Seed crystal for supplementary doping and crystal growth equipment
By processing a recess on the seed crystal to place the dopant, the problem of requiring additional equipment and manual operation for secondary doping in the prior art is solved, thus saving time and cost.
Patent Information
- Application Number
- CN202423243512.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-12-27
AI Technical Summary
In the existing technology, when pulling N-type single crystal silicon rods, the secondary doping of antimony requires additional equipment and manual operation, which increases time and cost.
A recess is machined on the seed crystal to place the dopant. The dopant enters the molten silicon along with the seed crystal to complete the secondary doping operation, avoiding the need for additional doping equipment.
It saves time and cost during secondary addition and simplifies the operation process.
Smart Images
Figure CN223548159U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of crystal growth technology, and in particular to a seed crystal for supplementary doping and a crystal growth device. Background Technology
[0002] In related technologies, when pulling N-type single-crystal silicon rods, antimony, a highly volatile element, is added to the silicon material to reduce the resistivity difference between the head and tail of the rod. However, during the crystal pulling process, issues such as unqualified crystal pulling, shoulder breakage, and equal-diameter breakage occur, requiring a second crystal pulling without adding more material. At this point, due to the high volatility of antimony, the doping concentration in the silicon melt has changed. If production continues, the crystal rod will not reach the set target value, leading to a decrease in the crystal rod qualification rate. A second doping is required. The second doping uses a doping device to add the doping element to the silicon melt, but this requires additional equipment and personnel to operate, which is time-consuming and labor-intensive. Utility Model Content
[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, one objective of the present invention is to provide a seed crystal for secondary doping, wherein a recess is processed on the seed crystal for placing the dopant. The dopant enters the molten silicon along with the seed crystal to complete the secondary doping operation without the need for additional doping devices, thereby saving time and cost during the secondary doping process.
[0004] This invention also proposes a crystal growth device having the above-mentioned seed crystals for supplementary doping.
[0005] According to a first aspect of the present invention, a seed crystal for supplementing doping includes: a seed crystal body, the seed crystal body being a column extending along a first direction, the two ends of the seed crystal body along the first direction being a first end and a second end, the first end having a recessed portion, the recessed portion being located on the circumferential sidewall of the seed crystal body, the recessed portion being recessed toward the center of the seed crystal body, and the recessed portion being used to place a dopant.
[0006] According to the present invention, a seed crystal for secondary doping is provided, and a recess is formed on the seed crystal. The recess is used to place the dopant. The dopant enters the silicon melt with the seed crystal to complete the secondary doping operation. No additional doping device is required, thereby saving time and cost during the secondary doping process.
[0007] According to some embodiments of the present invention, the seed crystal body is a cylinder, the recessed portion includes at least one groove, and a plurality of the grooves are arranged at intervals along the circumference of the seed crystal body.
[0008] According to some embodiments of the present invention, in the first direction, the sidewall of the groove facing the first end is a first sidewall, and the first sidewalls of the plurality of grooves are all coplanar.
[0009] According to some embodiments of the present invention, the recess includes an annular groove, which is an annular groove body surrounding the seed crystal body.
[0010] According to some embodiments of the present invention, in the first direction, the recessed portion has a first sidewall in the direction toward the first end, and in the direction from the center of the seed crystal body to the circumferential sidewall of the seed crystal body, the first sidewall is inclined toward the second end.
[0011] According to some embodiments of the present invention, in the first direction, at least a portion of the first sidewall is recessed toward the first end to form an arcuate surface.
[0012] According to some embodiments of the present invention, the recessed portion further has a bottom wall disposed opposite to the opening of the recessed portion, and the included angle between the first side wall and the bottom wall is A, satisfying: 15°≤A≤60°.
