Crystal growth apparatus and crystal growth method with silicon supplement and temperature regulation functions

Abstract

The present invention provides a crystal growth apparatus and a crystal growth method with both silicon supplementing and temperature regulating functions, which relate to the semiconductor field. In this crystal growth apparatus and method, a lifting partition is additionally arranged inside the crucible body, tantalum silicide in solid state is filled between the bottom wall of the crucible body and the lifting partition, and silicon carbide powder is filled above the lifting partition. During the crystal growth process, the solid tantalum silicide can be gradually melted into liquid tantalum silicide and flow through a plurality of through holes on the lifting partition to contact the silicon carbide powder on the upper surface of the lifting partition, thereby realizing automatic silicon supplementation and ensuring the balance and supersaturation of the silicon component and the carbon component as much as possible. At the same time, the lifting partition and the silicon carbide powder thereon will gradually descend, thereby gradually increasing the distance between the silicon carbide powder and the growth surface of the crystal to make up for the loss of the material-crystal distance due to the continuous descent of the growth surface of the crystal, and ensuring that the temperature gradient of the growth surface of the crystal is as stable as possible, that is, having both silicon supplementing and temperature regulating functions.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and more particularly to a crystal growth apparatus and a crystal growth method having both silicon replenishment and temperature regulation functions. Background Art

[0002] In the prior art, in a silicon carbide crystal growth apparatus based on the PVT (Physical Vapor Transport) method, a silicon replenishment structure and a temperature regulation structure are common auxiliary structures. The silicon replenishment structure can replenish silicon in the middle and late stages of crystal growth to adjust the balance and supersaturation of carbon and silicon components. The temperature regulation structure can adjust the distance between the crystal growth surface and the silicon carbide powder (i.e., the powder-crystal distance), thereby adjusting the temperature gradient in the region where the crystal growth surface is located, making the temperature gradient as stable as possible, and thus ensuring the crystal growth rate and quality.

[0003] After research by the inventor, it is found that most of the silicon replenishment structure and temperature regulation structure in the prior art achieve their respective purposes through mechanical structures at the bottom of the crucible. However, the space below the crucible is limited, and interference and contradictions are likely to occur in the control and cooperation between different mechanical structures. Therefore, they are usually arranged alternatively in the same crystal growth apparatus. Correspondingly, the existing crystal growth apparatus cannot have both the functions of silicon replenishment and temperature regulation. Summary of the Invention

[0004] An object of the present invention is to provide a crystal growth apparatus and a crystal growth method having both silicon replenishment and temperature regulation functions, which can have both silicon replenishment and temperature regulation functions, and effectively ensure the growth rate and quality of silicon carbide crystals.

[0005] Embodiments of the present invention may be implemented as follows:

[0006] In a first aspect, the present invention provides a crystal growth apparatus having both silicon replenishment and temperature regulation functions, which includes:

[0007] A crucible, the crucible includes a crucible lid and a crucible body, and the crucible lid is disposed on the top of the crucible body in an openable and closable manner;

[0008] A seed crystal, the seed crystal is disposed on the inner wall of the crucible lid and is used for growing silicon carbide crystals;

[0009] A lifting partition plate, the lifting partition plate is disposed in the crucible body in a liftable manner, and a plurality of through holes are formed in the lifting partition plate, and the upper surface of the lifting partition plate is used for carrying silicon carbide powder;

[0010] Solid tantalum silicide, the solid tantalum silicide is filled between the bottom wall of the crucible body and the lifting partition plate, and the solid tantalum silicide is used to support the lower surface of the lifting partition plate and is used to gradually melt into liquid tantalum silicide during crystal growth and flow to the upper surface of the lifting partition plate through the plurality of through holes.

[0011] In an alternative embodiment, a guiding column is provided at the center of the bottom wall of the crucible body. The guiding column is perpendicular to the bottom wall of the crucible body. A guiding hole is provided at the center of the lifting partition plate, and the guiding hole is in sliding fit with the guiding column.

[0012] In an alternative embodiment, a first planar portion is provided on the circumferential wall of the guiding column, and a second planar portion is provided on the inner wall of the guiding hole. The second planar portion is in sliding fit with the first planar portion.

[0013] In an alternative embodiment, the circumferential wall of the lifting partition plate is in sliding fit with the inner surface of the circumferential wall of the crucible body.

[0014] In an alternative embodiment, the plurality of through holes are arranged at intervals along both the circumferential direction and the radial direction of the lifting partition plate.

[0015] In an alternative embodiment, along the direction from the center to the edge of the lifting partition plate, the aperture of the through hole gradually increases.

