Crucible device for silicon carbide single crystal growth
By designing a crucible device including a cylindrical growth crucible, a built-in filter body and a limit block, the problems of silicon loss and carbon wrap during the growth of silicon carbide single crystals are solved, and the crystal quality and powder utilization rate are improved.
Patent Information
- Application Number
- CN202420817128.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-19
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-04-19
AI Technical Summary
The growth crucible used for single crystal growth of silicon carbide in the prior art has problems with silicon loss and graphitization of silicon carbide powder, resulting in Si/C ratio imbalance and the formation of carbon enclosures, affecting crystal quality.
A crucible device including a cylindrical growth crucible, a built-in filter body and a limit block is designed. The filter body reduces the gas transmission rate and reduces silicon loss by separating the silicon carbide powder into two layers, and the limiting block occupies the middle position, reducing heat inhomogeneity and improving powder utilization.
It effectively solves the silicon loss problem of silicon carbide powder, improves the growth quality of silicon carbide single crystals and the utilization rate of powder, and reduces production costs.
Smart Images
Figure CN222434684U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor growth, in particular to a crucible device for growing silicon carbide single crystals. Background Art
[0002] Compared with many other semiconductor single crystal materials, silicon carbide crystals have excellent properties such as high hardness, high thermal conductivity, large bandgap, high chemical stability, and strong radiation resistance. These excellent properties make it suitable for manufacturing high-temperature, high-frequency, and high-power devices, and have broad application prospects in the fields of radio frequency communications and satellite radar. Physical vapor transport is the most commonly used method for growing silicon carbide crystals. When heated to a certain temperature (such as 2100°C), the silicon carbide powder in the graphite crucible sublimates to form a gaseous environment for crystal growth, and is transported to the surface of the low-temperature silicon carbide seed crystal at the top of the crucible driven by the temperature gradient for recrystallization, thereby forming a silicon carbide single crystal.
[0003] In the prior art, the growth crucible used for the growth of silicon carbide single crystals is usually a straight-through structure. In the early stage of growth, the raw materials far away from the seed crystal will complete a large amount of gas transmission from the wall to the seed crystal, but will not generate silicon carbide single crystals. This is because the vapor pressure of silicon is higher than that of other components. The gas silicon reacts with the graphite wall of the crucible to generate Si2C and SiC2 and overflow the crucible, causing silicon loss, and ultimately causing an imbalance in the Si / C ratio that affects the growth components and the temperature field stability. In addition, the gas phase component is rich in silicon, making the unevaporated silicon carbide powder rich in carbon, thereby causing the graphitization of the silicon carbide powder. The graphitized solid carbon particles are transported to the growth surface, and carbon inclusions will be formed in the silicon carbide crystal, affecting the quality of the silicon carbide single crystal.
[0004] In addition, since high-purity silicon carbide powder is expensive, uneven radial heat transfer in the crucible can easily lead to uneven thermal field distribution, causing the temperature distribution of the silicon carbide powder to be high on the outside and low on the inside, resulting in less evaporation of powder in the middle part and low utilization rate. Utility Model Content
[0005] One purpose of the utility model is to provide a crucible device for growing silicon carbide single crystals, so as to solve the technical problem in the prior art that silicon carbide powder in the growth crucible is prone to silicon loss.
[0006] Another purpose of the utility model is to improve the utilization rate of silicon carbide powder.
[0007] According to the purpose of the utility model, the utility model provides a crucible device for growing silicon carbide single crystals, comprising:
[0008] A growth crucible in the shape of a cylinder;
[0009] A filter body is located in the growth crucible, the filter body comprises a cylindrical main body and an annular transverse plate, the bottom of the main body is connected to the bottom wall of the growth crucible, the transverse plate is connected between the growth crucible and the main body, so that a cavity is formed between the filter body and the growth crucible, and the main body is provided with an air flow channel;
[0010] A limit block is located in the inner space of the main body, and the limit block extends in a vertical direction and is attached to the bottom of the growth crucible.
[0011] Optionally, the transverse plate portion is arranged in a horizontal direction.
[0012] Optionally, the filter body is a porous graphite body with a porosity ranging from 30% to 80%.
