Crystal growth device with silicon supplementing and temperature adjusting functions and crystal growth method

Abstract

The invention provides a crystal growth device with silicon supplementing and temperature adjusting functions and a crystal growth method, and relates to the field of semiconductors. According to the crystal growth device and method, a lifting partition plate is additionally arranged in a crucible body, and the space between the bottom wall of the crucible body and the lifting partition plate is filled with solid tantalum silicide; the silicon carbide powder is filled above the lifting partition plate, in the crystal growth process, solid tantalum silicide can be gradually melted into liquid tantalum silicide, and the liquid tantalum silicide flows to the upper surface of the lifting partition plate through the through holes in the lifting partition plate to make contact with the silicon carbide powder, so that automatic silicon supplementing is achieved; and the balance and the supersaturation degree of the silicon component and the carbon component are ensured as far as possible. Meanwhile, the lifting partition plate and the silicon carbide powder on the lifting partition plate can gradually descend, so that the distance between the silicon carbide powder and the growth surface of the crystal is gradually increased, the material crystal distance lost due to continuous descending of the growth surface of the crystal is compensated, the temperature gradient of the growth surface of the crystal is ensured to be as stable as possible, and the silicon supplementing and temperature adjusting functions are achieved.

Description

Technical Field

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

[0002] In the prior art, in the silicon carbide crystal growth device based on the PVT (physical vapor transport) method, the silicon supplement structure and the temperature control structure are common auxiliary structures. The silicon supplement structure can be used to supplement silicon in the middle and late stages of crystal growth to adjust the balance and supersaturation of the carbon-silicon components. The temperature control structure can adjust the distance between the growth surface of the crystal and the silicon carbide powder (i.e., the material-crystal distance), thereby adjusting the temperature gradient in the area where the crystal growth surface is located, making the temperature gradient as stable as possible, thereby ensuring the growth rate and quality of the crystal.

[0003] The inventors have discovered that the silicon replenishing structure and the temperature regulating structure in the prior art mostly achieve corresponding purposes through the mechanical structure at the bottom of the crucible. However, the space below the crucible is limited, and the control and coordination between different mechanical structures are prone to interference and contradiction. Therefore, the two are usually arranged one by one in the same crystal growth device. Accordingly, the existing crystal growth device cannot have both the functions of silicon replenishing and temperature regulating. Summary of the invention

[0004] The purpose of the present invention includes providing a crystal growth device and a crystal growth method having both silicon replenishment and temperature adjustment functions, which can have both silicon replenishment and temperature adjustment functions and effectively ensure the growth rate and quality of silicon carbide crystals.

[0005] The embodiments of the present invention can be implemented as follows:

[0006] In a first aspect, the present invention provides a crystal growth device having both silicon replenishment and temperature adjustment functions, comprising:

[0007] A crucible, the crucible comprising a crucible cover and a crucible body, wherein the crucible cover is openably and closably arranged on the top of the crucible body;

[0008] A seed crystal, the seed crystal is arranged on the inner wall of the crucible cover and is used to grow silicon carbide crystals;

[0009] A lifting partition, the lifting partition is lifted and lowered in the crucible, a plurality of through holes are provided on the lifting partition, and the upper surface of the lifting partition is used to carry silicon carbide powder;

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

[0011] In an optional embodiment, a guide column is provided at the center of the bottom wall of the crucible body, the guide column and the bottom wall of the crucible body are perpendicular to each other, and a guide hole is provided at the center of the lifting partition, and the guide hole is slidably matched with the guide column.

[0012] In an optional embodiment, a first planar portion is provided on a peripheral wall of the guide column, and a second planar portion is provided on an inner wall of the guide hole, and the second planar portion is slidably matched with the first planar portion.

[0013] In an optional embodiment, the peripheral wall of the lifting partition is slidably matched with the inner surface of the peripheral wall of the crucible body.

