Preparation device and preparation method for heavy antimony doped monocrystalline silicon

Abstract

The invention discloses a preparation device and a preparation method for heavy antimony doped monocrystalline silicon. The preparation device comprises a crystal pulling furnace main body, a lifting mechanism and a first driving mechanism, a first cavity is formed in the crystal pulling furnace main body, a crucible is arranged in the first cavity, the first driving mechanism can drive the crucible to rotate, a second driving mechanism located above the crucible is arranged at the lifting end of the lifting mechanism, and the second driving mechanism can drive the crucible to rotate. The second driving mechanism can drive the seed crystal to rotate; the preparation method comprises the following steps: placing a crucible in a first chamber, and filling the crucible with a solid monocrystalline silicon material; heating the crucible to melt the solid monocrystalline silicon material in the crucible; inserting the lower end of the seed crystal into the molten monocrystalline silicon material; driving the crucible to rotate, and driving the seed crystal to rotate; wherein the rotation direction of the crucible is opposite to that of the seed crystal; the seed crystal is driven to synchronously move upwards. The method is applied to the technical field of monocrystalline silicon preparation.

Description

Technical Field

[0001] This invention relates to the technical field of single-crystal silicon preparation, and particularly to an apparatus and method for preparing heavily antimony-doped single-crystal silicon. Background Technology

[0002] Silicon is the most common and widely used semiconductor material. When molten elemental silicon solidifies, silicon atoms arrange themselves into crystal nuclei in a diamond lattice. These nuclei grow into grains with the same crystal orientation, forming monocrystalline silicon. As a relatively reactive non-metallic element crystal, monocrystalline silicon is an important component of crystal materials and is at the forefront of new material development. The manufacturing process of monocrystalline silicon involves the following steps: quartz sand - metallurgical grade silicon - purification and refining - deposition of polycrystalline silicon ingots - monocrystalline silicon - silicon wafer cutting. Its main uses are as a semiconductor material and for solar photovoltaic power generation and heating.

[0003] During the implementation process, the following problems were found with existing technologies: 1. In the existing process of preparing monocrystalline silicon, it is impossible to rotate the crucible and seed crystal. Most of them are grown by stretching monocrystalline silicon using the Czochralski method. This results in an uneven temperature gradient at the solid-liquid interface of monocrystalline silicon and poor stability. As a result, monocrystalline silicon is prone to breakage during the preparation and production process, and the radial uniformity of the electrical properties of monocrystalline silicon cannot be guaranteed. 2. Currently, when using a crystal pulling furnace to prepare monocrystalline silicon, it is necessary to place solid polycrystalline silicon material in a crucible and heat the crucible to melt the polycrystalline silicon material. During the heating process, the heat inside the crucible will diffuse towards the furnace wall, resulting in a rapid temperature drop inside the crucible, which affects the crystallization quality of monocrystalline silicon. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art. The primary objective is to provide an apparatus for preparing heavy antimony-doped single crystal silicon that can avoid silicon blasting and reduce heat diffusion. The second objective is to provide a method for preparing heavily antimony-doped monocrystalline silicon that can avoid the breakage of monocrystalline silicon.

[0005] The technical solution adopted in this invention is as follows: the preparation device includes a crystal pulling furnace body, a lifting mechanism and a first driving mechanism. The crystal pulling furnace body is provided with a first chamber, and a crucible is provided in the first chamber. The first driving mechanism can drive the crucible to rotate. The lifting end of the lifting mechanism is provided with a second driving mechanism located above the crucible. The second driving mechanism can drive the seed crystal to rotate.

[0006] Furthermore, the inner wall of the first chamber is provided with a heat insulation layer, which surrounds the outside of the crucible. The crystal pulling furnace body is provided with a second chamber, which is provided with high-temperature heat insulation cotton, which surrounds the outside of the heat insulation layer.

[0007] Furthermore, the insulation layer and the high-temperature insulation cotton are symmetrically arranged in the first chamber.

[0008] Furthermore, the bottom of the first cavity is provided with an installation groove, the drive end of the first drive mechanism is provided with a connecting shaft, the connecting shaft is located in the installation groove, the upper end of the connecting shaft is connected to an installation seat, the installation seat is provided with a crucible placement groove, the crucible is located on the crucible placement groove, a heating tube is sleeved on the outside of the crucible, a heater is provided on the main body of the crystal pulling furnace, and the heater is electrically connected to the heating tube.