[0013] According to some embodiments of the present invention, in the first direction, the size of the first sidewall is B, satisfying: 2mm≤B≤5mm; and / or, in the first direction, the size of the opening of the recess is C, satisfying: 8mm≤C≤25mm; and / or, in the direction from the center of the seed crystal body to the circumferential sidewall of the seed crystal body, the depth of the recess is D, satisfying: 5mm≤D≤10mm.
[0014] According to some embodiments of the present invention, the end face of the first end that is away from the second end is the first end face, and in the first direction, the distance between the first sidewall and the first end face is E, which satisfies: 20mm≤E≤50mm.
[0015] A crystal growth apparatus according to a second aspect of the present invention includes: a seed crystal for supplementary doping as described in the first aspect of the present invention.
[0016] According to the crystal growth equipment of this utility model embodiment, by setting the above-mentioned seed crystal for supplementary doping, the dopant enters the silicon liquid along with the seed crystal to complete the secondary doping operation, without the need to add an additional doping device, thereby saving time and cost during the secondary doping.
[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0018] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0019] Figure 1 This is a schematic diagram of a seed crystal for supplementary doping according to some embodiments of the present invention;
[0020] Figure 2 yes Figure 1 A cross-sectional view of the seed crystal used for supplementary doping;
[0021] Figure 3 This is a schematic diagram of a seed crystal for supplementary doping according to other embodiments of the present invention;
[0022] Figure 4 yes Figure 3 A cross-sectional view of the seed crystal used for supplementary doping;
[0023] Figure 5 yes Figure 3 A cross-sectional view of the seed crystal used for doping, with the relevant dimensions marked in the accompanying drawing.
[0024] Figure label:
[0025] 100. Seed crystal;
[0026] 10. Seed crystal body; 11. First end; 12. Second end; 13. Circumferential sidewall;
[0027] 20. Recessed portion; 21. Groove; 22. Annular groove; 23. First sidewall; 24. Bottom wall. Detailed Implementation
[0028] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0029] In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0031] The following is for reference. Figures 1-5 Description of a seed crystal 100 for supplemental doping according to an embodiment of the present invention.
[0032] According to a first aspect embodiment of the present invention, a seed crystal 100 for supplementary doping includes a seed crystal body 10, the seed crystal body 10 being oriented along a first direction (see attached figure). Figure 2 The seed crystal body 10 extends in the X direction. The two ends of the seed crystal body 10 along the first direction are the first end 11 and the second end 12, respectively. When the seed crystal 100 is fixed in the crystal growth device for crystal pulling, the first direction is the up and down direction. The first end 11 is the lower end of the seed crystal body 10, and the second end 12 is the upper end of the seed crystal body 10. The seed crystal 100 is fixed in the crystal growth device through the second end 12.
[0033] When using seed crystal 100 to obtain N-type crystal rods, phosphorus-silicon alloy needs to be added to the silicon material. However, phosphorus has a segregation coefficient of 0.35 < 1 in silicon and low volatility, resulting in a high resistivity distribution at the beginning and end of the crystal rod. To reduce this resistivity difference, antimony, a highly volatile element, is added to the silicon material. However, in actual production using seed crystal 100, issues such as unqualified crystal pulling, shoulder breakage, and equal-diameter breakage occur, requiring a second crystal pulling process without adding more material. At this point, due to the high volatility of antimony, the antimony doping concentration in the silicon melt has changed. If production continues, the crystal rods will not reach the target value, leading to a decrease in the crystal rod qualification rate. Therefore, it is necessary to replenish the antimony doping in the silicon melt. Related technologies use a doping device to add the dopant element to the silicon melt, but this requires additional equipment and manual operation, which is time-consuming and labor-intensive.
