Growth crucible
By setting up barrier plates and filter blocks in the growth crucible to block the transport of silicon carbide atmosphere and carbon particles, the problems of polycrystalline and carbon encapsulation at the edge of silicon carbide single crystal are solved, and the quality and quality of single crystals are improved.
Patent Information
- Application Number
- CN202421104721.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-05-21
AI Technical Summary
In the prior art, silicon carbide single crystals are prone to form carbon inclusions and edge polycrystals during growth, and the center of silicon carbide seed crystals is less deposition, which affects the crystal quality, and the driving force of carbon particles and impurity particles affects the quality of the single crystals. .
A growth crucible is designed, including a crucible body, silicon carbide seed crystals, limit blocks, barrier discs and filter blocks. By setting barrier discs and filter blocks on the side wall of the crucible, the high-temperature silicon carbide atmosphere and the transport of carbon particles is blocked. Prevent edge growth and impurities from being driven by impurities, and improve the quality of single crystals.
It effectively prevents the formation of edge polycrystals and carbon encapsulation of silicon carbide single crystals, improves the growth quality of silicon carbide single crystals, reduces defects and dislocations in the crystals, and improves the quality of the single crystals.
Smart Images
Figure CN222251121U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of semiconductor growth, and in particular relates to a growth crucible. Background Art
[0002] Physical vapor transport is the most commonly used method for preparing silicon carbide crystals. When heated to a certain temperature, the silicon carbide powder in the graphite crucible sublimates to form a silicon carbide atmosphere. Driven by the temperature gradient, the silicon carbide atmosphere is transported to the surface of the low-temperature silicon carbide seed crystal at the top of the crucible for recrystallization, thereby forming a silicon carbide single crystal.
[0003] In the prior art, the silicon carbide powder is heated by a common induction power supply combined with a coil heating method. This heating method makes the side wall temperature of the growth crucible higher and the middle temperature lower, resulting in a fast sublimation rate of the silicon carbide powder near the side wall of the growth crucible and central recrystallization, which results in more silicon carbide single crystals deposited at the edge of the silicon carbide seed crystal and less deposited in the center, easily forming low-quality single crystals. In addition, as the silicon carbide powder sublimates, carbon particles and impurity particles will be brought to the silicon carbide seed crystal, seriously affecting the quality of the silicon carbide single crystal. Utility Model Content
[0004] One purpose of the utility model is to provide a growth crucible to solve the technical problems in the prior art that silicon carbide single crystals are prone to form carbon inclusions and polycrystals are prone to form on the edges of silicon carbide seed crystals.
[0005] Another object of the utility model is to improve the growth quality of silicon carbide single crystal.
[0006] According to the purpose of the utility model, the utility model provides a growth crucible, the growth crucible comprises a crucible body and a silicon carbide seed crystal, the bottom of the crucible body is filled with silicon carbide powder, the silicon carbide seed crystal is located at the top of the crucible body, and the growth crucible also comprises:
[0007] A limit block is located in the crucible body, the limit block extends in a vertical direction and fits with the bottom of the crucible body;
[0008] A baffle plate, comprising a main body, the main body is spaced a preset distance from the silicon carbide powder and abuts against a side wall of the growth crucible, and the main body is provided with a through hole;
[0009] A filter block is installed in the through hole, and the filter block is provided with an air flow channel so that the heated silicon carbide powder is transmitted to the silicon carbide seed crystal through the filter block.
[0010] Optionally, the height of the bottom surface of the main body portion gradually increases along the direction from the side wall of the crucible body to the through hole.
[0011] Optionally, an upward step surface is formed in the through hole, and the bottom of the filter block overlaps the step surface.
[0012] Optionally, the cross section of the through hole along the vertical plane is in the shape of an inverted trapezoid, and the diameter of the through hole is any value in the range of 50 mm-100 mm.
[0013] Optionally, the diameter ratio of the crucible body to the filter block is any value in the range of 1:0.5-1:0.3.
[0014] Optionally, the diameter ratio of the limiting block to the filtering block is any value in the range of 1:1-1:2.
