A graphite crucible for silicon carbide crystal growth

Abstract

The utility model relates to a graphite crucible for silicon carbide crystal growth, including base member, first annular member and second annular member, base member includes base part, first annular wall part and second annular wall part, and first annular wall part stands up from the circumference of base part, and second annular wall part is inside first annular wall part, and is coaxial with first annular wall part and is arranged, first annular member is detachably connected with the one end of first annular wall part away from base part, and constitutes the outside wall of the side wall of graphite crucible for silicon carbide crystal growth, second annular member is detachably connected with the one end of second annular wall part away from base part, and constitutes the inside wall of the side wall, and the cavity between outside wall and inside wall has. The above-mentioned graphite crucible can replace only the component with serious corrosion condition, reduce the cost of silicon carbide crystal growth, and the double-layer cavity structure can play the effect of reinforcing the heat preservation, according to the actual demand control the size of cavity, the heat preservation effect of graphite crucible can be adjusted.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, and in particular to a graphite crucible for silicon carbide crystal growth. Background Technology

[0002] Silicon carbide has significant advantages in fields such as radio frequency devices and power devices. The bottleneck in the market application of its substrate is its high production cost (accounting for more than 50% of the total device cost), among which equipment, energy, raw materials and yield are the core driving factors.

[0003] In the raw materials for silicon carbide substrate preparation, graphite components account for 30% to 50% of the cost. Crucibles (graphite components) refer to vessels made by pressing graphite powder of a certain particle size under high pressure and then calcining it at high temperature for a long time. They have the characteristics of high temperature resistance, strong thermal conductivity, good corrosion resistance, and long life. They are one of the consumables in the silicon carbide crystal growth process. During the preparation of silicon carbide, carbon in the crucible will be dispersed and fall off with the gas flow. Therefore, the contact area between the crucible and the silicon carbide raw material is severely corroded. After a period of use, the entire crucible needs to be replaced. This is a major reason for the high cost of graphite components in the silicon carbide preparation process. Utility Model Content

[0004] The purpose of this invention is to provide a graphite crucible for silicon carbide crystal growth, so as to reduce the cost of silicon carbide crystal growth.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A first aspect of this application provides a graphite crucible for silicon carbide crystal growth, comprising:

[0007] A base component, the base component including a base bottom, a first annular wall portion and a second annular wall portion, the first annular wall portion rising from the periphery of the base portion, the second annular wall portion being inside the first annular wall portion and coaxially disposed on the base bottom with the first annular wall portion;

[0008] The first annular member is detachably connected to the end of the first annular wall portion away from the base, forming the outer wall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth.

[0009] The second annular member is detachably connected to the end of the second annular wall away from the base, forming the inner sidewall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth, and there is a cavity between the outer sidewall and the inner sidewall.

[0010] In one possible implementation, the first annular member is threaded or snap-fitted to the first annular wall portion, and the second annular member is threaded or snap-fitted to the second annular wall portion.

[0011] In one possible implementation, one of the first annular member and the first annular wall portion is provided with a first protrusion, and the other of the first annular member and the first annular wall portion is provided with a first recess, the first protrusion and the first recess engaging in a convex-concave engagement; and / or, one of the second annular member and the second annular wall portion is provided with a second protrusion, and the other of the second annular member and the second annular wall portion is provided with a second recess, the second protrusion and the second recess engaging in a convex-concave engagement.

[0012] In one possible implementation, the first protrusion is a columnar annular boss, and the first recess is a columnar annular groove, wherein the columnar annular boss and the columnar annular groove are inserted into each other.

[0013] In one possible implementation, the vertical plane passing through the axis of the graphite crucible for silicon carbide crystal growth is the longitudinal symmetry plane of the graphite crucible for silicon carbide crystal growth, and the cross-sectional shape formed by the intersection of the second convex part and the second concave part with the longitudinal symmetry plane is a triangle or a trapezoid.

[0014] In one possible implementation, the inner circumferential surface of the first annular member is flush with the inner circumferential surface of the first annular wall portion, the outer circumferential surface of the first annular member is flush with the outer circumferential surface of the first annular wall portion, the inner circumferential surface of the second annular member is flush with the inner circumferential surface of the second annular wall portion, and the outer circumferential surface of the second annular member is flush with the outer circumferential surface of the second annular wall portion.

[0015] In one possible implementation, the thickness of the outer sidewall is greater than or equal to the thickness of the inner sidewall.

