Silicon carbide growth device

Abstract

The utility model relates to a silicon carbide growing device which comprises a graphite crucible, a first heating assembly and a second heating assembly, the graphite crucible is used for accommodating a silicon solution; the first heating assembly is arranged on the bottom wall of the graphite crucible and is used for reducing the temperature gradient of the silicon solution in the radial direction of the graphite crucible; and the second heating assembly is arranged on the side wall of the graphite crucible and is used for reducing the temperature gradient of the silicon solution in the axial direction of the graphite crucible. The actual effects of the first heating assembly and the second heating assembly can be complementary, through mutual cooperation of the first heating assembly and the second heating assembly, the temperature uniformity of a silicon solution in the axial direction and the radial direction of the graphite crucible can be improved at the same time, the controllability and predictability of the temperature of the lower end of a seed rod are effectively improved, and the production efficiency is improved. The temperature of the lower end of the seed rod can be well maintained in an ideal growth temperature range of silicon carbide, so that the growth quality of the silicon carbide is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to silicon carbide growth field especially is related to a silicon carbide growth device. BACKGROUND

[0002] The growth process of silicon carbide is generally as follows: silicon material is put into a graphite crucible, a heating assembly heats the silicon material to form a silicon solution, and carbon elements contained in the graphite crucible enter the silicon solution, so that silicon carbide grows on the seed crystal at the lower end of the seed crystal rod.

[0003] The temperature uniformity of the silicon solution in the graphite crucible is poor, so the temperature at the lower end of the seed crystal rod is difficult to control. In addition, as the silicon carbide grows, the liquid level of the silicon solution gradually decreases, which causes the temperature distribution of the silicon solution to continuously change, resulting in an increase in the uncontrollability of the temperature at the lower end of the seed crystal rod. Based on the above reasons, the temperature at the lower end of the seed crystal rod is easily out of the ideal growth temperature range of silicon carbide, causing the problem of poor growth quality of silicon carbide. SUMMARY

[0004] Therefore, it is necessary to provide a silicon carbide growth device to solve the problem of poor growth quality of silicon carbide caused by the poor controllability of the temperature at the lower end of the seed crystal rod.

[0005] A silicon carbide growth device, comprising a graphite crucible, a first heating assembly and a second heating assembly.

[0006] The graphite crucible is used to contain a silicon solution.

[0007] The first heating assembly is arranged at the bottom wall of the graphite crucible, and the first heating assembly is used to reduce the temperature gradient of the silicon solution in the radial direction of the graphite crucible.

[0008] The second heating assembly is arranged at the side wall of the graphite crucible, and the second heating assembly is used to reduce the temperature gradient of the silicon solution in the axial direction of the graphite crucible.

[0009] The second heating assembly comprises a plurality of heating rings, and the heating rings are annularly arranged on the outer side wall of the graphite crucible.

[0010] The second heating assembly comprises a heating pipe, and the heating pipe extends spirally around the axis of the graphite crucible on the outer side wall of the graphite crucible.

[0011] The first heating assembly comprises a substrate, a first heater and at least two second heaters, the substrate is attached to the bottom outer wall of the graphite crucible, the first heater and the second heater are both mounted on the substrate, and the second heater is annularly arranged on the circumferential side of the first heater.

[0012] The silicon carbide growth device further comprises a seed crystal rod and an electronic thermometer, the lower end of the seed crystal rod and the electronic thermometer are located in the graphite crucible, and the interval between the lower end of the seed crystal rod and the inner wall of the bottom of the graphite crucible is equal to the interval between the electronic thermometer and the inner wall of the bottom of the graphite crucible.

[0013] The silicon carbide growth device further comprises a crucible cover, the crucible cover is covered on the top opening of the graphite crucible, the first avoiding hole and the second avoiding hole are formed in the crucible cover, the seed crystal rod is arranged in the first avoiding hole, and the electronic thermometer is hung in the graphite crucible through the second avoiding hole.

[0014] The silicon carbide growth device further comprises a controller, and the electronic thermometer, the first heating assembly and the second heating assembly are electrically connected to the controller.

[0015] The silicon carbide growth device further comprises a lifting unit, and the graphite crucible is supported on the top of the lifting unit, so that the lower end of the seed crystal rod and the electronic thermometer are located at the liquid level of the silicon solution.