[0013] Optionally, the limiting block is cylindrical and has a diameter ratio to the main body in a range of 1:2-1:3.
[0014] Optionally, the height ratio of the cavity to the silicon carbide powder is any value in the range of 1:1-1:3.
[0015] Optionally, the top of the transverse plate portion is flush with the top of the main body portion.
[0016] Optionally, the limit block is made of graphite material.
[0017] Optionally, it also includes:
[0018] A crucible cover, disposed on the top of the growth crucible, and the crucible cover and the growth crucible form a closed cavity;
[0019] The silicon carbide seed crystal is bonded to the bottom of the crucible cover.
[0020] Optionally, it also includes:
[0021] The induction coil is sleeved on the outer peripheral side of the growth crucible, so that the growth crucible and the limit block are inductively heated by the induction coil respectively.
[0022] Optionally, the limiting block is made integrally with the growth crucible.
[0023] The utility model divides the growth crucible into a cavity and an internal space by setting a filter body, that is, the filter body divides the silicon carbide powder into two layers, an inner layer and an outer layer. After the growth crucible is heated to a higher temperature, the silicon carbide powder located at the inner wall of the growth crucible is heated and gasified and gas is transmitted through the air flow channel of the filter body, so that the gas transmission rate of the silicon carbide powder located at the inner wall of the growth crucible is reduced, and the silicon loss problem of the silicon carbide powder in the growth crucible is effectively solved. The filter body can also filter the carbon particles and impurities transported by the sublimation of the powder, thereby preventing the carbon particles and impurity particles from being brought to the silicon carbide seed crystal, reducing various defects and dislocations such as carbon inclusions and microtubes during the crystal growth process, thereby improving the growth quality of the silicon carbide single crystal. In addition, the presence of the limit block can replace the silicon carbide powder that is not easily heated in the middle position of the growth crucible, which can reduce the amount of silicon carbide powder added, thereby improving the utilization rate of the silicon carbide powder and reducing production costs.
[0024] Furthermore, the growth crucible and the limit block of the utility model are both made of graphite material, that is, the limit block can be inductively heated with the induction coil of the crucible device, thereby improving the temperature uniformity of the silicon carbide powder in the growth crucible and further improving the utilization rate of the silicon carbide powder.
[0025] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:
[0027] Figure 1 is a schematic structural diagram of a crucible device according to an embodiment of the utility model;
[0028] Figure 2 is a schematic structural diagram of a crucible device according to another embodiment of the utility model;
[0029] Figure 3 It is a schematic structural diagram of a crucible device according to another embodiment of the utility model.
[0030] Reference numerals:
[0031] 100-crucible device, 10-growth crucible, 11-bottom wall, 12-side wall, 20-filter body, 21-main body, 22-transverse plate, 23-cavity, 30-limiting block, 40-crucible cover, 50-silicon carbide seed crystal, 60-induction coil, 70-silicon carbide powder. DETAILED DESCRIPTION
[0032] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0034] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.
[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.
[0036] Figure 1 Schematic diagram of the structure of a crucible device according to an embodiment of the present invention. Figure 1As shown, the utility model provides a crucible device 100 for growing silicon carbide single crystals. The crucible device 100 includes a cylindrical growth crucible 10, a filter body 20 located in the growth crucible 10, and a stopper 30 located in the inner space of the main body 21. The filter body 20 includes a cylindrical main body 21 and an annular transverse plate 22. The bottom of the main body 21 is connected to the bottom wall 11 of the growth crucible 10. The transverse plate 22 spans between the growth crucible 10 and the main body 21, so that a cavity 23 is formed between the filter body 20 and the growth crucible 10. The main body 21 is provided with an air flow channel. The stopper 30 extends in the vertical direction and is attached to the bottom of the growth crucible 10 to reduce the gas transmission rate of the silicon carbide powder 70 in the growth crucible 10, thereby reducing the silicon loss of the silicon carbide powder 70, while improving the utilization rate of the silicon carbide powder 70 and reducing the production cost.