[0016] In one possible implementation, the thickness of the outer sidewall is 4 mm to 8 mm greater than the thickness of the inner sidewall.

[0017] In one possible implementation, the thickness of the crucible sidewall is 25 mm to 40 mm, and the dimension of the cavity along the thickness direction of the crucible sidewall is 3 mm to 6 mm.

[0018] In one possible implementation, the first annular member is formed by splicing together a plurality of first ring bodies along the axial and / or radial direction of the graphite crucible for silicon carbide crystal growth, and / or the second annular member is formed by splicing together a plurality of second ring bodies along the axial and / or radial direction of the graphite crucible for silicon carbide crystal growth.

[0019] As can be seen from the above technical solution, the graphite crucible for silicon carbide crystal growth provided by this utility model includes a substrate component, a first annular component, and a second annular component. The substrate component includes a base bottom, a first annular wall portion, and a second annular wall portion. The first annular wall portion rises from the periphery of the base portion, and the second annular wall portion is disposed coaxially with the first annular wall portion on the base bottom inside the first annular wall portion. The end of the first annular component away from the base bottom is detachably connected to the first annular wall portion, forming the outer wall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth. The end of the second annular component away from the base bottom is detachably connected to the second annular wall portion, forming the inner wall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth. A cavity exists between the outer wall and the inner wall.

[0020] In application, the position and size of the second annular component can be defined according to the height of the crucible where corrosion is most severe during silicon carbide single crystal preparation. This allows the base component, the first annular component, and the second annular component to be replaced separately based on the corrosion situation. This means that only the severely corroded components need to be replaced, while those with less severe corrosion can continue to be used, avoiding frequent replacement of the entire graphite crucible, reducing the cost of silicon carbide crystal growth. Furthermore, the double-layer cavity structure can enhance the heat preservation effect. When preparing graphite crucibles for silicon carbide crystal growth, the size of the cavity can be controlled according to actual needs, thereby adjusting the heat preservation effect of the graphite crucible for silicon carbide crystal growth. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A cross-sectional view of a graphite crucible for silicon carbide crystal growth provided in an embodiment of this utility model;

[0023] Figure 2 A cross-sectional view of the substrate component of a graphite crucible for silicon carbide crystal growth provided in an embodiment of this utility model;

[0024] Figure 3 A cross-sectional view of the first annular component of the graphite crucible for silicon carbide crystal growth provided in an embodiment of this utility model;

[0025] Figure 4 A cross-sectional view of the second annular component of the graphite crucible for silicon carbide crystal growth provided in an embodiment of this utility model.

[0026] In the picture:

[0027] 100 is the base component; 110 is the base bottom; 120 is the first annular wall portion; 130 is the second annular wall portion; 121 is the first concave portion; 131 is the second convex portion;

[0028] 200 is the first annular component; 210 is the first protrusion;

[0029] 300 is the second annular component; 310 is the second recess. Detailed Implementation

[0030] The core of this invention is to provide a graphite crucible for silicon carbide crystal growth, the structural design of which enables the reduction of silicon carbide crystal growth costs.

[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0032] This embodiment of the invention discloses a graphite crucible for silicon carbide crystal growth. Please refer to [link / reference]. Figures 1 to 4 The graphite crucible for silicon carbide crystal growth includes a substrate component 100, a first annular component 200, and a second annular component 300.

[0033] Among them, the base component 100, the first annular component 200, and the second annular component 300 are all made of graphite, such as Figure 1 As shown, the substrate component 100 includes a base 110, a first annular wall portion 120 and a second annular wall portion 130. The base 110 serves as the crucible bottom of a graphite crucible for silicon carbide crystal growth, and it is an integral structure with the first annular wall portion 120 and the second annular wall portion 130.

[0034] Please continue reading. Figure 1The first annular wall portion 120 rises from the periphery of the base 110, and is perpendicular or substantially perpendicular to the base 110. The second annular wall portion 130 is disposed coaxially with the first annular wall portion 120 on the base 110, inside the first annular wall portion 120. The axial dimensions of the first annular wall portion 120 and the second annular wall portion 130, i.e., their heights, can be set according to the corrosion condition of the graphite crucible used for silicon carbide crystal growth. In order to enable the substrate component 100 to be reused multiple times, the first annular wall portion 120... The top of the first annular wall portion 120 and the second annular wall portion 130 should preferably not exceed the lower boundary of the area where the graphite crucible for silicon carbide crystal growth is most severely corroded. The heights of the first annular wall portion 120 and the second annular wall portion 130 can be the same or different. For example, the first annular wall portion 120 can be taller than the second annular wall portion 130, which is a structure with a higher outer side and a lower inner side. Alternatively, the first annular wall portion 120 can be shorter than the second annular wall portion 130, which is a structure with a lower outer side and a higher inner side. Or, they can be made to be the same height.