[0015] Optionally, the diameter ratio of the limiting block to the crucible body is any value in the range of 1:2-1:3.
[0016] Optionally, the filter block is a porous graphite body with a porosity ranging from 30% to 90%.
[0017] Optionally, surfaces of the barrier disc, the limiting block and the filter block are provided with a metal coating.
[0018] Optionally, the material of the metal coating is a rare metal.
[0019] The growth crucible of the utility model is provided with a barrier disk in the crucible body that abuts against the side wall of the crucible body, and a filter block is provided at the through hole of the barrier disk, so that the silicon carbide atmosphere generated after the silicon carbide powder is heated at high temperature is transmitted to the silicon carbide seed crystal through the filter block. In other words, the barrier disk can block the transportation of the silicon carbide atmosphere in the high-temperature graphitization zone at the edge of the powder, prevent the growth rate of the seed crystal edge from being too fast and produce polycrystalline, and the filter block can block the transportation of carbon particles, prevent carbon particles and impurity particles from being brought to the silicon carbide seed crystal, thereby reducing various defects and dislocations such as carbon inclusions and microtubes during crystal growth, and improving the growth quality of silicon carbide single crystals.
[0020] Furthermore, the utility model provides a metal coating on the surface of the barrier plate, limit block and filter block of the growth crucible. Since the barrier plate, limit block and filter block are made of graphite, providing the metal coating on their surface can effectively block the transmission of carbon particles generated internally under high temperature conditions, and prevent the carbon particles from being transferred to the silicon carbide seed crystal, thereby improving the growth quality of the silicon carbide single crystal.
[0021] 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
[0022] 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:
[0023] Figure 1 is a schematic structural diagram of a growth crucible according to an embodiment of the utility model;
[0024] Figure 2 is a schematic top view of a growth crucible according to an embodiment of the present invention;
[0025] Figure 3 It is a schematic diagram of transmission of silicon carbide atmosphere according to an embodiment of the utility model.
[0026] Reference numerals:
[0027] 100-growth crucible, 200-silicon carbide powder, 10-crucible body, 20-silicon carbide seed crystal, 30-limiting block, 40-blocking plate, 50-filter block, 60-metal coating, 70-induction coil, 80-crucible cover, 41-main body, 42-step surface. DETAILED DESCRIPTION
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] Figure 1 is a schematic structural diagram of a growth crucible according to an embodiment of the utility model, Figure 2 is a schematic top view of a growth crucible according to an embodiment of the utility model, Figure 3 It is a schematic diagram of transmission of silicon carbide atmosphere according to an embodiment of the utility model.
[0033] like Figures 1 to 3 As shown, an embodiment of the utility model provides a growth crucible 100, which includes a crucible body 10 and a silicon carbide seed crystal 20, the bottom of the crucible body 10 is filled with silicon carbide powder 200, and the silicon carbide seed crystal 20 is located at the top of the crucible body 10. The growth crucible 100 is configured as a cylindrical tube, the bottom of the crucible body 10 is filled with silicon carbide powder 200, and the top is provided with a crucible cover 80, and the crucible cover 80 and the crucible body 10 together define a closed cavity for the growth of silicon carbide single crystals. The crucible cover 80 is configured as a solid cylinder, and the lower end of the crucible cover 80 abuts against the upper open end surface of the growth crucible 100, and the crucible cover 80 and the crucible body 10 are tightly and reliably matched.
[0034] In this embodiment, the growth crucible 100 further includes a stopper 30, a baffle plate 40 and a filter block 50. The stopper 30 is located in the crucible body 10. The stopper 30 extends in the vertical direction and fits with the bottom of the crucible body 10. The baffle plate 40 includes a main body 41. The main body 41 is spaced a preset distance from the silicon carbide powder 200 and abuts against the side wall of the growth crucible 100. The main body 41 is provided with a through hole. The filter block 50 is installed in the through hole. The filter block 50 is provided with an air flow channel so that the heated silicon carbide powder 200 is transmitted to the silicon carbide seed crystal 20 through the filter block 50. Here, the thickness of the filter block 50 is any value in the range of 2 mm-6 mm. The thickness of the filter block 50 is 2 mm, 4 mm or 6 mm, or any other value in the range of 2 mm-6 mm.