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

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

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

[0017] In an optional embodiment, the inner wall of the crucible body is provided with a flow guide cover, the internal channel of the flow guide cover includes a cylindrical section and a conical section 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 optional embodiment, the air guide 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 replenishment and temperature adjustment functions described in any one of the aforementioned embodiments, comprising:

[0020] Filling the solid tantalum silicide into the bottom of the crucible body;

[0021] The lifting partition is placed in the crucible body in a liftable manner and supported on the solid tantalum silicide;

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

[0023] The crucible is covered with a lid having the seed crystal, and the crucible is heated.

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

[0025] The crystal growth device and method are provided with a lifting baffle inside the crucible body, and solid tantalum silicide is loaded between the bottom wall of the crucible body and the lifting baffle, and silicon carbide powder is loaded above the lifting baffle. During the crystal growth process, the solid tantalum silicide can be gradually melted into liquid tantalum silicide. Under the gravity extrusion of the silicon carbide powder and the lifting baffle, the liquid tantalum silicide will flow through the multiple through holes on the lifting baffle to the upper surface of the lifting baffle and contact with the silicon carbide powder, thereby reacting with the excess carbon component to generate a tantalum silicon carbon ternary compound, so as to achieve automatic silicon replenishment while fixing the excess carbon component, and ensure the balance and supersaturation of the silicon component and the carbon component as much as possible. At the same time, the lifting baffle 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, so as to compensate for the material-crystal distance lost 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 have both the functions of silicon replenishment and temperature adjustment, 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 drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the structure of the crystal growth device with both silicon replenishment and temperature adjustment functions provided in this embodiment before the tantalum silicide is melted;

[0028] Figure 2 A top view of a lifting partition provided in an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of the structure of the crystal growth device with both silicon replenishment and temperature adjustment functions provided in this embodiment after the tantalum silicide is melted.

[0030] icon:

[0031] 100 - crucible; 110 - crucible body; 120 - crucible cover; 122 - seed crystal; 124 - silicon carbide crystal; 200 - lifting baffle; 210 - through hole; 220 - guide hole; 222 - second plane portion; 300 - tantalum silicide; 400 - guide column; 410 - first plane portion; 500 - flow guide cover; 510 - cylindrical section; 520 - conical section; 600 - silicon carbide powder. DETAILED DESCRIPTION

[0032] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here 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 accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0035] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, if the terms "first", "second", etc. appear, they are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0036] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention may be combined with each other.

[0037] In the prior art, the silicon carbide crystal growth device based on the PVT method usually needs to be provided with a silicon supplement structure and a temperature adjustment structure. Among them, the silicon supplement structure is used to supplement the silicon component into the crucible in the middle and late stages of crystal growth, thereby making up for the deficiency of the silicon component in the middle and late stages of crystal growth, maintaining the balance of the carbon component and the silicon component as much as possible, and ensuring the growth rate and quality of the silicon carbide crystal. The temperature adjustment structure is used to adjust the temperature gradient in the area where the growth surface of the silicon carbide crystal is located, so that it remains unchanged as much as possible, thereby ensuring the growth rate and quality of the silicon carbide crystal. Because as the silicon carbide crystal grows, its growth surface is constantly lowered, and the distance from the silicon carbide powder is bound to continue to decrease, resulting in the temperature gradient in the area where the growth surface of the silicon carbide crystal is located constantly changing, and the temperature adjustment structure can adjust the distance between the growth surface of the silicon carbide crystal and the silicon carbide powder (i.e., the material-crystal distance) to make it as unchanged as possible, thereby maintaining the stability of the temperature gradient in the area 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] The crucible body 110 and the crucible cover 120 of this embodiment can both be made of graphite, and a tantalum carbide coating (not shown) is provided on the inner wall of the crucible body 110. The purpose of providing 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 silicon carbide powder 600 and the growth rate of silicon carbide crystal 124, in this embodiment, a flow guide 500 is provided on the inner side of the peripheral wall of the crucible body 110. The internal channel of the flow guide 500 includes a cylindrical section 510 and a conical section 520 which are connected in sequence from top to bottom. The cylindrical section 510 is used to accommodate the seed crystal 122. The diameter of the conical section 520 gradually increases from top to bottom, so that the gas phase crystal growth component formed by the sublimation of the silicon carbide powder 600 can be guided to flow to the seed crystal 122, and the growth shape of the silicon carbide crystal 124 can also be limited. Furthermore, the flow guide 500 is made of tantalum carbide to improve its corrosion resistance and extend its service life.