[0009] Furthermore, the inner wall of the mounting groove is provided with an annular limiting groove, and the mounting base is provided with an annular limiting block, which slides in the annular limiting groove.

[0010] Furthermore, the upper end of the crystal pulling furnace body is provided with a furnace cover, and the furnace cover is provided with a secondary chamber, an argon filling tube and a vacuum pump, all of which are connected to the first chamber. The secondary chamber is provided with a third chamber that is connected to the first chamber, and the lifting mechanism and the second driving mechanism are both located in the third chamber.

[0011] Furthermore, the lifting mechanism includes a multi-stage telescopic rod, the upper end of which is fixedly connected to the upper end of the third chamber. The second driving mechanism includes a drive motor, which is located at the lower end of the multi-stage telescopic rod. The drive end of the drive motor is provided with a movable seat, and a rotating shaft is provided on the movable seat. The seed crystal is located at the lower end of the rotating shaft.

[0012] Furthermore, a guide block is provided on the movable seat, and a guide groove is provided in the third chamber, with the guide block slidably engaged in the guide groove.

[0013] Furthermore, an annular overflow plate is fitted onto the crucible, the annular overflow plate abuts against the inner wall of the first chamber, and an overflow groove is provided at the upper end of the annular overflow plate.

[0014] Furthermore, the present invention also provides a method for preparing heavy antimony-doped single-crystal silicon, which employs the aforementioned apparatus for preparing heavy antimony-doped single-crystal silicon, and includes the following steps: Step S101: Place the crucible in the first chamber and fill the crucible with solid single-crystal silicon material; Step S102: Heat the crucible to melt the solid single-crystal silicon material in the crucible; Step S1003: Insert the lower end of the seed crystal into the molten monocrystalline silicon material; Step S104: Drive the crucible to rotate and drive the seed crystal to rotate; wherein the rotation direction of the crucible is opposite to the rotation direction of the seed crystal. Step S105: Drive the seed crystal to move upward synchronously.

[0015] The beneficial effects of this invention are: In contrast to the shortcomings of existing technologies, this invention, through the arrangement of a lifting mechanism, a first driving mechanism, and a second driving mechanism, allows the crucible to rotate when stretching monocrystalline silicon is required. Furthermore, the seed crystal also rotates and moves upwards synchronously during the stretching process. This dual rotational coordination ensures the uniformity and stability of the temperature gradient at the solid-liquid interface during the stretching growth of monocrystalline silicon, preventing brittle fracture during growth and ensuring consistent radial uniformity of the electrical properties. This gives the fabrication device the advantage of preventing brittle fracture. The inclusion of a heat insulation layer and high-temperature insulation cotton effectively reduces heat diffusion towards the furnace wall during use, thereby slowing the rate of temperature drop within the crucible. This helps maintain the crucible temperature, reduces energy consumption, and to a certain extent maintains the crystal quality of the monocrystalline silicon, meeting the requirements of the fabrication device and thus enabling it to prevent brittle fracture. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a cross-sectional structural schematic diagram of the present invention; Figure 3 yes Figure 2 A magnified view of part B; Figure 4 yes Figure 2 A magnified view of part A.

[0018] The attached figures are labeled as follows: 1. Crystal pulling furnace body; 2. Lifting mechanism; 3. First drive mechanism; 4. First chamber; 5. Crucible; 6. Second drive mechanism; 7. Seed crystal; 8. Insulation layer; 9. Second chamber; 10. High-temperature insulation cotton; 11. Mounting groove; 12. Connecting shaft; 13. Mounting base; 14. Crucible placement groove; 15. Heating tube; 16. Heater; 17. Annular limiting groove; 18. Annular limiting block; 19. Furnace cover; 20. Secondary chamber; 21. Argon filling tube; 22. Vacuum extractor; 23. Third chamber; 24. Multi-stage telescopic rod; 25. Drive motor; 26. Moving base; 27. Rotating shaft; 28. Guide block; 29. ​​Guide groove; 30. Annular overflow plate; 31. Overflow groove.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, clockwise, counterclockwise, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0022] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0023] like Figure 1 and Figure 2As shown, in this embodiment, the preparation apparatus includes a crystal pulling furnace body 1, a lifting mechanism 2, and a first driving mechanism 3. The crystal pulling furnace body 1 is provided with a first chamber 4, and a crucible 5 is provided in the first chamber 4. The first driving mechanism 3 can drive the crucible 5 to rotate. The lifting end of the lifting mechanism 2 is provided with a second driving mechanism 6 located above the crucible 5. The second driving mechanism 6 can drive the seed crystal 7 to rotate.