[0035] The dimensions perpendicular to the axial direction of the first annular wall portion 120 and the second annular wall portion 130, i.e., their thicknesses, need to ensure the strength of the crucible sidewall of the graphite crucible for silicon carbide crystal growth, and the thicknesses of the two portions can be the same or different.

[0036] There is a gap between the first annular wall portion 120 and the second annular wall portion 130, that is, the sum of the thicknesses of the first annular wall portion 120 and the second annular wall portion 130 is less than the overall thickness of the crucible sidewall of the graphite crucible for silicon carbide crystal growth described below.

[0037] Please see Figure 1 and Figure 3 The first annular member 200 is detachably connected to the end of the first annular wall portion 120 away from the base 110, forming the outer wall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth.

[0038] Please see Figure 1 and Figure 4 The second annular member 300 is detachably connected to the end of the second annular wall portion 130 away from the base 110, forming the inner sidewall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth. There is a cavity between the outer sidewall and the inner sidewall, that is, the crucible sidewall of the graphite crucible for silicon carbide crystal growth adopts a double-layer cavity structure. Since the first annular member 200 and the second annular member 300 are detachably connected to the base member 100, the base member 100, the first annular member 200 and the second annular member 300 can be replaced according to the corrosion condition during the production process. That is, only the severely corroded parts are replaced, and the less severely corroded parts are reused, avoiding the cost increase caused by the need to replace the whole integrated structure.

[0039] In the application of the graphite crucible for silicon carbide crystal growth provided in this embodiment, the position and size of the second annular component 300 can be defined according to the height of the crucible where corrosion is most severe during the preparation of silicon carbide single crystals. This allows the substrate component 100, the first annular component 200, and the second annular component 300 to be replaced separately according to the corrosion situation. This means that only the severely corroded components need to be replaced, while those with less severe corrosion can continue to be used, avoiding frequent replacement of the entire graphite crucible, reducing the cost of silicon carbide crystal growth. Furthermore, the double-layer cavity structure can enhance the heat preservation effect. When preparing the graphite crucible for silicon carbide crystal growth, the size of the cavity can be controlled according to actual needs, thereby adjusting the heat preservation effect of the graphite crucible for silicon carbide crystal growth.

[0040] The first annular member 200 and the first annular wall portion 120, as well as the second annular member 300 and the second annular wall portion 130, can be connected in various ways. In this application, the first annular member 200 and the first annular wall portion 120 are connected by threads or by snap-fit, and the second annular member 300 and the second annular wall portion 130 are connected by threads or by snap-fit. Snap-fit ​​connection is more convenient to assemble, while threaded connection has better strength and sealing performance. The connection method between the first annular member 200 and the first annular wall portion 120, as well as between the second annular member 300 and the second annular wall portion 130, can be adaptively designed according to the shape of the silicon carbide raw material and the load-bearing requirements.

[0041] To facilitate assembly and disassembly, one of the first annular member 200 and the first annular wall portion 120 is provided with a first protrusion 210, and the other of the first annular member 200 and the first annular wall portion 120 is provided with a first recess 121. The first protrusion 210 and the first recess 121 are engaged in a convex-concave engagement. Alternatively, one of the second annular member 300 and the second annular wall portion 130 is provided with a second protrusion 131, and the other of the second annular member 300 and the second annular wall portion 130 is provided with a second recess 310. The second protrusion 131 and the second recess 310 are engaged in a convex-concave engagement, thus allowing the first annular member 200 and the first annular wall portion 120 to be joined. The parts 120 and the second annular member 300 and the second annular wall part 130 are connected by a convex-concave fit. Alternatively, the first annular member 200 and the first annular wall part 120 can be connected by a convex-concave fit, and the second annular member 300 and the second annular wall part 130 can be connected by a thread. Or, conversely, the first annular member 200 and the first annular wall part 120 can be connected by a thread, and the second annular member 300 and the second annular wall part 130 can be connected by a convex-concave fit. Alternatively, the first annular member 200 and the first annular wall part 120, as well as the second annular member 300 and the second annular wall part 130, can all be connected by threads.

