Single crystal manufacturing apparatus

Abstract

The present application provides a single crystal manufacturing device with a dopant supply device, which does not have the problem of component breakage or falling off, and can cope with the vertical movement of the heat shielding member. The single crystal manufacturing device (1) comprises a chamber (10), a crucible (12) arranged in the chamber (10), a heat shielding member (16) arranged above the crucible (12), and a dopant supply device (20) for supplying a dopant into the crucible (12) from the outside of the chamber (10). The dopant supply device (20) comprises a dopant supply pipe (21) which penetrates the chamber (10) to reach above the crucible (12). The dopant supply pipe (21) comprises a first dopant pipe (24) which penetrates the chamber (10), and a second dopant pipe (25) which is separated from the first dopant pipe (24) and arranged slightly below the first dopant pipe (24). The first dopant pipe (24) is separated from the heat shielding member (16). The second dopant pipe (25) is separated from the chamber (10) and arranged in the heat shielding member (16).

Description

Technical Field

[0001] This invention relates to a single crystal manufacturing apparatus, and more particularly to a dopant supply apparatus for supplying dopant before or during the Czochralski (CZ) process of producing single crystals. Background Technology

[0002] Single-crystal silicon, used as a substrate material for semiconductor devices, is mostly manufactured using the CZ (Crystallization-Zeroing) method. The CZ method involves immersing a seed crystal in molten silicon within a quartz crucible, and then slowly pulling the seed crystal up while rotating it and the crucible, growing a large-diameter single crystal beneath the seed crystal. According to the CZ method, high-quality silicon single-crystal ingots can be manufactured with high yield.

[0003] Various dopants are used to adjust the resistivity of monocrystalline silicon (hereinafter referred to as resistivity). Representative dopants include phosphorus (P), arsenic (As), antimony (Sb), and boron (B). These dopants are added to a quartz crucible along with polycrystalline silicon raw material and melted together with the silicon raw material by heating with a heater. This produces a silicon molten liquid containing a specified amount of dopant.

[0004] Dopant is sometimes added to the molten silicon during the crystal pulling process. For example, antimony has a lower melting point than phosphorus and boron because it evaporates very quickly under reduced pressure. Therefore, if it were melted together with the polycrystalline silicon raw material like phosphorus and boron, a large amount of dopant would evaporate during the initial stage of the crystal pulling process, failing to increase the dopant concentration in the molten silicon. Therefore, additional dopant is supplied during crystal pulling to prevent the dopant concentration in the molten silicon from decreasing.

[0005] Furthermore, even when using dopants with relatively slow evaporation rates, the supplied dopant segregates along the pulling direction of the single crystal, making it difficult to obtain uniform resistivity in that direction. To address this issue, it is effective to supply dopants not only during the initial loading of polycrystalline silicon but also during crystal pulling. For example, by adding a dopant of the same conductivity type as the initially loaded dopant, it is possible to pull two single-crystal silicon crystals with significantly different resistivities. Moreover, by adding a dopant of the opposite conductivity type to the initially loaded dopant, the crystal length of the single crystal with uniform resistivity in the pulling direction can be maximized.

[0006] Regarding methods for supplying dopant before or during the pulling of a single crystal, such as the dopant addition apparatus described in Patent Document 1, it comprises: a dopant supply tube penetrating the upper part of a chamber and reaching above a crucible inside the chamber; a sealing cap sealing the portion of the dopant supply tube penetrating the chamber; a dopant feeding hopper installed outside the chamber via a dopant supply valve to the dopant supply tube; and a connecting pipe connecting the dopant feeding hopper to the interior of the chamber. Although the chamber is in a reduced-pressure argon atmosphere when supplying dopant, this dopant addition apparatus can adjust the environment inside the dopant addition apparatus to be the same as that inside the chamber.

[0007] Furthermore, Patent Document 2 describes the following structure: In order to supply dopant to the raw material melt in the crucible without problems even when a heat shield is arranged above the crucible, a dopant supply tube arranged above the heat shield and inside the heat shield is led out from the middle to the outside of the heat shield, with at least the lower end of the dopant supply tube facing the outside of the heat shield. Existing technical documents Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 9-227275 Patent Document 2: Japanese Patent Application Publication No. 11-343196 Summary of the Invention The technical problem that the invention aims to solve

[0009] However, existing doping supply devices, due to their structure of fixing a single dopant supply tube to the chamber and the heat shield, frequently experience component breakage and detachment. Furthermore, existing dopant supply devices cannot accommodate structures where the heat shield can move vertically, or restrict the movement of the heat shield.