[0034] Therefore, in this application, a recess 20 is formed at the first end 11 of the seed crystal body 10. The recess 20 is located on the circumferential sidewall 13 of the seed crystal body 10, and is recessed towards the center of the seed crystal body 10. The recess 20 is used to place a dopant, for example, the dopant can be antimony. The amount of dopant added at one time can be about 8g, but less than 10g. The dopant solid is fixed in the recess 20 of the seed crystal 100, and then the seed crystal 100 is placed in the crystal growth equipment. The first end 11 of the seed crystal 100 is gently inserted into the silicon liquid. When the recess 20 contacts the silicon liquid, the dopant will enter the silicon liquid, completing the secondary doping operation. The recess 20 is directly processed on the seed crystal 100, which simplifies the processing method of the recess 20 and does not occupy the space outside the seed crystal 100. Moreover, the dopant directly enters the silicon liquid along with the seed crystal 100, without the need for additional doping devices and without the need for personnel to perform additional actions on the doping, saving time and effort.
[0035] For example, the recess 20 can be a groove 21 with a small opening and a large internal space.
[0036] When seed crystal 100 is used for the first time to generate a crystal, the dopant is injected into the crystal growth equipment along with the molten silicon. It is not necessary to inject additional dopant into the molten silicon within the crystal growth equipment. Therefore, it is not necessary to fabricate a recess 20 on seed crystal 100 at this time. When a second crystal generation is required, dopant needs to be added to the molten silicon. In this case, a recess 20 can be fabricated on the seed crystal body 10, the dopant can be placed within the recess 20, and then the first end 11 of seed crystal 100 can be inserted into the molten silicon. When the recess 20 contacts the molten silicon, the dopant will enter the molten silicon, completing the secondary doping operation.
[0037] Alternatively, during the production and processing of seed crystal 100, recesses 20 may be machined on some of the seed crystal 100, while others may not require recesses 20. During the first crystal pulling, both seed crystal 100s with and without recesses 20 can be pulled. When the seed crystal 100 is placed in the molten silicon, the second end 12 of the seed crystal 100 will dissolve into the molten silicon over time. Only during the second crystal pulling is a seed crystal 100 with recesses 20 selected, and the dopant is introduced into the molten silicon along with it.
[0038] According to the present invention, a seed crystal 100 for secondary doping is provided, and a recessed portion 20 is formed in the seed crystal 100. The recessed portion 20 is used to place the dopant. The dopant enters the silicon melt with the seed crystal 100 to complete the secondary doping operation. No additional doping device is required, thereby saving time and cost during the secondary doping.
[0039] According to some embodiments of this utility model, refer to Figures 1-2The seed crystal body 10 is cylindrical, and the recessed portion 20 includes at least one groove 21. The recessed portion 20 may include one groove 21 or multiple grooves 21. The multiple grooves 21 are arranged at intervals along the circumference of the seed crystal body 10, which simplifies the processing of the recessed portion 20. The number of grooves 21 can be determined according to the dopant content required during secondary crystal pulling. When more dopant is required, multiple grooves 21 can be processed on the seed crystal 100; when less dopant is required, one groove 21 can be processed on the seed crystal 100, which can reduce the processing time of the groove 21. Alternatively, different numbers of grooves 21 can be selected based on the dopant content required during secondary crystal pulling.
[0040] According to some embodiments of this utility model, refer to Figures 1-2 In the first direction, the sidewall of the groove 21 facing the first end 11 is the first sidewall 23. After the seed crystal 100 is placed in the crystal growth device, the first sidewall 23 is the sidewall close to the silicon liquid. The first sidewalls 23 of the multiple grooves 21 are all coplanar. By setting the multiple grooves 21 in the same plane, after the seed crystal 100 containing dopant is placed in the silicon liquid, the dopant located in different grooves 21 can simultaneously contact the silicon liquid and disperse into the silicon liquid at the same time, so that the dopant content in the silicon liquid can quickly reach the highest doping concentration.
[0041] According to some embodiments of this utility model, refer to Figures 3-4 The recessed portion 20 includes an annular groove 22, which is an annular groove surrounding the seed crystal body 10. Processing the recessed portion 20 into an annular groove surrounding the seed crystal body 10 can make the processing of the recessed portion 20 more standardized and mechanized, and make the uniformity of the recessed portion 20 processed on the seed crystal 100 better.