[0016] The silicon carbide growth device further comprises a heat preservation layer, and the heat preservation layer is arranged around the side of the graphite crucible.

[0017] The heat preservation layer is fixed to the bottom of the lifting unit.

[0018] The silicon carbide growth device has the following beneficial effects:

[0019] The first heating assembly and the second heating assembly cooperate to heat the silicon material in the graphite crucible, so that the silicon material gradually changes into a silicon solution, and at the same time, the carbon element in the graphite crucible can continuously enter the silicon solution, thereby continuously generating silicon carbide.

[0020] The first heating assembly is arranged at the bottom wall of the graphite crucible, and the silicon solution is heated from bottom to top, which increases the temperature change of the silicon solution in the axial direction of the graphite crucible, but the first heating assembly can uniformly heat the entire bottom wall of the graphite crucible in this process, thereby reducing the temperature change of the silicon solution in the radial direction of the graphite crucible, so that the temperature uniformity of the silicon solution in the radial direction of the graphite crucible can be improved.

[0021] The second heating assembly is arranged at the sidewall of the graphite crucible, and the silicon solution is heated from outside to inside, which increases the temperature change of the silicon solution in the radial direction of the graphite crucible, but the second heating assembly can uniformly heat the whole sidewall of the graphite crucible, so that the temperature change of the silicon solution in the axial direction of the graphite crucible is reduced, and the temperature uniformity of the silicon solution in the axial direction of the graphite crucible is improved.

[0022] In summary, the actual effects of the first heating assembly and the second heating assembly can be complementary, and through the cooperation of the first heating assembly and the second heating assembly, the temperature uniformity of the silicon solution in the axial and radial directions of the graphite crucible is improved at the same time, the controllability and predictability of the temperature of the lower end of the seed rod are effectively improved, and the temperature of the lower end of the seed rod can be well maintained in the ideal growth temperature range of silicon carbide, so that the growth quality of silicon carbide is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a cross-sectional structure schematic view of the silicon carbide growth device in the embodiment of the utility model before the lifting unit is lifted.

[0024] Figure 2 It is a cross-sectional structure schematic view of the silicon carbide growth device in the embodiment of the utility model after the lifting unit is lifted.

[0025] Figure 3 It is a front view structure schematic view of the first heating assembly in the embodiment of the utility model.

[0026] REFERENCE NUMERALS:

[0027] 1, graphite crucible; 2, first heating assembly; 21, base plate; 22, first heater; 23, second heater; 3, second heating assembly; 4, seed rod; 41, seed crystal; 5, electronic thermometer; 6, crucible cover; 61, first avoiding hole; 62, second avoiding hole; 7, lifting unit; 8, heat preservation layer; 100, silicon solution. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the specific embodiments of the utility model are described in detail below. In the following description, a lot of specific details are set forth in order to fully understand the utility model. However, the utility model can be implemented in many other ways different from the description herein, and those skilled in the art can make similar improvements without departing from the connotation of the utility model, so the utility model is not limited by the following disclosed specific embodiments.

[0029] In the description of the utility model, it is understood that the orientation or positional relationship indicated by 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 is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0030] In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0031] In the utility model, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; 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 or interaction relationship between two elements, unless otherwise specifically limited. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0032] In the utility model, unless otherwise specifically defined and limited, the first feature "on" or "under" the second feature can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0033] It is to be noted that when an element is referred to as being "on" or "connected to" another element, it can be directly on the other element or intervening elements can be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present. As used herein the terms "vertical", "horizontal", "up", "down", "left", "right", and the like are used for clarity to provide relative description only. They are not meant to limit the position of the apparatus to only these orientations.

[0034] Embodiment:

[0035] Referring to Figure 1 The embodiment provides a silicon carbide growth device, which comprises a graphite crucible 1, a first heating assembly 2, a second heating assembly 3 and a seed rod 4.

[0036] The graphite crucible 1 is generally cylindrical, the top of the graphite crucible 1 is open to allow silicon material to be put into the graphite crucible 1, the first heating assembly 2 and the second heating assembly 3 can heat the graphite crucible 1, the graphite crucible 1 conducts heat to the silicon material, so that the silicon material is continuously converted into a silicon solution 100, and at the same time, carbon elements in the graphite crucible 1 can also be continuously dissolved into the silicon solution 100.