[0010] Therefore, the object of the present invention is to provide a single crystal manufacturing apparatus having a dopant supply device, wherein the dopant supply device has no component breakage or detachment and can also accommodate vertical movement of the heat shield member. Solutions for solving technical problems

[0011] To solve the above-mentioned technical problems, the single crystal manufacturing apparatus according to the present invention is characterized by comprising: a chamber; a crucible disposed in the chamber; a heat shield member disposed above the crucible; and a dopant supply device for supplying dopant to the crucible from the outside of the chamber; the dopant supply device comprising a dopant supply tube extending through the chamber to the top of the crucible; the dopant supply tube having: a first dopant tube extending through the chamber; and a second dopant tube separated from the first dopant tube and disposed slightly below the lower end of the first dopant tube; the first dopant tube being separated from the heat shield member; and the second dopant tube being separated from the chamber and disposed within the heat shield member.

[0012] According to the present invention, a single crystal manufacturing apparatus can be provided, which is easy to set up with dopant supply tubes, has no component breakage or detachment, and can also accommodate vertical movement of heat shielding components.

[0013] In this invention, the first doped tube and the second doped tube can be completely separated from each other, and a portion of the first doped tube can be inserted into the interior of the second doped tube. Furthermore, when the first doped tube and the second doped tube are completely separated, it is preferable that the upper opening of the second doped tube is positioned directly below the lower end of the first doped tube. By forming a structure in which the first doped tube and the second doped tube are mutually independent, the first doped tube can be separated from the heat shielding member, and the second doped tube can be separated from the chamber (especially the upper chamber).

[0014] In this invention, the second doped tube is preferably configured to be movable vertically relative to the heat shielding member. According to this structure, the second doped tube is easy to install, there is no risk of component breakage or detachment, and it can accommodate vertical movement of the heat shielding member.

[0015] In this invention, the second doped tube preferably has a large-diameter portion, a small-diameter portion, and a tapered portion; the large-diameter portion has an opening radius larger than the inner diameter of the lower end of the first doped tube, the small-diameter portion has an opening radius smaller than the large-diameter portion, and the tapered portion connects the large-diameter portion and the small-diameter portion. In this case, the large-diameter portion is positioned above the small-diameter portion, i.e., on the side of the first doped tube. According to this structure, the transfer from the first doped tube to the second doped tube can be accurately performed, and it is also easy to install the second doped tube on the heat-shielding member.

[0016] In this invention, the tapered angle (acute angle) of the outer surface of the tapered portion relative to the vertical axis is preferably less than the inclination angle of the inner wall surface of the heat shielding member facing the tapered portion relative to the vertical axis, and is particularly preferably approximately equal to the inclination angle of the inner wall surface of the heat shielding member. Therefore, the second doped tube can be supported by the heat shielding member in a point contact or line contact state, and damage or deformation of the second doped tube can be suppressed.

[0017] In this invention, it is preferable that the axis of the second doped tube extends in a straight line from the upper end to the lower end of the second doped tube. Therefore, a second doped tube that is easy and inexpensive to manufacture can be used.

[0018] In this invention, the dopant supply tube is preferably made of quartz. For example, if a carbon-based dopant supply tube is used, the carbon concentration in the single-crystal silicon may increase due to carbon contamination from the dopant. However, when the dopant supply tube is made of quartz, impurity contamination from the dopant can be prevented. Quartz tubes are easily broken at room temperature and may deform at high temperatures. However, when the second dopant tube is simply inserted into the through-hole of the heat shielding member, damage and deformation of the dopant supply tube can be prevented.

[0019] In this invention, the heat shielding member is preferably configured to move freely up and down within the chamber, and the relative positional relationship between the first doping tube and the second doping tube changes according to the movement of the heat shielding member. Therefore, in conjunction with the vertical movement of the heat shielding member, the entire length of the dopant supply tube can be adjusted, and the vertical movement of the heat shielding member is not restricted by the dopant supply tube. Furthermore, with the heat shielding member moving freely up and down, even if the crucible is filled with a large amount of solid raw material, interference between the heat shielding member and the solid raw material can be avoided by moving the heat shielding member upwards, thus increasing the initial filling amount of the molten metal.

[0020] In this invention, the chamber is preferably a main chamber having a main chamber for housing the crucible and an upper chamber having an upper opening covering the main chamber. The upper chamber is configured to be detachable from the main chamber, and the relative positional relationship between the first doped tube and the second doped tube changes depending on whether the upper chamber is installed or removed. In this case, since the first doped tube is fixed to the upper chamber side and the second doped tube is installed in the heat shielding member inside the main chamber, it is easy to install the upper chamber into or remove it from the main chamber.