[0035] The growth crucible 100 of this embodiment is provided with a barrier disk 40 abutting against the side wall of the crucible body 10 in the crucible body 10, and a filter block 50 is provided at the through hole of the barrier disk 40, so that the silicon carbide atmosphere generated after the silicon carbide powder 200 is heated at high temperature is transmitted to the silicon carbide seed crystal 20 through the filter block 50. In other words, the barrier disk 40 can block the transportation of the silicon carbide atmosphere in the high-temperature graphitization zone at the edge of the powder, prevent the edge growth rate of the silicon carbide seed crystal 20 from being too fast and generating polycrystalline, and the filter block 50 can block the transportation of carbon particles, prevent carbon particles and impurity particles from being brought to the silicon carbide seed crystal 20, thereby reducing various defects and dislocations such as carbon inclusions and microtubes during crystal growth, and improving the growth quality of silicon carbide single crystals.
[0036] In one embodiment, the crucible body 10, the crucible cover 80, the barrier plate 40 and the limit block 30 are all made of graphite material. Since the graphite material used needs to have high density, that is, graphite with low porosity is mechanically treated, a crucible structure with extremely high surface flatness can be obtained.
[0037] In a further embodiment, the height of the bottom surface of the main body 41 gradually increases in the direction from the side wall of the crucible body 10 to the through hole. Specifically, the height of the bottom surface of the main body 41 near the side wall of the crucible body 10 is lower than the height of the bottom surface near the through hole, so that the silicon carbide atmosphere gathers from the edge to the center, and the silicon carbide atmosphere is transmitted to the center position of the silicon carbide seed crystal 20 through the through hole in the center of the main body 41. In other words, by adjusting the different through hole diameters and the height of the bottom surface of the main body 41, the convexity of the central crystal can be adjusted to control the crystal shape. Here, the edge thickness of the side wall of the baffle plate 40 near the crucible body is any value in the range of 5mm-50mm, and the edge thickness of the baffle plate 40 near the through hole is any value in the range of 1mm-10mm. For example, the edge thickness of the side wall of the barrier plate 40 close to the crucible body may be 5 mm, 15 mm, 30 mm or 50 mm, or any other value between 5 mm and 50 mm, and the edge thickness of the barrier plate 40 close to the through hole may be 1 mm, 4 mm, 7 mm, 10 mm, or any other value between 1 mm and 10 mm.
[0038] In a further embodiment, an upward step surface 42 is formed in the through hole, and the bottom of the filter block 50 overlaps the step surface 42. Specifically, the bottom of the filter block 50 overlaps the step surface 42, and the height of the bottom of the step surface 42 gradually increases along the edge of the through hole toward the center of the through hole, so that the silicon carbide atmosphere gathers from the edge to the center, and the silicon carbide atmosphere is transmitted upward through the filter block 50. The step surface 42 is used to receive the filter block 50 to prevent carbon particles from being transmitted to the silicon carbide seed crystal 20. At the same time, the bottom surface of the step surface 42 with increasing height can also guide the silicon carbide atmosphere to prevent the silicon carbide atmosphere on both sides of the crucible body 10 from being unable to be transmitted to the filter block 50.
[0039] In a further embodiment, the cross-section of the through hole along the vertical plane is an inverted trapezoid, and the diameter of the through hole is any value in the range of 50mm-100mm. Specifically, the cross-section at the top of the through hole is larger than the step surface 42, and the diameter of the through hole can regulate the convexity of the silicon carbide single crystal. The smaller the through hole diameter, the greater the convexity of the silicon carbide single crystal. Conversely, the larger the through hole diameter, the smaller the convexity of the silicon carbide single crystal. Here, the through hole is a circular through hole, and the diameter of the through hole is 50mm, 75mm or 100mm, or any other value in the range of 50mm-100mm. The diameter of the through hole can be adaptively set according to actual needs. In other embodiments, the through hole can also be other shapes.