[0037] In this embodiment, the growth crucible 10 is divided into a cavity 23 and an internal space by providing a filter body 20, that is, the filter body 20 divides the silicon carbide powder 70 into two layers, an inner layer and an outer layer. After the growth crucible 10 is heated to a higher temperature, the silicon carbide powder 70 located at the inner wall of the growth crucible 10 is heated and gasified and gas is transmitted through the air flow channel of the filter body 20, so that the gas transmission rate of the silicon carbide powder 70 located at the inner wall of the growth crucible 10 is reduced, and the silicon loss problem of the silicon carbide powder 70 in the growth crucible 10 is effectively solved. The filter body 20 can also filter the carbon particles and impurities transported by the powder sublimation, thereby preventing the carbon particles and impurity particles from being brought to the silicon carbide seed crystal 50, reducing various defects and dislocations such as carbon inclusions and microtubes during the crystal growth process, thereby improving the growth quality of the silicon carbide single crystal.
[0038] In this embodiment, the presence of the stopper 30 can occupy the middle position of the growth crucible 10, avoiding the problem of uneven heating of the silicon carbide powder 70 in the middle causing the formation of carbon inclusions, thereby preventing the silicon carbide single crystal from being contaminated by impurities in the carbon inclusions, improving the utilization rate of the silicon carbide powder 70, and reducing production costs. In addition, the utilization rate of the silicon carbide powder 70 can reduce the amount of carbon inclusions generated inside the silicon carbide powder 70 in the growth crucible 10, thereby reducing the amount of impurities generated and improving the growth quality of the silicon carbide single crystal.
[0039] In this embodiment, the transverse plate portion 22 of the filter body 20 allows the graphitized silicon carbide powder 70 to be completely covered in the cavity 23. After the graphitized silicon carbide powder 70 sublimates, it needs to pass through the transverse plate portion 22 and the main body 21 of the filter body 20 to reach the silicon carbide seed crystal 50 on the crucible cover 40, thereby reducing the crystallization amount of the graphitized silicon carbide powder 70 at the silicon carbide seed crystal 50 and improving the growth quality of the silicon carbide single crystal.
[0040] like Figure 1As shown, in this embodiment, the transverse plate portion 22 is arranged in the horizontal direction. Specifically, the transverse plate portion 22 of the filter body 20 is annular and parallel to the bottom wall 11 of the growth crucible 10, and the outer wall of the transverse plate portion 22 is attached to the side wall 12 of the growth crucible 10, and the inner wall of the transverse plate portion 22 is attached to the outer wall of the main body 21, so that a cavity 23 is formed between the transverse plate portion 22 and the growth crucible 10 and the main body 21 to reduce the gas transmission rate of the silicon carbide powder 70 in the growth crucible 10, thereby reducing the silicon loss of the silicon carbide powder 70. At the same time, the transverse plate portion 22 can also filter the carbon particles and impurities transported by the sublimation of the powder, thereby preventing the carbon particles and impurity particles from being brought to the seed crystal, and improving the growth quality of the silicon carbide single crystal.
[0041] In this embodiment, the filter body 20 is a porous graphite body, the porosity is any value in the range of 30%-80%, and the thickness is any value in the range of 2-6mm. Here, the pores in the porous graphite body are used as the above-mentioned air flow channel. Specifically, when the porosity is set to any value in the range of 30%-80%, the porosity is controlled uniformly, which is conducive to the decomposition of the silicon carbide powder 70 to form gas phase components, SiC(g), Si(g), Si2C(g), etc. escape uniformly from the porous graphite body, and can block the transfer of the carbonized graphite powder at the inner wall of the growth crucible 10 to the silicon carbide seed crystal 50. The porosity of the filter body 20 can be 30%, 50%, 70% or 80%, or any other value in the range of 30%-80%. The thickness of the filter body 20 is any value in the range of 2-6 mm. That is to say, the gaseous components generated by the heating of the silicon carbide powder 70 are transmitted to the upper space of the growth crucible 10 through the pores of the filter body 20, and finally transmitted to the position of the silicon carbide seed crystal 50 of the growth crucible 10, and are formed into a silicon carbide single crystal after cooling.
[0042] In a preferred embodiment, the porosity of the porous graphite body is set to 50%-70%.