[0024] It should be noted that the lifting mechanism 2 can drive the seed crystal 7 to move up and down, so that the seed crystal 7 can be inserted into the molten single crystal silicon material in the crucible 5 during the stretching growth operation of single crystal silicon; the first driving mechanism 3 and the second driving mechanism 6 can respectively drive the crucible 5 and the seed crystal 7 to rotate during the stretching growth operation.

[0025] In contrast to the shortcomings of existing technologies, this invention, through the arrangement of lifting mechanism 2, first driving mechanism 3 and second driving mechanism 6, enables crucible 5 to rotate when stretching growth of monocrystalline silicon is required, and seed crystal 7 can also rotate and move upward synchronously during the stretching process. This dual rotation coordination can maintain the uniformity and stability of the temperature gradient at the solid-liquid interface of monocrystalline silicon during the stretching growth process, avoiding the occurrence of bud breakage during the growth of monocrystalline silicon, thereby ensuring the radial uniformity of the electrical properties of monocrystalline silicon. This gives the fabrication device the advantage of avoiding bud breakage of monocrystalline silicon.

[0026] like Figure 2 As shown, in some embodiments, the inner wall of the first chamber 4 is provided with a heat insulation layer 8, which surrounds the outside of the crucible 5. The crystal pulling furnace body 1 is provided with a second chamber 9, and the second chamber 9 is provided with high-temperature insulation cotton 10, which surrounds the outside of the heat insulation layer 8. The heat insulation layer 8 and the high-temperature insulation cotton 10 are symmetrically arranged in the first chamber 4. The heat insulation layer 8 can be made of graphite or carbon fiber composite material, and the high-temperature insulation cotton 10 can be alumina fiber cotton or ceramic fiber cotton. Specifically, by providing the heat insulation layer 8 and the high-temperature insulation cotton 10, the diffusion of heat towards the furnace wall of the crystal pulling furnace body 1 can be effectively reduced during use of the crucible 5, thereby reducing the rate of temperature drop inside the crucible 5. This helps maintain the temperature of the crucible 5, reduces energy consumption, and to a certain extent maintains the crystallization quality of single-crystal silicon, thus meeting the requirements of the preparation apparatus.

[0027] like Figure 2 and Figure 3As shown, in some embodiments, a mounting groove 11 is provided at the bottom of the first cavity, and a connecting shaft 12 is provided at the driving end of the first driving mechanism 3. The connecting shaft 12 is located in the mounting groove 11, and a mounting base 13 is connected to the upper end of the connecting shaft 12. A crucible placement groove 14 is provided on the mounting base 13, and the crucible 5 is located on the crucible placement groove 14. A heating tube 15 is sleeved on the outside of the crucible 5, and a heater 16 is provided on the crystal pulling furnace body 1. The heater 16 is electrically connected to the heating tube 15. Specifically, the internal dimensions of the crucible placement groove 14 and the external dimensions of the crucible 5 are adapted to prevent the crucible 5 from tilting during use, thereby increasing the safety and stability of the crucible 5 during use. Secondly, the heating tube 15 is heated by the heater 16 to melt the polycrystalline silicon material in the crucible 5. In addition, the connecting shaft 12 and the mounting base 13 are driven to rotate by the first driving mechanism 3, which can be a servo motor, to achieve clockwise rotation of the crucible 5.

[0028] like Figure 3 As shown, in some embodiments, the inner wall of the mounting groove 11 is provided with an annular limiting groove 17, and the mounting base 13 is provided with an annular limiting block 18, which is slidably engaged in the annular limiting groove 17. Specifically, when the mounting base 13 rotates, the sliding engagement of the annular limiting block 18 in the annular limiting groove 17 increases the stability of the mounting base 13 during rotation, thereby preventing the mounting base 13 from shifting or tilting during rotation.

[0029] like Figure 2 and Figure 4 As shown, in some embodiments, the upper end of the crystal pulling furnace body 1 is provided with a furnace cover 19. The furnace cover 19 is provided with a secondary chamber 20, an argon filling pipe 21, and a vacuum pump 22, all of which are connected to the first chamber 4. A third chamber 23, which is connected to the first chamber 4, is provided in the secondary chamber 20. The lifting mechanism 2 and the second driving mechanism 6 are both located in the third chamber 23. Specifically, the vacuum pump 22 can evacuate the first chamber and then inject high-purity argon gas through the argon filling pipe 21 to prevent oxidation.