[0040] In a further embodiment, the diameter ratio of the crucible body 10 to the filter block 50 is any value in the range of 1:0.5-1:0.3. Specifically, the filter block 50 is disposed directly below the silicon carbide seed crystal 20, and when the diameter ratio of the crucible body 10 to the filter block 50 is any of the above values, the silicon carbide atmosphere flowing through the filter block 50 can be transmitted to the center of the silicon carbide seed crystal 20. Here, the diameter ratio of the crucible body 10 to the filter block 50 is 1:0.5, 1:0.4 or 1:0.3, and can also be any other value in the range of 1:0.5-1:0.3.
[0041] In a further embodiment, the diameter ratio of the stop block 30 to the filter block 50 is any value in the range of 1:1-1:2. Specifically, the diameter ratio of the stop block 30 to the filter block 50 is 1:1, 1:1.5 or 1:2, and can also be any other value in the range of 1:1-1:2. When the diameter ratio of the stop block 30 to the filter block 50 is in the above range, the transmission efficiency of the silicon carbide atmosphere is the highest, and the stop block 30 is too small to cause recrystallization on the surface of the silicon carbide powder 200, which affects the transmission of the silicon carbide atmosphere from the inside of the silicon carbide powder 200 to the filter block 50, and the filter block 50 is too small to affect the transmission efficiency of the silicon carbide atmosphere, thereby avoiding affecting the growth rate of the silicon carbide single crystal.
[0042] In a further embodiment, the diameter ratio of the stopper 30 to the crucible body 10 is any value in the range of 1:2-1:3. Specifically, the diameter ratio of the stopper 30 to the crucible body 10 is 1:2, 1:2.5 or 1:3, or any other value in the range of 1:2-1:3. When the diameter ratio of the stopper 30 to the crucible body 10 is in the above range, it is possible to avoid the stopper 30 being too large, the silicon carbide powder 200 being filled less, and insufficient silicon carbide atmosphere supply.
[0043] In a further embodiment, the filter block 50 is a porous graphite body, and the porosity is any value in the range of 30%-90%. Specifically, the filter block 50 is a porous graphite body, and the graphite body itself has a plurality of channels for gas flow, so that the silicon carbide atmosphere is transmitted to the silicon carbide seed crystal 20 through the filter block 50. The porosity of the filter block 50 is designed to be in the range of 30%-90%, and the porosity is controlled uniformly, which is conducive to the uniform escape of the silicon carbide atmosphere formed by the decomposition of the silicon carbide powder 200 from the porous graphite body, and can be used to block the carbonized graphite powder from being transmitted to the silicon carbide seed crystal 20, thereby improving the growth quality of the silicon carbide single crystal. Here, the porosity of the filter block 50 is 30%, 50%, 70% or 90%, and can also be any other value in the range of 30%-90%.
[0044] In a preferred embodiment, the porosity of the filter block 50 is anywhere in the range of 50%-70%.
[0045] In a further embodiment, the surfaces of the blocking disc 40, the stop block 30 and the filter block 50 are provided with a metal coating 60. Specifically, the metal coating 60 is a high temperature resistant metal compound coating, and the metal coating 60 is coated on the upper and lower surfaces of the blocking disc 40, the stop block 30 and the filter block 50 to form a protective film to prevent the carbon particles in the graphite material in the blocking disc 40, the stop block 30 and the filter block 50 from affecting the growth of the silicon carbide single crystal.
[0046] In a further embodiment, the material of the metal coating 60 is a rare metal. Specifically, the metal compound coating is a carbide of a rare metal or a nitride of a rare metal or a mixture thereof, and the rare metal may be tantalum, titanium, niobium, hafnium, tungsten, zirconium or vanadium. Since the melting point of the metal compound is higher than the sublimation temperature of silicon carbide and it is chemically inert relative to silicon at the sublimation temperature of silicon carbide, and the thermal expansion coefficient of the metal compound is close to that of graphite, cracks between graphite and the metal coating 60 are avoided at the sublimation temperature.