[0042] Please see Figures 1 to 4 In this application, the first annular member 200 and the first annular wall portion 120, as well as the second annular member 300 and the second annular wall portion 130, are connected by a snap-fit ​​structure. Specifically, as shown in the figure... Figures 1 to 3 As shown, in a specific embodiment of this application, a first protrusion 210 is provided at the bottom of the first annular member 200. The first protrusion 210 is a columnar annular boss. Correspondingly, a first recess 121 is provided at the top of the first annular wall portion 120. The first recess 121 is a columnar annular groove. The columnar annular boss and the columnar annular groove are inserted and engaged.

[0043] like Figure 1 , Figure 2 and Figure 4 As shown, the vertical plane passing through the axis of the graphite crucible for silicon carbide crystal growth is the longitudinal symmetry plane of the graphite crucible for silicon carbide crystal growth. The cross-sectional shape formed by the intersection of the second protrusion 131 and the second concave portion 310 with the longitudinal symmetry plane is triangular or trapezoidal. Specifically, the second concave portion 310 is provided at the bottom of the second annular member 300, and the second protrusion 131 is provided at the top of the second annular wall portion 130. Of course, the cross-sectional shapes of the second protrusion 131 and the second concave portion 310 described above are merely preferred embodiments provided in this application, and are not actually limited to this. Other cross-sectional shapes can also be used, and are not limited here.

[0044] As a preferred option, such as Figure 1 As shown, the inner circumferential surface of the first annular member 200 is flush with the inner circumferential surface of the first annular wall portion 120, and the outer circumferential surface of the first annular member 200 is flush with the outer circumferential surface of the first annular wall portion 120, so as to ensure that the outer sidewall of the graphite crucible for silicon carbide crystal growth does not have a stepped structure. The inner circumferential surface of the second annular member 300 is flush with the inner circumferential surface of the second annular wall portion 130, and the outer circumferential surface of the second annular member 300 is flush with the outer circumferential surface of the second annular wall portion 130, so as to ensure that the inner sidewall of the graphite crucible for silicon carbide crystal growth does not have a stepped structure.

[0045] It is foreseeable that the inner sidewall of the crucible is in direct contact with the material and is the area with the most severe corrosion and the most frequent replacement. Therefore, in order to further reduce costs, in one embodiment of this application, the thickness of the outer sidewall is greater than or equal to the thickness of the inner sidewall, that is, the thickness of the first annular member 200 and the first annular wall portion 120 is greater than the thickness of the second annular member 300 and the second annular wall portion 130. Of course, the reduction of the inner sidewall thickness needs to be carried out under the premise of ensuring strength.

[0046] Specifically, in one embodiment of this application, the thickness of the outer sidewall is 4mm to 8mm greater than the thickness of the inner sidewall, that is, the thickness of the first annular member 200 and the first annular wall portion 120 is 4mm to 8mm greater than the thickness of the second annular member 300 and the second annular wall portion 130.

[0047] Specifically, in this application, the graphite crucible for silicon carbide crystal growth is cylindrical in shape. The axial dimension of the graphite crucible for silicon carbide crystal growth, i.e., the height of the graphite crucible, is between 120mm and 160mm, the outer diameter is between 265mm and 280mm, the thickness of the crucible sidewall is between 25mm and 40mm, and the dimension of the cavity along the thickness direction of the crucible sidewall is between 3mm and 6mm.

[0048] During the growth of silicon carbide crystals, a graphite cap needs to be sealed at the top opening of the container cavity of the graphite crucible used for silicon carbide crystal growth. The container cavity is surrounded by the inner wall of the graphite crucible used for silicon carbide crystal growth. The seed crystal is assembled with the graphite cap facing the bottom of the container cavity, and the interior needs to support the silicon carbide raw material.

[0049] Furthermore, the first annular component 200 is formed by splicing multiple first ring bodies along the axial and / or radial direction of the graphite crucible for silicon carbide crystal growth. The first ring bodies can have the same or different structures. And / or, the second annular component 300 is formed by splicing multiple second ring bodies along the axial and / or radial direction of the graphite crucible for silicon carbide crystal growth. The second ring bodies can have the same or identical structure.