[0042] According to some embodiments of this utility model, refer to Figures 1-4 In the first direction, the recess 20 has a first sidewall 23 facing the first end 11. After the seed crystal 100 is placed in the crystal growth apparatus, the first sidewall 23 is the sidewall close to the molten silicon. When the recess 20 includes at least one groove 21, the first sidewall 23 is the sidewall of the groove 21 facing the first end 11; when the recess 20 includes an annular groove 22, the first sidewall 23 is the sidewall of the annular groove 22 facing the first end 11.
[0043] In the direction from the center of the seed crystal body 10 to the circumferential sidewall 13 of the seed crystal body 10, the first sidewall 23 is inclined toward the second end 12. After the seed crystal 100 is placed in the crystal growth device, the first sidewall 23 is inclined upward. After the dopant is placed in the recess 20, since the first sidewall 23 is inclined upward, the first sidewall 23 can prevent the dopant from falling out of the recess 20, and can prevent the dopant from falling out of the recess 20 when the seed crystal 100 is transferred.
[0044] According to some embodiments of this utility model, refer to Figure 1 , Figure 3 In the first direction, at least a portion of the first sidewall 23 is recessed toward the first end 11 to form an arcuate surface. This recess can be a part of the first sidewall 23 or the entire first sidewall 23. Recessing the first sidewall 23 toward the first end 11 allows the recessed portion 20 to have a deeper accommodating space, enabling it to accommodate more dopants. Furthermore, recessing the first sidewall 23 toward the first end 11 allows it to better block dopants located within the recessed portion 20.
[0045] According to some embodiments of this utility model, refer to Figures 1-5 The recessed portion 20 also has a bottom wall 24, which is disposed opposite to the opening of the recessed portion 20. The bottom wall 24 is also connected to the side of the first side wall 23 facing the seed crystal body 10. The included angle between the first side wall 23 and the bottom wall 24 is A, which satisfies: 15°≤A≤60°. By limiting the tilt angle of the first side wall 23, sufficient space can be provided between the first side wall 23 and the bottom wall 24 to accommodate the dopant, avoiding the first side wall 23 from having too large a tilt angle and thus failing to effectively block the dopant; it also avoids the first side wall 23 from having too small a tilt angle, thus making the space formed between the first side wall 23 and the bottom wall 24 too small to accommodate a sufficient amount of dopant.
[0046] For example, the included angle between the first sidewall 23 and the bottom wall 24 can be 15°, 30°, 45° or 60°, with 45° being the preferred angle.
[0047] According to some embodiments of this utility model, refer to Figure 5 In the first direction, the dimension of the first sidewall 23 is B, which satisfies: 2mm≤B≤5mm, that is, the height of the first sidewall 23 is between 2mm and 5mm, which allows a suitable accommodating space to be formed between the first sidewall 23 and the bottom wall 24, and the first sidewall 23 can also better block dopants. For example, the dimension of the first sidewall 23 can be 2mm, 3mm, 4mm or 5mm, etc.
[0048] In the first direction, the opening size of the recess 20 is C, satisfying: 8mm ≤ C ≤ 25mm, that is, the height of the opening of the recess 20 is between 8mm and 25mm. When the dopant is placed into the recess 20 through the opening, there is sufficient space for the dopant to be placed within the recess 20, thus facilitating the placement of the dopant and preventing it from touching the circumferential sidewall 13 of the seed crystal body 10 during placement, which could cause the dopant to fall off. For example, the opening size of the recess 20 can be 8mm, 15mm, 20mm, or 25mm, etc.
