripheral part 42 is connected to the crucible side wall 11, so as to realize the fixation of the whole partition 40 in the crucible body 10. Since the temperature on the partition 40 is generally transmitted by heat, the intermediate part 41 is arranged as a hollow structure, so that the temperature of the intermediate part 41 is lower than that of the peripheral part 42, so that the partition 40 forms a radial temperature gradient, and the growth interface of the second seed crystal 50 arranged on the intermediate part 41 can form a radial temperature gradient, so as to ensure that the growth of the silicon carbide crystal in the second growth cavity 14 can be carried out normally.

[0033] The peripheral portion 42 can be directly abutted on a ring-shaped supporting step surface provided on the sidewall 11 of the crucible, so that the partition 40 is arranged in the chamber, and the partition 40 is facilitated to be taken out to place the silicon carbide powder on the bottom wall 12 of the crucible or to take out the residue after the growth is finished.

[0034] The peripheral portion 42 and the intermediate portion 41 can be detachably connected, so that the intermediate portion 41 is taken out alone to place the second seed crystal 50. Of course, in some embodiments, the peripheral portion 42 and the intermediate portion 41 can also be an integral structure.

[0035] In the embodiment, the peripheral portion 42 is configured to pass the growth atmosphere after the second silicon carbide sealing material is sublimated, and intercept the carbon particles carried by the growth atmosphere after the second silicon carbide powder 16 is sublimated, so that the excess growth atmosphere in the second growth chamber 14 can pass through the peripheral portion 42 to the first growth chamber 13 to crystallize at the first seed crystal 30, thereby improving the utilization rate of the raw material, and the carbon particles carried in the growth atmosphere can be intercepted through the peripheral portion 42 to improve the quality of the silicon carbide crystal grown at the first seed crystal 30. The peripheral portion 42 is graphite material with a porous structure to have the functions of atmosphere flow and intercepting carbon particles carried in the atmosphere. The thickness of the peripheral portion 42 can be 10-20 mm, and the porosity of the peripheral portion 42 can be 40-50%.

[0036] Since the crucible body 10 and the crucible cover 20 are both made of graphite material, during the growth of the silicon carbide crystal, the direct contact between the growth atmosphere and the crucible body 10 and the crucible cover 20 will cause the crucible body 10 and the crucible cover 20 to be corroded to form carbon particles, which are mixed into the silicon carbide crystal under the carrying of the growth atmosphere, resulting in poor growth quality of the silicon carbide crystal.

[0037] In order to improve the above-mentioned defects, the crystal growth device further comprises a flow guide cylinder 60 in the embodiment, one end of the flow guide cylinder 60 abuts against the crucible cover 20 to be able to cooperate with the outer periphery of the first seed crystal 30, and the other end of the flow guide cylinder 60 abuts against the partition 40.

[0038] Through the arrangement of the flow guide cylinder 60, the growth atmosphere can be shielded during the growth of the silicon carbide crystal, preventing the direct contact between the growth atmosphere and the crucible body 10 and the crucible cover 20, thereby preventing impurities from being mixed into the silicon carbide crystal to ensure the growth quality of the silicon carbide single crystal, and preventing the corrosion of the growth atmosphere to the crucible body 10 and the crucible cover 20 to prolong the service life of the crucible body 10 and the crucible cover 20.

[0039] The flow guide cylinder 60 can be made of a metal carbide material, such as dense high-temperature-resistant materials such as tantalum carbide and niobium carbide, which have good heat preservation performance and dense performance to prevent the direct contact between the growth atmosphere and the crucible body 10 and the crucible cover 20.

[0040] The draft tube 60 is generally conical, and the inner diameter of the draft tube 60 gradually decreases along the direction from the crucible bottom wall 12 to the crucible cover 20 to be adapted to the outer diameter of the first seed crystal 30, so that one end of the draft tube 60 is matched with the outer periphery of the first seed crystal 30. In this way, the draft tube 60 can guide the gas growth atmosphere to gather at the first seed crystal 30 to increase the crystal crystallization rate and the diameter expansion capability.