[0016] In an alternative embodiment, both the crucible body and the crucible cover are made of graphite, and a tantalum carbide coating is provided on the inner wall of the crucible body.

[0017] In an alternative embodiment, a flow guiding cover is provided on the inner wall of the crucible body. The internal channel of the flow guiding cover includes a cylindrical section and a conical section that are connected in sequence from top to bottom. The cylindrical section is used to accommodate the seed crystal, and the diameter of the conical section gradually increases from top to bottom.

[0018] In an alternative embodiment, the flow guiding cover is made of tantalum carbide.

[0019] In a second aspect, the present invention provides a crystal growth method based on the crystal growth device with both silicon supplementing and temperature regulating functions according to any one of the foregoing embodiments, including:

[0020] Loading the solid tantalum silicide at the bottom of the crucible body;

[0021] Placing the lifting partition plate in a liftable manner inside the crucible body and supporting it on the solid tantalum silicide;

[0022] Loading the silicon carbide powder on the upper surface of the lifting partition plate;

[0023] Covering the crucible cover provided with the seed crystal and heating the crucible.

[0024] The beneficial effects of the crystal growth device and the crystal growth method with both silicon supplementing and temperature regulating functions provided by the present invention include:

[0025] The crystal growth device and method add a lifting partition inside the crucible body, fill solid tantalum silicide between the bottom wall of the crucible body and the lifting partition, fill silicon carbide powder above the lifting partition. During the crystal growth process, the solid tantalum silicide can gradually melt into liquid tantalum silicide. Under the gravitational extrusion of the silicon carbide powder and the lifting partition, the liquid tantalum silicide will flow through multiple through-holes on the lifting partition to the upper surface of the lifting partition to contact the silicon carbide powder, thereby reacting with the excess carbon component to generate a tantalum silicon carbon ternary compound, so as to fix the excess carbon component while realizing automatic silicon supplementation, and as much as possible ensure the balance and supersaturation of the silicon component and the carbon component. At the same time, the lifting partition and the silicon carbide powder on it will gradually descend, thereby gradually increasing the distance between the silicon carbide powder and the growth surface of the crystal, so as to make up for the loss of the material-crystal distance due to the continuous descent of the growth surface of the crystal, and ensure that the temperature gradient in the area where the growth surface of the crystal is located is as stable as possible. That is, the crystal growth device and method of the present invention have both the functions of silicon supplementation and temperature regulation, and can effectively ensure the growth rate and quality of silicon carbide crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a schematic structural diagram of the crystal growth device with the functions of silicon supplementation and temperature regulation provided in this embodiment before the tantalum silicide melts;

[0028] Figure 2 It is a top view of the lifting partition provided by an embodiment of the present invention;

[0029] Figure 3 It is a schematic structural diagram of the crystal growth device with the functions of silicon supplementation and temperature regulation provided in this embodiment after the tantalum silicide melts.

[0030] ICON:

[0031] 100 - crucible; 110 - crucible body; 120 - crucible cover; 122 - seed crystal; 124 - silicon carbide crystal; 200 - lifting partition; 210 - through-hole; 220 - guiding hole; 222 - second planar part; 300 - tantalum silicide; 400 - guiding column; 410 - first planar part; 500 - diversion cover; 510 - cylindrical section; 520 - conical section; 600 - silicon carbide powder. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0034] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings.

[0035] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner", "outer", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is customarily placed during use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0036] It should be noted that the features in the embodiments of the present invention can be combined with each other without conflict.

[0037] In the prior art, for a silicon carbide crystal growth device based on the PVT method, a silicon replenishment structure and a temperature adjustment structure are usually provided. Among them, the silicon replenishment structure is used to supplement silicon components into the crucible in the middle and late stages of crystal growth, so as to make up for the deficiency of silicon components in the middle and late stages of crystal growth, maintain the balance of carbon components and silicon components as much as possible, and ensure the growth rate and quality of silicon carbide crystals. The temperature adjustment structure is used to adjust the temperature gradient in the region where the growth surface of the silicon carbide crystal is located, so that it remains as constant as possible, thereby ensuring the growth rate and quality of the silicon carbide crystal. Because as the silicon carbide crystal grows, its growth surface continuously descends, and the distance from the silicon carbide powder must continuously decrease, resulting in continuous changes in the temperature gradient in the region where the growth surface of the silicon carbide crystal is located. The temperature adjustment structure can make it as constant as possible by adjusting the distance between the growth surface of the silicon carbide crystal and the silicon carbide powder (i.e., the distance between the material and the crystal), thereby maintaining the stability of the temperature gradient in the region where the growth surface of the silicon carbide crystal is located.