[0030] like Figure 2As shown, in some embodiments, the lifting mechanism 2 includes a multi-stage telescopic rod 24, the upper end of which is fixedly connected to the upper end of the third chamber 23. The second driving mechanism 6 includes a driving motor 25, located at the lower end of the multi-stage telescopic rod 24. A movable seat 26 is provided at the driving end of the driving motor 25, and a rotating shaft 27 is provided on the movable seat 26. The seed crystal 7 is disposed at the lower end of the rotating shaft 27. Specifically, the multi-stage telescopic rod 24 drives the second driving mechanism 6 and the seed crystal 7 to move up and down, allowing the lower end of the seed crystal 7 to be inserted into the molten single-crystal silicon material in the crucible 5. The driving motor 25 drives the rotating shaft 27 and the seed crystal 7 to rotate.

[0031] like Figure 4 As shown, in some embodiments, the movable seat 26 is provided with a guide block 28, and the third chamber 23 is provided with a guide groove 29, with the guide block 28 slidably engaged in the guide groove 29. Specifically, by slidably engaging the guide block 28 in the guide groove 29, the movable seat 26 moves in a single direction, preventing the movable seat 26 from deviating during movement, thereby significantly increasing the stability of the movable seat 26 during movement.

[0032] like Figure 2 As shown, in some embodiments, an annular overflow plate 30 is fitted onto the crucible 5, the annular overflow plate 30 abuts against the inner wall of the first chamber 4, and an overflow groove 31 is provided at the upper end of the annular overflow plate 30. Specifically, the annular overflow plate 30 collects the overflowing melt through the overflow groove 31 to avoid contamination.

[0033] During preparation, crucible 5 is first placed in crucible placement slot 14 located at the top of mounting base 13, and then solid monocrystalline silicon material is filled into crucible 5. Then, heater 16 is started to work, so that heater 16 drives heating tube 15 to heat and melt the solid monocrystalline silicon material in crucible 5, and the bottom end of seed crystal 7 is inserted into the molten monocrystalline silicon material. Under the double heat insulation effect of high temperature insulation cotton 10 filled inside crystal pulling furnace body 1 and heat insulation layer 8 attached to the inner wall of crystal pulling furnace body 1, the heat diffusion towards furnace wall of crystal pulling furnace body 1 is effectively reduced, thereby reducing the rate of temperature drop in crucible 5, which is conducive to maintaining the temperature of crucible 5, reducing energy consumption, and maintaining the crystallization quality of monocrystalline silicon to a certain extent. When stretching growth of monocrystalline silicon is required, the lifting mechanism 2, the first drive mechanism 3, and the second drive mechanism 6 are activated to work synchronously. The first drive mechanism 3, which is a servo motor, drives the mounting base 13 to rotate clockwise under the cooperation of the annular limiting block 18 and the annular limiting groove 17 through the connecting shaft 12. At this time, the mounting base 13 drives the crucible 5 to rotate synchronously. At the same time, the drive motor 25 drives the rotating shaft 27 to rotate counterclockwise. The rotating shaft 27 drives the seed crystal 7 to rotate. At this time, the extended end of the multi-stage telescopic rod 24 drives the moving seat 26 to move upward under the cooperation of the guide groove 29 and the guide block 28 through the drive motor 25. At the same time, the moving seat 26 drives the seed crystal 7 to move upward synchronously through the rotating shaft 27. The dual rotation and movement can keep the temperature gradient of the solid-liquid interface of monocrystalline silicon uniform and stable during the stretching growth process, avoiding the occurrence of bract breakage in monocrystalline silicon during growth. This ensures the radial uniformity of the electrical properties of monocrystalline silicon, thus meeting the requirements of the preparation device for heavily antimony-doped monocrystalline silicon.

[0034] Furthermore, the present invention also provides a method for preparing heavy antimony-doped single-crystal silicon, which employs the aforementioned apparatus for preparing heavy antimony-doped single-crystal silicon, and includes the following steps: Step S101: Place the crucible 5 in the first chamber 4 and fill the crucible 5 with solid single-crystal silicon material; Step S102: Heat the crucible 5 to melt the solid single-crystal silicon material in the crucible 5; Step S103: Insert the lower end of the seed crystal 7 into the molten monocrystalline silicon material; Step S104: Drive the crucible 5 to rotate and drive the seed crystal 7 to rotate; wherein, the rotation direction of the crucible 5 is opposite to the rotation direction of the seed crystal 7. Step S105: Drive the seed crystal 7 to move upward synchronously.