[0043] In this embodiment, the stop block 30 is cylindrical and has a diameter ratio with the main body 21 in the range of 1:2-1:3, so that the utilization rate of the silicon carbide powder is improved and the graphitization effect of the edge of the powder is better. Specifically, the diameter ratio of the stop block 30 to the main body 21 is 1:2, 1:2.5 or 1:3, or any other value in the range of 1:2-1:3. In other embodiments, the stop block 30 can also be a cone, a cuboid or other shapes, and the structural shape of the stop block 30 can be set according to demand and is not limited here.
[0044] In this embodiment, the height ratio of the cavity 23 to the silicon carbide powder 70 is any value in the range of 1:1-1:3. Specifically, the height ratio of the cavity 23 to the silicon carbide powder 70 is 1:1, 1:2 or 1:3, or any other value in the range of 1:1-1:3. That is to say, since the temperature at the middle and lower position of the side wall 12 of the growth crucible 10 is relatively high, when the height ratio of the cavity 23 to the silicon carbide powder 70 is any value in the range of 1:1-1:3, the gas transmission rate of the silicon carbide powder 70 in the growth crucible 10 can be reduced, thereby reducing the silicon loss of the silicon carbide powder 70, while improving the utilization rate of the silicon carbide powder 70 and reducing the production cost.
[0045] Figure 2 is a schematic structural diagram of a crucible device according to another embodiment of the utility model, Figure 3 It is a schematic structural diagram of a crucible device according to another embodiment of the utility model.
[0046] like Figure 1 and Figure 2 As shown, in this embodiment, the top of the transverse plate portion 22 is flush with the top of the main body portion 21. Specifically, the transverse plate portion 22 of the filter body 20 is connected between the growth crucible 10 and the main body portion 21, and the top of the transverse plate portion 22 is flush with the top of the main body portion 21, so that a cavity 23 is formed between the filter body 20 and the growth crucible 10, and the gas phase components of the silicon carbide powder 70 are transmitted to the silicon carbide seed crystal 50 through the pores of the filter body 20, thereby reducing the gas transmission rate of the silicon carbide powder 70 in the growth crucible 10.
[0047] like Figure 2 As shown, in another embodiment, the height ratio of the cavity 23 to the silicon carbide powder 70 is 1:2, and the top of the cross plate portion 22 is flush with the top of the main body 21, that is, the height of the main body 21 of the filter body 20 is half of the height of the silicon carbide powder 70, which can reduce the gas transmission rate of the silicon carbide powder 70 in the growth crucible 10, thereby reducing the silicon loss of the silicon carbide powder 70 and reducing the manufacturing cost of the crucible device 100.
[0048] like Figure 3 As shown, in another embodiment, the height ratio of the cavity 23 to the silicon carbide powder 70 is 1:2, and the height ratio of the main body 21 of the filter body 20 to the silicon carbide powder 70 is 1:1, that is, the transverse plate portion 22 of the filter body 20 is located in the middle position of the main body 21, and the formed cavity 23 can reduce the gas transmission rate of the silicon carbide powder 70 in the growth crucible 10, and the protruding main body 21 can also block the graphite particles in the edge atmosphere of the upper side wall 12 of the growth crucible 10, thereby improving the growth quality of the silicon carbide single crystal.
[0049] In this embodiment, the stopper 30 is made of graphite material. Specifically, the stopper 30 and the induction coil 60 on the outer peripheral side of the crucible device 100 are inductively heated, so that the stopper 30 can directly heat the silicon carbide powder 70 at the middle position inside the growth crucible 10, thereby improving the heating uniformity of the silicon carbide powder 70 in the growth crucible 10.
[0050] In this embodiment, the crucible device 100 further includes a crucible cover 40 and a silicon carbide seed crystal 50. The crucible cover 40 is disposed on the top of the growth crucible 10, and the crucible cover 40 and the growth crucible 10 form a closed cavity 23, and the silicon carbide seed crystal 50 is bonded to the bottom of the crucible cover 40. Specifically, the silicon carbide seed crystal 50 is bonded to the bottom of the crucible cover 40 so that the silicon carbide seed crystal 50 grows toward the side away from the crucible cover 40. Here, the crucible cover 40 is configured as a solid cylindrical shape, the lower end of the crucible cover 40 abuts against the upper open end surface of the growth crucible 10, and the crucible cover 40 and the growth crucible 10 are tightly matched.