[0049] In the direction from the center of the seed crystal body 10 to the circumferential sidewall 13 of the seed crystal body 10, the depth of the recess 20 is D, satisfying: 5mm ≤ D ≤ 10mm. This allows for a suitable accommodating space between the first sidewall 23 and the bottom wall 24, accommodating a sufficient amount of dopant. For example, if the seed crystal body 10 is a cylinder with a radius between 15mm and 25mm, limiting the depth of the recess 20 to 5mm to 10mm ensures that it does not penetrate the radial direction of the seed crystal body 10 while maintaining sufficient space for the recess 20. For example, the depth of the recess 20 can be 5mm, 7mm, 9mm, or 10mm, etc.
[0050] According to some embodiments of this utility model, refer to Figure 5 The end face of the first end 11 facing away from the second end 12 is called the first end face. In the first direction, the distance between the first sidewall 23 and the first end face is E, which satisfies: 20mm≤E≤50mm. This ensures that there is a certain distance between the first sidewall 23 and the first end face, preventing the recess 20 from penetrating the first end face when it is machined on the seed crystal 100. For example, the distance between the first sidewall 23 and the first end face can be 20mm, 30mm, 40mm, or 50mm, etc.
[0051] A crystal growth apparatus according to a second aspect of the present invention includes: a seed crystal 100 for supplementary doping as described in the first aspect of the present invention.
[0052] According to the crystal growth equipment of this utility model embodiment, by setting the above-mentioned seed crystal 100 for supplementary doping, the dopant enters the silicon liquid with the seed crystal 100 to complete the secondary doping operation, without the need to add an additional doping device, thereby saving time and cost during the secondary doping.
[0053] In the description of this specification, references to terms such as "some embodiments," "optionally," "furthermore," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0054] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A seed crystal for supplementary doping, characterized in that, include: The seed crystal body is a column extending along a first direction. The two ends of the seed crystal body along the first direction are a first end and a second end, respectively. A recess is formed at the first end. The recess is located on the circumferential sidewall of the seed crystal body and is recessed toward the center of the seed crystal body. The recess is used to place a dopant.
2. The seed crystal for supplementary doping according to claim 1, characterized in that, The seed crystal body is a cylinder, and the recessed portion includes at least one groove, with multiple grooves arranged at intervals along the circumference of the seed crystal body.
3. The seed crystal for supplementary doping according to claim 2, characterized in that, In the first direction, the sidewall of the groove facing the first end is the first sidewall, and the first sidewalls of the plurality of grooves are all coplanar.
4. The seed crystal for supplementary doping according to claim 1, characterized in that, The recess includes an annular groove, which is an annular groove body surrounding the seed crystal body.
5. The seed crystal for supplementary doping according to any one of claims 1-4, characterized in that, In the first direction, the recessed portion has a first sidewall in the direction toward the first end, and in the direction from the center of the seed crystal body to the circumferential sidewall of the seed crystal body, the first sidewall is inclined toward the second end.
6. The seed crystal for supplementary doping according to claim 5, characterized in that, In the first direction, at least a portion of the first sidewall is recessed toward the first end to form an arcuate surface.
7. The seed crystal for supplementary doping according to claim 5, characterized in that, The recessed portion also has a bottom wall disposed opposite to the opening of the recessed portion, and the included angle between the first side wall and the bottom wall is A, satisfying: 15°≤A≤60°.
8. The seed crystal for supplementary doping according to claim 5, characterized in that, In the first direction, the dimension of the first sidewall is B, satisfying: 2mm≤B≤5mm; and / or, in the first direction, the dimension of the opening of the recess is C, satisfying: 8mm≤C≤25mm; and / or, in the direction from the center of the seed crystal body to the circumferential sidewall of the seed crystal body, the depth of the recess is D, satisfying: 5mm≤D≤10mm.
9. The seed crystal for supplementary doping according to claim 5, characterized in that, The end face of the first end that is away from the second end is called the first end face. In the first direction, the distance between the first sidewall and the first end face is E, which satisfies: 20mm≤E≤50mm.
10. A crystal growth apparatus, characterized in that, include: Seed crystals for supplementary doping according to any one of claims 1-9.