[0038] However, in the prior art, the silicon filling structure and the temperature adjustment structure are usually relatively complex, and both need to achieve the corresponding purpose through the mechanical structure at the bottom of the crucible, but the space below the crucible is limited, and the control and coordination between different mechanical structures are prone to interference and contradiction. Therefore, the silicon carbide crystal growth device in the prior art cannot be equipped with a silicon filling structure and a temperature adjustment structure at the same time, that is, the silicon filling function and the temperature adjustment function can only be selected one or the other, not both.

[0039] In view of the above situation, the present invention provides a new crystal growth device, which is additionally filled with solid tantalum silicide inside the crucible and a lifting baffle with through holes is set to support the tantalum silicide, and silicon carbide powder is filled on the upper surface of the lifting baffle. During the crystal growth process, the solid tantalum silicide will gradually melt to form liquid tantalum silicide, and then flow through the lifting baffle through multiple through holes to the silicon carbide powder. On the one hand, this can realize the supplement of silicon components in the middle and late stages of crystal growth, and on the other hand, it can also realize the gradual decline of silicon carbide powder with the lifting baffle, thereby compensating for the loss of material crystal distance caused by the gradual decline of the growth surface of the silicon carbide crystal, and then maintaining the temperature gradient of the area where the growth surface of the silicon carbide crystal is located stable, that is, it has both silicon supplement and temperature regulation functions.

[0040] In order to better understand the crystal growth device provided by the present invention, the overall structure, working principle and technical effects of the crystal growth device will be described in detail below with reference to the accompanying drawings.

[0041] Please refer to Figure 1 and Figure 2 The crystal growth device with both silicon replenishment and temperature adjustment functions provided by the present invention comprises a crucible 100, a seed crystal 122, a lifting partition 200 and solid tantalum silicide 300. The crucible 100 comprises a crucible cover 120 and a crucible body 110, and the crucible cover 120 is openably and closably arranged on the top of the crucible body 110. The seed crystal 122 is arranged on the inner wall of the crucible cover 120 for growing silicon carbide crystals 124. The lifting partition 200 is liftably arranged in the crucible body 110, and a plurality of through holes 210 are opened on the lifting partition 200, and the upper surface of the lifting partition 200 is used to carry silicon carbide powder 600. Solid tantalum silicide 300 is filled between the bottom wall of the crucible body 110 and the lifting baffle 200. The solid tantalum silicide 300 is used to support the lower surface of the lifting baffle 200 and to gradually melt to form liquid tantalum silicide 300 during crystal growth and flow to the upper surface of the lifting baffle 200 through multiple through holes 210.

[0042] Among them, the crucible body 110 and the crucible lid 120 of this embodiment can both be made of graphite, and a tantalum carbide coating (not shown in the figure) is provided on the inner wall of the crucible body 110. The function of setting the tantalum carbide coating is to improve the corrosion resistance of the inner wall of the crucible body 110, thereby extending the service life of the crucible 100.

[0043] In order to improve the utilization rate of the silicon carbide powder 600 and increase the growth rate of the silicon carbide crystal 124, in this embodiment, a flow guide cover 500 is provided on the inner side of the peripheral wall of the crucible body 110. The internal passage of the flow guide cover 500 includes a cylindrical section 510 and a conical section 520 that are connected in sequence from top to bottom. The cylindrical section 510 is used to accommodate the seed crystal 122, and the diameter of the conical section 520 gradually increases from top to bottom. In this way, the gas-phase crystal growth components formed by the sublimation of the silicon carbide powder 600 can be guided to flow towards the seed crystal 122, and at the same time, the growth shape of the silicon carbide crystal 124 can also be restricted. Further, the flow guide cover 500 is made of tantalum carbide to improve its corrosion resistance and extend its service life.

[0044] Please refer to Figure 2 again. A guide post 400 is provided at the center of the bottom wall of the crucible body 110, and the guide post 400 is perpendicular to the bottom wall of the crucible body 110. The lifting partition 200 can be liftably arranged inside the crucible body 110 in different ways as needed. In this embodiment, a guide hole 220 is provided at the center of the lifting partition 200, and the guide hole 220 is slidably matched with the guide post 400. Moreover, the peripheral wall of the lifting partition 200 is slidably matched with the inner surface of the peripheral wall of the crucible body 110. In this way, the lifting partition 200 can maintain a horizontal state as much as possible during the lifting process, so as to ensure that the silicon carbide powder 600 on the lifting partition 200 has as equal a height at different positions as possible. Furthermore, it can ensure that the distances between the silicon carbide powder 600 and the growth surface of the silicon carbide crystal 124 at different positions (i.e., the powder-seed distances at different positions) are as equal as possible. In this way, it is beneficial to make the temperature gradients at various positions in the region where the growth surface of the silicon carbide crystal 124 is located as the same as possible, so as to ensure that the growth rates at various positions of the silicon carbide crystal 124 are uniform, thereby ensuring the growth quality and reducing the generation of crystal defects.