[0035] In contrast to the shortcomings of existing technologies, in this invention, when stretching growth of monocrystalline silicon is required, both the crucible 5 and the seed crystal 7 can rotate. This dual rotational movement allows the temperature gradient at the solid-liquid interface of the monocrystalline silicon to remain uniform and stable during the stretching growth process, preventing the monocrystalline silicon from experiencing bud breakage during growth. This ensures the radial uniformity of the electrical properties of the monocrystalline silicon, giving the preparation method the advantages of avoiding bud breakage and reducing heat diffusion.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An apparatus for preparing heavily antimony-doped single-crystal silicon, characterized in that: It includes a crystal pulling furnace body (1), a lifting mechanism (2) and a first driving mechanism (3). The crystal pulling furnace body (1) is provided with a first chamber (4) and a crucible (5) is provided in the first chamber (4). The first driving mechanism (3) can drive the crucible (5) to rotate. The lifting end of the lifting mechanism (2) is provided with a second driving mechanism (6) located above the crucible (5). The second driving mechanism (6) can drive the seed crystal (7) to rotate.

2. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 1, characterized in that: The inner wall of the first chamber (4) is provided with a heat insulation layer (8), which surrounds the outside of the crucible (5). The main body (1) of the crystal pulling furnace is provided with a second chamber (9), which is provided with high temperature insulation cotton (10), which surrounds the outside of the heat insulation layer (8).

3. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 2, characterized in that: The insulation layer (8) and the high-temperature insulation cotton (10) are symmetrically arranged in the first chamber (4).

4. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 1, characterized in that: The bottom of the first cavity is provided with an installation groove (11), and the driving end of the first driving mechanism (3) is provided with a connecting shaft (12). The connecting shaft (12) is located in the installation groove (11), and the upper end of the connecting shaft (12) is connected to an installation seat (13). The installation seat (13) is provided with a crucible placement groove (14), and the crucible (5) is located on the crucible placement groove (14). A heating tube (15) is sleeved on the outside of the crucible (5). A heater (16) is provided on the crystal pulling furnace body (1), and the heater (16) is electrically connected to the heating tube (15).

5. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 4, characterized in that: The inner wall of the mounting groove (11) is provided with an annular limiting groove (17), and the mounting base (13) is provided with an annular limiting block (18), which slides in the annular limiting groove (17).

6. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 1, characterized in that: The upper end of the crystal pulling furnace body (1) is provided with a furnace cover (19). The furnace cover (19) is provided with a secondary chamber (20), an argon filling pipe (21), and a vacuum pump (22), all of which are connected to the first chamber (4). The secondary chamber (20) is provided with a third chamber (23) that is connected to the first chamber (4). The lifting mechanism (2) and the second driving mechanism (6) are both located in the third chamber (23).

7. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 6, characterized in that: The lifting mechanism (2) includes a multi-stage telescopic rod (24), the upper end of which is fixedly connected to the upper end of the third chamber (23). The second driving mechanism (6) includes a driving motor (25), which is located at the lower end of the multi-stage telescopic rod (24). The driving end of the driving motor (25) is provided with a movable seat (26), and a rotating shaft (27) is provided on the movable seat (26). The seed crystal (7) is located at the lower end of the rotating shaft (27).

8. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 7, characterized in that: The movable seat (26) is provided with a guide block (28), and the third chamber (23) is provided with a guide groove (29). The guide block (28) is slidably fitted in the guide groove (29).

9. The apparatus for preparing heavily antimony-doped single-crystal silicon according to claim 1, characterized in that: An annular overflow plate (30) is fitted onto the crucible (5), and the annular overflow plate (30) abuts against the inner wall of the first chamber (4). An overflow groove (31) is provided at the upper end of the annular overflow plate (30).

10. A method for preparing heavily antimony-doped single-crystal silicon, characterized in that: It employs the apparatus for preparing heavily antimony-doped single-crystal silicon as described in any one of claims 1-9, and includes the following steps: Step S101: Place the crucible (5) in the first chamber (4) and fill the crucible (5) with solid single crystal silicon material; Step S102: Heat the crucible (5) to melt the solid single-crystal silicon material in the crucible (5); Step S103: Insert the lower end of the seed crystal (7) into the molten monocrystalline silicon material; Step S104: Drive the crucible (5) to rotate and drive the seed crystal (7) to rotate; wherein the rotation direction of the crucible (5) is opposite to the rotation direction of the seed crystal (7); Step S105: Drive the seed crystal (7) to move upward synchronously.

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