[0044] Please refer to Figure 2 , 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 lifted and lowered in 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 and the guide post 400 are slidably matched, and the peripheral wall of the lifting partition 200 and the inner surface of the peripheral wall of the crucible body 110 are slidably matched, so that the lifting partition 200 can be kept as horizontal as possible during the lifting process, so as to ensure that the height of the silicon carbide powder 600 on the lifting partition 200 at different positions is as equal as possible, and then ensure that the distance between the silicon carbide powder 600 and the growth surface of the silicon carbide crystal 124 at different positions (i.e., the material-crystal distance at different positions) is as equal as possible, so as to make the temperature gradient of each position in the region where the growth surface of the silicon carbide crystal 124 is located as equal as possible, so as to ensure that the growth rate of each position of the silicon carbide crystal 124 is 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, the peripheral wall of the guide column 400 is provided with a first plane portion 410, and the inner wall of the guide hole 220 is provided with a second plane portion 222, and the second plane portion 222 is slidably matched with the first plane portion 410. In this way, the reliability and guiding performance of the sliding match between the guide column 400 and the guide hole 220 can be further improved, so that the lifting partition 200 can be stably lifted and lowered while maintaining horizontality.

[0046] It should be noted that, in other embodiments, the lifting partition 200 may also achieve stability during the lifting process only by the sliding cooperation between its peripheral wall and the inner surface of the peripheral wall of the crucible body 110, without providing the guide column 400 and the guide hole 220; or, the lifting partition 200 may also achieve stability during the lifting process only by the guide column 400 and the guide hole 220, and the peripheral wall thereof may not be in contact with the inner surface of the peripheral wall of the crucible body 110 but may have a certain distance therebetween.

[0047] The multiple through holes 210 on the lifting baffle 200 can be arranged as needed. In the present embodiment, the multiple through holes 210 are arranged at intervals along the circumference and radial direction of the lifting baffle 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 baffle 200, thereby improving the efficiency of silicon replenishment.

[0048] In addition, the aperture of the through hole 210 gradually increases from the center to the edge of the lifting baffle 200. That is, the closer to the edge of the lifting baffle 200, the larger the aperture of the through hole 210 (but not larger than the particle size of the silicon carbide powder itself, so as to prevent the silicon carbide powder from falling in). Such an arrangement can make the silicon replenishment efficiency at the edge of the lifting baffle 200 higher than that at the center, which can make up for the problem that the edge is more lacking in silicon components than the center because the sublimation efficiency of the silicon carbide powder 600 at the edge is faster than that at the center.

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

[0050] During the crystal growth process, the solid tantalum silicide 300 can be gradually melted into 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 with the silicon carbide powder 600 (see Figure 3 ), thereby reacting with the excess carbon component to form a tantalum-silicon-carbon ternary compound, so as to achieve automatic silicon replenishment while fixing the excess carbon component, and to ensure the balance and supersaturation of the silicon component and the carbon component as much as possible. At the same time, the lifting baffle 200 and the silicon carbide powder 600 thereon will gradually descend, thereby gradually increasing the distance between the silicon carbide powder 600 and the growth surface of the crystal, so as to make up for the material-crystal distance lost due to the continuous descent of the growth surface of the crystal, and to ensure that the temperature gradient of the area where the growth surface of the crystal is located is as stable as possible. That is, the crystal growth device and method have both the functions of silicon replenishment and temperature adjustment, which 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 baffle 200, and the filling height of the silicon carbide powder 600 affects the growth thickness of the crystal (i.e., the loss of the material crystal distance). The descending height of the lifting baffle 200 should be consistent with the growth thickness of the crystal as much as possible, so that the material crystal distance can be kept constant as much as possible, and the temperature gradient in the area where the growth surface of the crystal is located can be ensured to be continuous and stable. 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 in the aforementioned crystal growth device with both silicon replenishment and temperature adjustment functions. The crystal growth method comprises the following steps:

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

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

[0055] Step S300 : loading the silicon carbide powder 600 onto the upper surface of the lifting partition 200 .

[0056] Step S400 : Covering the crucible 100 with the seed crystal 122 is performed, and heating the crucible 100 .

[0057] By adopting the above-mentioned crystal growth method, the automatic replenishment of the silicon component of the silicon carbide crystal 124 during the growth process and the temperature regulation of the crystal growth surface can be achieved simultaneously, that is, it has both silicon replenishment and temperature regulation functions.

[0058] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a technician familiar with the technical field 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 replenishment and temperature adjustment functions, characterized in that: include: A crucible (100), the crucible (100) comprising a crucible cover (120) and a crucible body (110), the crucible cover (120) being openably and closably disposed on the top of the crucible body (110); A seed crystal (122), the seed crystal (122) being arranged on the inner wall of the crucible cover (120) and used for growing a silicon carbide crystal (124); A lifting partition (200), the lifting partition (200) being arranged in the crucible body (110) in a liftable manner, the lifting partition (200) being provided with a plurality of through holes (210), and the upper surface of the lifting partition (200) being 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 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 the multiple through holes (210).

2. The crystal growth device with both silicon replenishment and temperature adjustment functions according to claim 1, characterized in that: A guide column (400) is arranged at the center of the bottom wall of the crucible body (110), and the guide column (400) and the bottom wall of the crucible body (110) are perpendicular to each other. A guide hole (220) is arranged at the center of the lifting partition (200), and the guide hole (220) is slidably matched with the guide column (400).

3. The crystal growth device with both silicon replenishment and temperature adjustment functions according to claim 2, characterized in that: The peripheral wall of the guide column (400) is provided with a first plane portion (410), and the inner wall of the guide hole (220) is provided with a second plane portion (222), and the second plane portion (222) is slidably matched with the first plane portion (410).

4. The crystal growth device with both silicon replenishment and temperature adjustment functions according to claim 1, characterized in that: The peripheral wall of the lifting partition (200) is slidably matched with the inner surface of the peripheral wall of the crucible body (110).

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

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

7. The crystal growth device with both silicon replenishment and temperature adjustment functions according to claim 1, characterized in that: The crucible body (110) and the crucible cover (120) are both made of graphite, and a tantalum carbide coating is provided on the inner wall of the crucible body (110).

8. The crystal growth device with both silicon replenishment and temperature adjustment functions according to claim 1, characterized in that: A flow guide cover (500) is arranged on the inner wall of the crucible body (110), and the internal channel of the flow guide cover (500) comprises a cylindrical section (510) and a conical section (520) which 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.

9. The crystal growth device with both silicon replenishment and temperature adjustment functions according to claim 8, characterized in that: The deflector cover (500) is made of tantalum carbide.

10. A crystal growth method, based on the crystal growth device with both silicon replenishment and temperature adjustment functions as claimed in any one of claims 1 to 9, characterized in that: include: Filling the solid tantalum silicide (300) into the bottom of the crucible body (110); The lifting partition (200) is placed inside the crucible body (110) in a liftable manner and supported on the solid tantalum silicide (300); The silicon carbide powder (600) is loaded onto the upper surface of the lifting partition (200); The crucible (100) is heated by covering the crucible with a crucible cover (120) on which the seed crystal (122) is disposed.

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