[0041] The first growth chamber 13 also has a raw material tube 70 arranged therein, one end of the raw material tube 70 abuts against one end of the draft tube 60 close to the partition 40, and the other end of the raw material tube 70 abuts against the partition 40, that is, the draft tube 60 indirectly abuts against the partition 40 through the raw material tube 70, and the raw material tube 70 and the partition 40 are used together to carry the first silicon carbide powder 15. In this way, the silicon carbide powder is surrounded by the raw material tube 70 and the partition 40 to play a carrying role, and the arrangement of the raw material tube 70 can also facilitate the heat conduction between the crucible side wall 11 and the partition 40, so that the silicon carbide powder carried on the partition 40 can be quickly heated to improve the heat conduction efficiency and the growth speed.

[0042] In addition, the other end of the draft tube 60 also abuts against the crucible side wall 11, and the raw material tube 70 also abuts against the crucible side wall 11, so as to further improve the heat conduction effect and the growth speed. At the same time, only the draft tube 60 and the raw material tube 70 are abutted against the crucible body 10, which can also facilitate the removal and assembly of the draft tube 60 and the raw material tube 70.

[0043] It can be understood that in some embodiments, the raw material tube 70 can also not be arranged, and the draft tube 60 can directly abut against the partition 40, for example, the raw material tube 70 is arranged as a straight tube section and a conical tube section coaxially connected, one end of the straight tube section away from the conical tube section abuts against the partition 40, and one end of the conical tube section away from the straight tube section abuts against the crucible cover 20, the straight tube section and the partition 40 are used together to carry the first silicon carbide powder 15, and the inner diameter of the conical tube section gradually decreases along the direction from the crucible bottom wall 12 to the crucible cover 20 to be adapted to the outer diameter of the first seed crystal 30, so that one end of the conical tube section away from the straight tube section is matched with the outer periphery of the first seed crystal 30.

[0044] The assembly process, working principle and beneficial effects of the silicon carbide crystal growth equipment provided by the embodiments of the present application are described in detail as follows:

[0045] The crystal growth device is assembled as follows: firstly, the silicon carbide powder is loaded into the cavity of the crucible body 10 to form the second silicon carbide powder 16 on the bottom wall 12 of the crucible, then the peripheral portion 42 of the partition 40 is placed above the second silicon carbide powder 16, the second seed crystal 50 is arranged on the intermediate portion 41 of the partition 40, and the intermediate portion 41 is arranged in the peripheral portion 42. Then, the raw material cylinder 70 is loaded, and the silicon carbide powder is loaded into the raw material cylinder 70 to form the first silicon carbide powder 15 on the partition 40, and then the flow guide cylinder 60 and the crucible cover 20 with the first seed crystal 30 are loaded.

[0046] In the growth process, firstly, the pressure in the crucible body 10 is reduced to 5x10 -2 mbar by using the vacuumizing device, then argon is input into the crucible body 10 by using the protective gas input device, the pressure in the crucible body 10 is controlled to be 600-800 mbar, the crucible is heated by using the heating element 80 (such as water-cooled induction coil energization), and 200-800 sccm of inert gas is input, and the temperature is heated to 2000-2300 ℃. After maintaining the temperature for 1-5 h, the input of argon is stopped, the flow of argon filled into the crucible body 10 is adjusted to control the pressure to be 5-100 mbar, and the temperature continues to be heated to 2050-2250 ℃. At this time, the silicon carbide powder begins to sublimate to become a growth atmosphere, and since the temperature in the region where the first seed crystal 30 and the second seed crystal 50 are arranged in the crucible body 10 is low, the growth atmosphere will flow from the high-temperature region to the low-temperature region along the temperature gradient to deposit crystals on the growth surfaces of the first seed crystal 30 and the second seed crystal 50; wherein the growth atmosphere in the second growth cavity 14 can enter the first growth cavity 13 through the peripheral portion 42 of the partition 40, and then flow into the flow guide cylinder 60 to contact the first seed crystal 30. After a deposition crystal time of 5-10 days, the growth of silicon carbide crystals is completed on the first seed crystal 30 and the second seed crystal 50, so that two silicon carbide crystals are obtained in one growth cycle.