[0037] The seed rod 4 is arranged vertically to the horizontal plane, so the extending direction of the seed rod 4 is vertical. A seed crystal 41 is arranged at the lower end of the seed rod 4, and the upper end of the seed rod 4 is hoisted, so that the seed crystal 41 is immersed in the silicon solution 100 and arranged in a spaced manner with the bottom wall of the graphite crucible 1. At a suitable temperature, silicon carbide will continuously grow on the seed crystal 41.

[0038] In the embodiment, the first heating assembly 2 is arranged at the bottom wall of the graphite crucible 1, more specifically, the first heating assembly 2 is located at the outer bottom wall of the graphite crucible 1. The first heating assembly 2 is in surface contact with the entire bottom wall of the graphite crucible 1 as much as possible, so that the first heating assembly 2 can uniformly heat the entire bottom wall of the graphite crucible 1, and therefore, based on the heating process of the first heating assembly 2, the temperature change of the silicon solution 100 in the radial direction of the graphite crucible 1 is significantly reduced, so that the heating of the first heating assembly 2 at the bottom wall of the graphite crucible 1 can significantly improve the temperature uniformity of the silicon solution 100 in the radial direction of the graphite crucible 1 and the circumferential direction of the graphite crucible 1.

[0039] Referring to Figure 3The first heating assembly 2 in the embodiment includes a base plate 21, a first heater 22, and at least two second heaters 23. The base plate 21 is a circular plate, and the diameter of the base plate 21 is consistent with the outer diameter of the graphite crucible 1, so that the base plate 21 is attached to the outer wall of the bottom of the graphite crucible 1. The first heater 22 and the second heater 23 are both mounted on the base plate 21, and the first heater 22 is located at the center of the base plate 21, so that the first heater 22 is also located at the center of the bottom wall of the graphite crucible 1. The second heaters 23 are arranged in turn and equidistantly around the circumferential side of the first heater 22, so as to ensure the uniformity of heating of the entire bottom wall of the graphite crucible 1.

[0040] It is worth noting that the heat generated by the first heating assembly 2 in the embodiment is conducted along the axial direction of the graphite crucible 1 from bottom to top, so that the temperature of the silicon solution 100 in the axial direction of the graphite crucible 1 changes.

[0041] The second heating assembly 3 in the embodiment is arranged at the side wall of the graphite crucible 1, and more specifically, the second heating assembly 3 is arranged at the outer side wall of the graphite crucible 1. The second heating assembly 3 is similar to a heating pipe sleeve for the graphite crucible 1, so as to coat the outer wall of the graphite crucible 1. The second heating assembly 3 can coat the entire outer wall of the graphite crucible 1, or can coat part of the outer wall of the graphite crucible 1, but at least needs to ensure that the silicon solution 100 is located in the middle of the second heating assembly 3, so as to ensure that the second heating assembly 3 can effectively conduct heat to the silicon solution 100 through the side wall of the graphite crucible 1.

[0042] In some embodiments, the second heating assembly 3 includes a plurality of heating rings, and the heating rings are annular and arranged in turn and equidistantly around the outer side wall of the graphite crucible 1.

[0043] In another part of the embodiments, the second heating assembly 3 includes a heating pipe, and the heating pipe extends in a spiral shape, and the spiral axis of the heating pipe coincides with the axis of the graphite crucible 1. The heating pipe is relatively densely wound on the outer side wall of the graphite crucible 1.

[0044] The part of the outer wall of the graphite crucible 1 coated by the second heating assembly 3 can obtain relatively uniform heating, wherein the coating direction of the second heating assembly 3 to the outer wall of the graphite crucible 1 includes the circumferential direction of the graphite crucible 1 and the axial direction of the graphite crucible 1. Therefore, the temperature uniformity of the silicon solution 100 in the circumferential direction of the graphite crucible 1 is good, and the temperature uniformity of the silicon solution 100 in the axial direction of the graphite crucible 1 is also good.