[0047] In a further embodiment, the stopper 30 is made integrally with the crucible body 10 or separately, and the stopper 30 is attached to the bottom of the crucible body 10. The stopper 30 can occupy the middle position of the crucible body 10, thereby avoiding the problem of uneven heating of the silicon carbide powder 200 in the middle, which leads to the formation of carbon inclusions. The stopper 30 of this embodiment is a cylinder, and in other embodiments, the stopper 30 is set as a cone, and the shape of the stopper 30 is not specifically limited.
[0048] In a further embodiment, the height ratio of the stopper 30 to the silicon carbide powder 200 is any value in the range of 1:0.8-1:2. Specifically, the height ratio of the stopper 30 to the silicon carbide powder 200 is 1:0.8, 1:1, 1:1.5 or 1:2, or any other value in the range of 1:0.8-1:2.
[0049] In a further embodiment, the growth crucible 100 also includes an induction coil 70, which is sleeved on the outer peripheral side of the crucible body 10. The induction coil 70 and the limit block 30 are inductively heated, so that the limit block 30 can directly heat the silicon carbide powder 200 located on the side of the limit block 30, thereby improving the heating uniformity of the silicon carbide powder 200, avoiding the situation where the silicon carbide powder 200 is heated unevenly to produce carbon inclusions, and at the same time inhibiting the recrystallization phenomenon of the surface of the silicon carbide powder 200, thereby improving the crystal quality and the utilization rate of the powder, and reducing the production cost.
[0050] When assembling the growth crucible 100, first fix the silicon carbide seed crystal 20 on the crucible cover 80, place the limit block 30 in the middle of the bottom of the crucible body 10, and fill the bottom of the crucible body 10 with silicon carbide powder 200 and compact it, then fix the baffle plate 40 to the side wall of the crucible body 10, and the through hole of the baffle plate 40 is provided with a step surface 42, and then place the filter block 50 on the step surface 42 of the baffle plate 40, and finally set the crucible cover 80 on the top of the crucible body 10, close the top opening of the crucible body 10, so that the silicon carbide powder 200 is in a closed cavity, and place the growth crucible 100 in a high temperature environment with a temperature of 2000-2400°C to prepare silicon carbide single crystals.
[0051] 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.
[0052] 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 growth crucible, comprising a crucible body and a silicon carbide seed crystal, wherein the bottom of the crucible body is filled with silicon carbide powder, and the silicon carbide seed crystal is located at the top of the crucible body, characterized in that: The growth crucible also includes: A limit block is located in the crucible body, the limit block extends in a vertical direction and fits with the bottom of the crucible body; A baffle plate, comprising a main body, the main body is spaced a preset distance from the silicon carbide powder and abuts against a side wall of the growth crucible, and the main body is provided with a through hole; A filter block is installed in the through hole, and the filter block is provided with an air flow channel so that the heated silicon carbide powder is transmitted to the silicon carbide seed crystal through the filter block.
2. The growth crucible according to claim 1, characterized in that The height of the bottom surface of the main body portion gradually increases along the direction from the side wall of the crucible body to the through hole.
3. The growth crucible according to claim 2, characterized in that: An upward step surface is formed in the through hole, and the bottom of the filter block overlaps the step surface.
4. The growth crucible according to claim 3, characterized in that The cross section of the through hole along the vertical plane is in an inverted trapezoidal shape, and the diameter of the through hole is any value in the range of 50 mm-100 mm.
5. The growth crucible according to claim 4, characterized in that The diameter ratio of the crucible body to the filter block is any value in the range of 1:0.5-1:0.
3.
6. The growth crucible according to claim 5, characterized in that The diameter ratio of the limiting block to the filtering block is any value in the range of 1:1-1:
2.
7. The growth crucible according to claim 6, characterized in that The diameter ratio of the limiting block to the crucible body is any value in the range of 1:2-1:
3.
8. The growth crucible according to claim 7, characterized in that The filter block is a porous graphite body, and the porosity is any value in the range of 30%-90%.
9. The growth crucible according to any one of claims 1 to 8, characterized in that The surfaces of the blocking disc, the limiting block and the filtering block are provided with a metal coating.
10. The growth crucible according to claim 9, characterized in that The material of the metal coating is a rare metal.