[0050] Specifically, in one embodiment of this application, at least the second annular member 300 is formed by stacking multiple identical second ring bodies sequentially along the axial direction of the graphite crucible for silicon carbide crystal growth. This allows the positions of the second ring bodies to be swapped according to their corrosion conditions, thereby further extending the service life of the second annular member 300 and reducing costs.

[0051] It should be noted that the graphite crucible for silicon carbide crystal growth provided in this application can be applied to various methods for growing silicon carbide crystals, such as physical vapor transport (PVT) and liquid phase epitaxy (LPE).

[0052] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," or "the" do not specifically refer to the singular and may include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0053] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0054] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0055] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A graphite crucible for growing silicon carbide crystals, characterized in that, include: A base member (100) includes a base bottom (110), a first annular wall portion (120), and a second annular wall portion (130). The first annular wall portion (120) rises from the periphery of the base bottom (110), and the second annular wall portion (130) is located inside the first annular wall portion (120) and is coaxially disposed on the base bottom (110) with the first annular wall portion (120). The first annular member (200) is detachably connected to one end of the first annular wall portion (120) away from the base (110), forming the outer wall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth; The second annular member (300) is detachably connected to one end of the second annular wall portion (130) away from the base (110), forming the inner sidewall of the crucible sidewall of the graphite crucible for silicon carbide crystal growth, and there is a cavity between the outer sidewall and the inner sidewall.

2. The graphite crucible for silicon carbide crystal growth according to claim 1, characterized in that, The first annular member (200) is threaded or snap-fitted to the first annular wall portion (120), and the second annular member (300) is threaded or snap-fitted to the second annular wall portion (130).

3. The graphite crucible for silicon carbide crystal growth according to claim 2, characterized in that, One of the first annular member (200) and the first annular wall portion (120) is provided with a first protrusion (210), and the other of the first annular member (200) and the first annular wall portion (120) is provided with a first recess (121). The first protrusion (210) and the first recess (121) are engaged in a convex-concave engagement. And / or, one of the second annular member (300) and the second annular wall portion (130) is provided with a second protrusion (131), and the other of the second annular member (300) and the second annular wall portion (130) is provided with a second recess (310). The second protrusion (131) and the second recess (310) are engaged in a convex-concave engagement.

4. The graphite crucible for silicon carbide crystal growth according to claim 3, characterized in that, The first protrusion (210) is a columnar annular boss, and the first concave part (121) is a columnar annular groove. The columnar annular boss and the columnar annular groove are inserted into each other.

5. The graphite crucible for silicon carbide crystal growth according to claim 3, characterized in that, The vertical plane passing through the axis of the graphite crucible for silicon carbide crystal growth is the longitudinal symmetry plane of the graphite crucible for silicon carbide crystal growth. The cross-sectional shape formed by the intersection of the second convex part (131) and the second concave part (310) with the longitudinal symmetry plane is a triangle or a trapezoid.

6. The graphite crucible for silicon carbide crystal growth according to any one of claims 1-5, characterized in that, The inner circumferential surface of the first annular member (200) is flush with the inner circumferential surface of the first annular wall portion (120), the outer circumferential surface of the first annular member (200) is flush with the outer circumferential surface of the first annular wall portion (120), the inner circumferential surface of the second annular member (300) is flush with the inner circumferential surface of the second annular wall portion (130), and the outer circumferential surface of the second annular member (300) is flush with the outer circumferential surface of the second annular wall portion (130).

7. The graphite crucible for silicon carbide crystal growth according to claim 6, characterized in that, The thickness of the outer sidewall is greater than or equal to the thickness of the inner sidewall.

8. The graphite crucible for silicon carbide crystal growth according to claim 7, characterized in that, The thickness of the outer sidewall is 4mm to 8mm greater than the thickness of the inner sidewall.

9. The graphite crucible for silicon carbide crystal growth according to any one of claims 1-5, characterized in that, The thickness of the crucible sidewall is 25mm to 40mm, and the dimension of the cavity along the thickness direction of the crucible sidewall is 3mm to 6mm.

10. The graphite crucible for silicon carbide crystal growth according to any one of claims 1-5, characterized in that, The first annular member (200) is formed by splicing multiple first ring bodies along the axial and / or radial direction of the graphite crucible for silicon carbide crystal growth, and / or the second annular member (300) is formed by splicing multiple second ring bodies along the axial and / or radial direction of the graphite crucible for silicon carbide crystal growth.

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