[0045] On the other hand, the heat generated by the second heating assembly 3 is conducted to the silicon solution 100 in the direction from the radial outer side of the graphite crucible 1 to the radial inner side of the graphite crucible 1, so that the temperature of the silicon solution 100 in the radial direction of the graphite crucible 1 changes.

[0046] It can be seen that the first heating assembly 2 and the second heating assembly 3 are complementary in function. Specifically, the first heating assembly 2 can improve the temperature uniformity of the silicon solution 100 in the radial direction of the graphite crucible 1, so as to reduce the adverse effect of the second heating assembly 3 on the temperature uniformity of the silicon solution 100 in the radial direction of the graphite crucible 1. Similarly, the second heating assembly 3 can improve the temperature uniformity of the silicon solution 100 in the axial direction of the graphite crucible 1, so as to reduce the adverse effect of the first heating assembly 2 on the temperature uniformity of the silicon solution 100 in the axial direction of the graphite crucible 1.

[0047] In this embodiment, the temperature difference between different positions of the silicon solution 100 is significantly reduced by the cooperation of the first heating assembly 2 and the second heating assembly 3, and the temperature uniformity of the silicon solution 100 is significantly improved, which makes the temperature at the position of the seed crystal 41 more controllable and predictable, and more easily adapts the temperature at the position of the seed crystal 41 to the growth temperature of silicon carbide.

[0048] The silicon carbide growth device in this embodiment further comprises an electronic thermometer 5, which is located in the graphite crucible 1 and is also immersed in the silicon solution 100 to allow the electronic thermometer 5 to detect the temperature of the silicon solution 100. In order to prevent the electronic thermometer 5 from interfering with the growth process of silicon carbide, the electronic thermometer 5 is usually arranged in a spaced-apart state with the seed crystal 41.

[0049] It is particularly worth noting that, due to the significant improvement in the temperature uniformity of the silicon solution 100 in this embodiment, even if there is a certain spacing between the electronic thermometer 5 and the seed crystal 41, the detection value of the electronic thermometer 5 can still accurately reflect the temperature at the position of the seed crystal 41, so that the heating power of the first heating assembly 2 and / or the second heating assembly 3 can be adjusted according to the detection value of the electronic thermometer 5, so that the temperature at the position of the seed crystal 41 can be continuously maintained within the ideal growth temperature range of silicon carbide.

[0050] Specifically, the silicon carbide growth device further comprises a controller, and the electronic thermometer 5, the first heating assembly 2 and the second heating assembly 3 are electrically connected to the controller, and the controller controls the first heating assembly 2 and the second heating assembly 3 based on the feedback signal of the electronic thermometer 5.

[0051] Of course, in order to further close the temperature at the position of the seed crystal 41 and the temperature at the position of the electronic thermometer 5, the spacing between the seed crystal 41 (the lower end of the seed crystal rod 4) and the inner wall of the bottom of the graphite crucible 1 is equal to the spacing between the electronic thermometer 5 and the inner wall of the bottom of the graphite crucible 1.

[0052] The silicon carbide growth device further comprises a crucible cover 6 which covers the top opening of the graphite crucible 1, and the crucible cover 6 has a heat preservation effect and reduces heat loss of the silicon solution 100. In order to allow the lower end of the seed rod 4 and the electronic temperature gauge 5 to enter the graphite crucible 1, the crucible cover 6 is provided with a first avoiding hole 61 and a second avoiding hole 62, the seed rod 4 is arranged at the first avoiding hole 61, and the crucible cover 6 avoids the seed rod 4 through the first avoiding hole 61. The electronic temperature gauge 5 is hung in the graphite crucible 1 through the second avoiding hole 62.

[0053] Referring to Figure 1 and Figure 2 , the silicon carbide growth device further comprises a lifting unit 7, the bottom of the lifting unit 7 is fixed, and the top of the lifting unit 7 can be lifted relative to the bottom. The graphite crucible 1 is supported on the top of the lifting unit 7, and correspondingly, the first heating assembly 2 is located between the lifting unit 7 and the bottom wall of the graphite crucible 1. The lifting unit 7 can drive the graphite crucible 1 to be lifted, and the electronic temperature gauge 5 and the seed crystal 41 remain stationary during the lifting of the graphite crucible 1.