[0047] In summary, the crystal growth device of the embodiment of the present application can make the second silicon carbide powder 16 carried on the bottom wall 12 of the crucible and the first silicon carbide powder 15 carried on the partition 40 sublimate when the crucible body 10 is heated by using the heating element 80, and the sublimated growth atmosphere can be crystallized and grown on the first seed crystal 30 and the second seed crystal 50 respectively through the temperature gradient formed in the crucible body 10 by the heating element 80, so that at least two silicon carbide crystals can be obtained in one growth cycle, and the production capacity is improved.

[0048] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A crystal growth apparatus, characterized in that, include: A crucible body, the crucible body including a connected crucible bottom wall and a crucible side wall, the crucible bottom wall and the crucible side wall enclosing a cavity; A crucible lid is disposed on the side of the crucible sidewall opposite to the bottom wall of the crucible, and the side of the crucible lid facing the bottom wall of the crucible is used to set the first seed crystal. A separator is disposed within the cavity; the side of the separator facing the bottom wall of the crucible is used to hold the second seed crystal, and the side of the separator facing the crucible lid is used to hold the first silicon carbide powder; the bottom wall of the crucible is used to hold the second silicon carbide powder. A heating element is disposed on the outer periphery of the side wall of the crucible, used to sublimate the first silicon carbide powder and the second silicon carbide powder, and to move the sublimated growth atmosphere to the first seed crystal and the second seed crystal for crystallization; The separator includes a central portion and a peripheral portion connected to the outer periphery of the central portion. The peripheral portion is connected to the side wall of the crucible. The central portion is hollow, and the side of the central portion facing the bottom wall of the crucible is used to set the second seed crystal.

2. The crystal growth apparatus according to claim 1, characterized in that, The number of the partition is one, which divides the chamber into a first growth chamber and a second growth chamber. The crucible sidewall and the partition form the first growth chamber, and the partition, the crucible sidewall and the crucible bottom wall form the second growth chamber. The heating element includes a first heating element and a second heating element, wherein the first heating element is disposed corresponding to the first growth chamber and the second heating element is disposed corresponding to the second growth chamber.

3. The crystal growth apparatus according to claim 1, characterized in that, The heating element is a magnetic coil wound around the outer periphery of the side wall of the crucible.

4. The crystal growth apparatus according to claim 1, characterized in that, The periphery is configured to allow the growth atmosphere after the second silicon carbide powder sublimation to pass through, and to intercept carbon particles carried by the growth atmosphere after the second silicon carbide powder sublimation.

5. The crystal growth apparatus according to claim 4, characterized in that, The periphery is made of graphite material with a porous structure.

6. The crystal growth apparatus according to claim 5, characterized in that, The thickness of the periphery is 10~20mm; And / or, The porosity of the periphery is 40-50%.

7. The crystal growth apparatus according to claim 2, characterized in that, The first growth chamber is also provided with a flow guide tube, one end of which abuts against the crucible cover and the other end of which abuts against the separator.

8. The crystal growth apparatus according to claim 7, characterized in that, The guide tube is conical, and its inner diameter gradually decreases along the direction from the bottom wall of the crucible to the lid of the crucible until it can match the outer diameter of the first seed crystal.

9. The crystal growth apparatus according to claim 7, characterized in that, The first growth chamber is also provided with a raw material cylinder. One end of the raw material cylinder abuts against the end of the guide cylinder near the separator, and the other end of the raw material cylinder abuts against the separator. The raw material cylinder and the separator are used together to carry the first silicon carbide powder.

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