[0045] In order to further maintain the stability and horizontality of the lifting partition 200 during the lifting process, in this embodiment, a first planar portion 410 is provided on the peripheral wall of the guide post 400, and a second planar portion 222 is provided on the inner wall of the guide hole 220. The second planar portion 222 is slidably matched with the first planar portion 410. In this way, the reliability and guiding property of the sliding fit between the guide post 400 and the guide hole 220 can be further improved, so that the lifting partition 200 can be lifted and lowered stably while maintaining a horizontal state.

[0046] It should be noted that in other embodiments, the lifting partition 200 can also achieve stability during the lifting process only by the sliding fit between its peripheral wall and the inner surface of the peripheral wall of the crucible body 110, without providing the guide posts 400 and the guide holes 220; alternatively, the lifting partition 200 can also achieve stability during the lifting process only through the guide posts 400 and the guide holes 220, and there can be a certain distance between its peripheral wall and the inner surface of the peripheral wall of the crucible body 110 without contact.

[0047] The multiple through holes 210 on the lifting partition 200 can be arranged as needed. In this embodiment, the multiple through holes 210 are arranged at intervals along both the circumferential and radial directions of the lifting partition 200 to improve the efficiency of the liquid tantalum silicide 300 passing through the through holes 210 to reach the upper surface of the lifting partition 200, thereby improving the silicon replenishment efficiency.

[0048] In addition, along the direction from the center to the edge of the lifting partition 200, the aperture of the through hole 210 gradually increases. That is, the closer to the edge of the lifting partition 200, the larger the aperture of the through hole 210 (but not larger than the particle size of the silicon carbide powder itself to avoid the silicon carbide powder from falling in). Such a setting can make the silicon replenishment efficiency at the edge position of the lifting partition 200 higher than that at the center position, so as to make up for the problem that the edge position lacks silicon components more than the center position due to the faster sublimation efficiency of the silicon carbide powder 600 at the edge position than at the center position.

[0049] The working principle and technical effects of the crystal growth device with both silicon replenishment and temperature regulation functions provided in this embodiment are specifically as follows:

[0050] During the crystal growth process, the solid tantalum silicide 300 can gradually melt into the liquid tantalum silicide 300, and under the gravity extrusion of the silicon carbide powder 600 and the lifting partition 200, the liquid tantalum silicide 300 will flow through the multiple through holes 210 on the lifting partition 200 to the upper surface of the lifting partition 200 and contact the silicon carbide powder 600 (see Figure 3 ), so as to react with the excess carbon components to generate tantalum silicon carbon ternary compounds, so as to fix the excess carbon components while realizing automatic silicon replenishment, and as much as possible ensure the balance and supersaturation of silicon components and carbon components. At the same time, the lifting partition 200 and the silicon carbide powder 600 thereon will gradually descend, so as to gradually increase the distance between the silicon carbide powder 600 and the crystal growth surface, so as to make up for the loss of the material crystal distance due to the continuous descent of the crystal growth surface, and ensure that the temperature gradient in the area where the crystal growth surface is located is as stable as possible. That is, the present crystal growth device and method have both the functions of silicon replenishment and temperature regulation, and can effectively ensure the growth rate and quality of the silicon carbide crystal 124.

[0051] It should also be noted that the filling height of the solid tantalum silicide 300 affects the descending height of the lifting partition plate 200, while the filling height of the silicon carbide powder 600 affects the growth thickness of the crystal (i.e., the loss amount of the material-crystal distance). The descending height of the lifting partition plate 200 should be as consistent as possible with the growth thickness of the crystal, so as to keep the material-crystal distance unchanged as much as possible and ensure the continuous stability of the temperature gradient in the area where the crystal growth surface is located. Based on this, in this embodiment, the filling height of the solid tantalum silicide 300 is less than or equal to 40% of the filling height of the silicon carbide powder 600, preferably 18% or 23%.