[0051] In this embodiment, the crucible cover 40 is arranged on the upper part of the growth crucible 10, and the upper opening of the growth crucible 10 is closed, so that the silicon carbide powder 70 is in a closed environment, and a thermal insulation layer is evenly coated on the outside of the growth crucible 10 and the crucible cover 40, and the crucible device 100 is placed in a high temperature environment of 2000-2400°C to prepare silicon carbide single crystals.
[0052] In this embodiment, the growth crucible 10 and the crucible cover 40 are both made of graphite material. The graphite material used must have high density, that is, by mechanically treating graphite with low porosity, a crucible structure with extremely high surface flatness can be obtained.
[0053] In this embodiment, the crucible device 100 further includes an induction coil 60, which is sleeved on the outer peripheral side of the growth crucible 10, so that the growth crucible 10 and the stop block 30 are respectively inductively heated by the induction coil 60. Specifically, the induction coil 60 and the growth crucible 10 are inductively heated, so that the growth crucible 10 is inductively heated, thereby heating the silicon carbide powder 70 located in the growth crucible 10. The induction coil 60 and the stop block 30 are inductively heated, so that the stop block 30 is inductively heated, thereby heating the silicon carbide powder 70 located in the middle position of the biochemical crucible, so as to improve the heating uniformity of the silicon carbide powder 70, thereby improving the utilization rate of the silicon carbide powder 70.
[0054] In this embodiment, the stopper 30 and the growth crucible 10 are made in one piece, which facilitates the mass production of the crucible device 100. In other embodiments, the stopper 30 and the growth crucible 10 are made separately.
[0055] In this embodiment, a filter body 20 is provided to divide the growth crucible 10 into a cavity 23 and an internal space, that is, the filter body 20 divides the silicon carbide powder 70 into two layers, an inner layer and an outer layer. After the growth crucible 10 is heated to a higher temperature, the silicon carbide powder 70 located at the inner wall of the growth crucible 10 is heated and vaporized and gas is transmitted through the air flow channel of the filter body 20, so that the gas transmission rate of the silicon carbide powder 70 located at the inner wall of the growth crucible 10 is reduced, thereby effectively solving the problem of silicon loss of the silicon carbide powder 70 in the growth crucible 10.
[0056] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0057] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.
Claims
1. A crucible device for growing silicon carbide single crystals, characterized in that: include: A growth crucible in the shape of a cylinder; A filter body is located in the growth crucible, the filter body comprises a cylindrical main body and an annular transverse plate, the bottom of the main body is connected to the bottom wall of the growth crucible, the transverse plate is connected between the growth crucible and the main body, so that a cavity is formed between the filter body and the growth crucible, and the main body is provided with an air flow channel; A limit block is located in the inner space of the main body, and the limit block extends in a vertical direction and is attached to the bottom of the growth crucible.
2. The crucible device according to claim 1, characterized in that The transverse plate portion is arranged along a horizontal direction.
3. The crucible device according to claim 2, characterized in that: The filter body is a porous graphite body, and the porosity is any value in the range of 30%-80%.
4. The crucible device according to claim 3, characterized in that: The limiting block is cylindrical and has a diameter ratio with respect to the main body in a range of 1:2-1:
3.
5. The crucible device according to claim 4, characterized in that: The height ratio of the cavity to the silicon carbide powder is any value in the range of 1:1-1:
3.
6. The crucible device according to claim 5, characterized in that The top of the transverse plate portion is flush with the top of the main body portion.
7. The crucible device according to any one of claims 1 to 6, characterized in that: The limiting block is made of graphite material.
8. The crucible device according to claim 7, characterized in that Also includes: A crucible cover, disposed on the top of the growth crucible, and the crucible cover and the growth crucible form a closed cavity; The silicon carbide seed crystal is bonded to the bottom of the crucible cover.
9. The crucible device according to claim 8, characterized in that Also includes: The induction coil is sleeved on the outer peripheral side of the growth crucible, so that the growth crucible and the limit block are inductively heated by the induction coil respectively.
10. The crucible device according to claim 1, characterized in that: The limiting block is made integrally with the growth crucible.