[0054] With the continuous growth of the silicon carbide, the liquid level of the silicon solution 100 continuously decreases, and the lifting unit 7 lifts the graphite crucible 1, so that the electronic temperature gauge 5 and the seed crystal 41 (the lower end of the seed rod 4) are always immersed in the silicon solution 100, for example, always at the liquid level of the silicon solution 100.

[0055] Preferably, the silicon carbide growth device further comprises a heat preservation layer 8 which is arranged around the graphite crucible 1, and the second heating assembly 3 is located between the heat preservation layer 8 and the outer sidewall of the graphite crucible 1. The heat preservation layer 8 can make the heat generated by the second heating assembly 3 be conducted to the silicon solution 100 as much as possible.

[0056] In the embodiment, the heat preservation layer 8 is fixed to the bottom of the lifting unit 7, so that the heat preservation layer 8 does not move with the graphite crucible 1 during the lifting of the graphite crucible 1.

[0057] The technical features of the above-described embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the description.

[0058] The above-described embodiments only express several implementation manners of the utility model, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the utility model patent. It should be pointed out that for ordinary skilled persons in the art, on the premise of not departing from the concept of the utility model, a number of modifications and improvements can be made, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A silicon carbide growth apparatus, comprising: The graphite crucible (1), the first heating assembly (2) and the second heating assembly (3); The graphite crucible (1) is used for containing a silicon solution (100); The first heating assembly (2) is arranged at a bottom wall of the graphite crucible (1), and is used for reducing a temperature gradient of the silicon solution (100) in a radial direction of the graphite crucible (1); The second heating assembly (3) is arranged at a side wall of the graphite crucible (1), and is used for reducing a temperature gradient of the silicon solution (100) in an axial direction of the graphite crucible (1).

2. The silicon carbide growth apparatus of claim 1, wherein, The second heating assembly (3) comprises a plurality of heating rings, which are annularly arranged on an outer side wall of the graphite crucible (1).

3. The silicon carbide growth apparatus of claim 1, wherein, The second heating assembly (3) comprises a heating pipe, which extends spirally on an outer side wall of the graphite crucible (1) around an axis of the graphite crucible (1).

4. The silicon carbide growth apparatus of claim 1, wherein, The first heating assembly (2) comprises a base plate (21), a first heater (22) and at least two second heaters (23), the base plate (21) is attached to an outer bottom wall of the graphite crucible (1), the first heater (22) and the second heaters (23) are both mounted on the base plate (21), and the second heaters (23) are annularly arranged on a periphery of the first heater (22).

5. The silicon carbide growth apparatus of claim 1, wherein, The silicon carbide growth device further comprises a seed rod (4) and an electronic thermometer (5), the lower end of the seed rod (4) and the electronic thermometer (5) are both located in the graphite crucible (1), and the distance between the lower end of the seed rod (4) and the inner bottom wall of the graphite crucible (1) is equal to the distance between the electronic thermometer (5) and the inner bottom wall of the graphite crucible (1).

6. The silicon carbide growth apparatus of claim 5, wherein, The silicon carbide growth device further comprises a crucible cover (6), the crucible cover (6) covers a top opening of the graphite crucible (1), the crucible cover (6) is provided with a first avoiding hole (61) and a second avoiding hole (62), the seed rod (4) passes through the first avoiding hole (61), and the electronic thermometer (5) is hung in the graphite crucible (1) through the second avoiding hole (62).

7. The silicon carbide growth apparatus of claim 5, wherein, The silicon carbide growth device further comprises a controller, and the electronic thermometer (5), the first heating assembly (2) and the second heating assembly (3) are all electrically connected to the controller.

8. The silicon carbide growth apparatus of claim 5, wherein, The silicon carbide growth device further comprises a lifting unit (7), and the graphite crucible (1) is supported on the top of the lifting unit (7) to allow the lower end of the seed rod (4) and the electronic thermometer (5) to be located at the liquid level of the silicon solution (100).

9. The silicon carbide growth apparatus of claim 8, wherein, The silicon carbide growth device further comprises a heat preservation layer (8), which is annularly arranged on the periphery of the graphite crucible (1).

10. The silicon carbide growth apparatus of claim 9, wherein, The heat preservation layer (8) is fixed to the bottom of the lifting unit (7).

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