[0052] The present invention also provides a crystal growth method, which is used for the crystal growth device having both silicon supplementing and temperature regulating functions as described above. This crystal growth method includes the following steps:

[0053] Step S100: Fill the solid tantalum silicide 300 at the bottom of the crucible body 110.

[0054] Step S200: Place the lifting partition plate 200 in a liftable manner inside the crucible body 110 and support it on the solid tantalum silicide 300.

[0055] Step S300: Fill the silicon carbide powder 600 on the upper surface of the lifting partition plate 200.

[0056] Step S400: Cover the crucible cover 120 provided with the seed crystal 122 and heat the crucible 100.

[0057] By adopting the above crystal growth method, it is possible to simultaneously achieve the automatic supplement of silicon components during the growth process of the silicon carbide crystal 124 and the temperature regulation of the crystal growth surface, that is, it has both the functions of silicon supplementing and temperature regulating.

[0058] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A crystal growth device with both silicon supplement and temperature regulation functions, characterized in that, Comprising: A crucible (100), the crucible (100) includes a crucible lid (120) and a crucible body (110), the crucible lid (120) is disposed on top of the crucible body (110) in an openable and closable manner; A seed crystal (122), the seed crystal (122) is disposed on the inner wall of the crucible lid (120) for growing a silicon carbide crystal (124); A lifting partition plate (200), the lifting partition plate (200) is disposed in the crucible body (110) in a liftable manner, a plurality of through holes (210) are formed on the lifting partition plate (200), and the upper surface of the lifting partition plate (200) is used for carrying silicon carbide powder (600); Solid tantalum silicide (300), the solid tantalum silicide (300) is filled between the bottom wall of the crucible body (110) and the lifting partition plate (200), the solid tantalum silicide (300) is used for supporting the lower surface of the lifting partition plate (200) and for gradually melting during crystal growth to form liquid tantalum silicide (300) and flowing through the plurality of through holes (210) to the upper surface of the lifting partition plate (200); A guide post (400) is disposed at the center of the bottom wall of the crucible body (110), the guide post (400) is perpendicular to the bottom wall of the crucible body (110), a guide hole (220) is disposed at the center of the lifting partition plate (200), and the guide hole (220) is in sliding fit with the guide post (400).

2. The crystal growth apparatus with the functions of silicon supplement and temperature regulation according to claim 1, characterized in that A first planar portion (410) is disposed on the peripheral wall of the guide post (400), a second planar portion (222) is disposed on the inner wall of the guide hole (220), and the second planar portion (222) is in sliding fit with the first planar portion (410).

3. The crystal growth apparatus with the functions of silicon supplementation and temperature regulation according to claim 1, characterized in that, The peripheral wall of the lifting partition plate (200) is in sliding fit with the inner surface of the peripheral wall of the crucible body (110).

4. The crystal growth device with silicon supplement and temperature regulation functions according to claim 1, characterized in that The plurality of through holes (210) are arranged at intervals along both the circumferential direction and the radial direction of the lifting partition plate (200).

5. The crystal growth apparatus with the functions of silicon replenishment and temperature regulation according to claim 4, characterized in that, Along the direction from the center to the edge of the lifting partition plate (200), the aperture of the through hole (210) gradually increases.

6. The crystal growth apparatus with the functions of silicon supplementation and temperature adjustment according to claim 1, characterized in that, Both the crucible body (110) and the crucible lid (120) are made of graphite, and a tantalum carbide coating is disposed on the inner wall of the crucible body (110).

7. The crystal growth apparatus with the functions of silicon supplementation and temperature regulation according to claim 1, characterized in that, A flow guide cover (500) is disposed on the inner wall of the crucible body (110), the internal channel of the flow guide cover (500) includes a cylindrical section (510) and a conical section (520) that are connected in sequence from top to bottom, the cylindrical section (510) is used for accommodating the seed crystal (122), and the diameter of the conical section (520) gradually increases from top to bottom.

8. The crystal growth apparatus with both silicon supplement and temperature regulation functions according to claim 7, characterized in that, The flow guide cover (500) is made of tantalum carbide.

9. A crystal growth method, based on the crystal growth apparatus having both silicon supplementation and temperature regulation functions according to any one of claims 1-8, characterized in that, Comprising: Loading the solid tantalum silicide (300) at the bottom of the crucible body (110); Placing the lifting partition plate (200) in the crucible body (110) in a liftable manner and supporting it on the solid tantalum silicide (300); Loading the silicon carbide powder (600) on the upper surface of the lifting partition plate (200); Cover the crucible lid (120) provided with the seed crystal (122), and heat the crucible (100).

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