[0021] In this invention, the second doped tube is inserted into the through hole formed in the heat shield member. The lower end of the second doped tube is not exposed and ends further inward than the lower opening end of the through hole. Preferably, the lower end of the second doped tube is covered by a carbon annular cap. Because the second doped tube is simply inserted into the through hole of the heat shield member, its installation is very simple. Furthermore, because the lower end of the second doped tube is not exposed and is covered by the annular cap, the lower end of the second doped tube can be protected from heat, preventing thermal deformation, etc.

[0022] In this invention, the outer opening of the annular cap is preferably oriented obliquely downwards towards the side wall of the crucible. Therefore, even if the second doping tube extends straight downwards, the dopant can be inserted as close to the inner wall of the crucible as possible, preventing molten metal splashing and dislocation of the single crystal during insertion. Invention Effects

[0023] According to the present invention, a single crystal manufacturing apparatus equipped with a dopant supply device can be provided, wherein the dopant supply device is free from component breakage or detachment and can also accommodate vertical movement of the heat shielding member. Attached Figure Description

[0024] Figure 1 This is a schematic side sectional view showing the structure of a single crystal manufacturing apparatus according to an embodiment of the present invention. Figure 2 yes Figure 1 An enlarged view of the dopant supply device. Figure 3 This is a schematic cross-sectional view showing the state of the heat shield component being raised during the preparation stage before the crystal pulling process begins. Figure 4 It is a schematic side sectional view showing the state of the disintegration chamber. Detailed Implementation

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic side sectional view showing the structure of a single crystal manufacturing apparatus according to an embodiment of the present invention.

[0027] like Figure 1As shown, the single crystal manufacturing apparatus 1 includes: a chamber 10; a quartz crucible 12 disposed within the chamber 10; a graphite base 13 supporting the quartz crucible 12; a rotating shaft 14 supporting the base 13 in a height-lifting and rotatable manner; a heater 15 disposed around the base 13; a heat shielding member 16 disposed above the quartz crucible 12; a single crystal pulling wire 17 disposed coaxially with the rotating shaft 14 above the quartz crucible 12; a winding mechanism 18 disposed above the chamber 10; and a dopant supply device 20 supplying dopant to the quartz crucible 12.

[0028] The chamber 10 consists of a main chamber 10a, an upper chamber 10b covering the upper opening of the main chamber 10a, and an elongated cylindrical crystal pulling chamber 10c connected to the upper opening of the upper chamber 10b. A quartz crucible 12, a base 13, a heater 15, and a heat shield 16 are disposed within the main chamber 10a. The base 13 is fixed to the upper end of a rotating shaft 14 that runs vertically through the center of the bottom of the chamber 10. The rotating shaft 14 is driven to move up and down and rotate by a rotating shaft drive mechanism 19.

[0029] Heater 15 is used to melt the polycrystalline silicon raw material filled in the quartz crucible 12 and produce molten silicon 3. Heater 15 is a carbon resistance heater and is configured to surround the quartz crucible 12 within the base 13. Insulating material 11 is disposed on the outside of heater 15. The insulating material 11 is arranged along the inner wall of the main chamber 10a, thereby improving the thermal insulation of the main chamber 10a.

[0030] A heat shield member 16 is provided to prevent the monocrystalline silicon from being heated by radiant heat from the heater 15 and the quartz crucible 12, and to suppress temperature fluctuations in the molten silicon 3. The heat shield member 16 is a generally cylindrical member with a diameter decreasing from top to bottom, covering the molten silicon 3 and surrounding the growing monocrystalline silicon 2. Graphite is preferably used as the material for the heat shield member 16. Because the lower end of the heat shield member 16 is located inside the quartz crucible 12, raising the quartz crucible 12 will not interfere with the heat shield member 16. An opening larger than the diameter of the monocrystalline silicon 2 is provided in the center of the heat shield member 16, through which the monocrystalline silicon 2 is lifted upwards.

[0031] Details will be described later, but preferably the heat shielding member 16 is configured to move freely up and down within the chamber 10. The heat shielding member 16 can be lifted by jacks or pulled by wires. With the heat shielding member 16 moving freely up and down, even if the quartz crucible 12 is filled with a large amount of solid silicon material, interference between the heat shielding member 16 and the solid silicon material can be avoided by moving the heat shielding member 16 to the top, which can increase the initial filling amount of silicon melt 3 in the quartz crucible 12.

[0032] Above the quartz crucible 12, a wire 17 serving as the pulling shaft for the monocrystalline silicon 2 and a winding mechanism 18 for winding the wire 17 are provided. The winding mechanism 18 has the function of rotating the monocrystalline silicon 2 together with the wire 17. The winding mechanism 18 is disposed above the crystal pulling chamber 10c, and the wire 17 extends from the winding mechanism 18 through the crystal pulling chamber 10c to the bottom, until the front end of the wire 17 reaches the internal space of the main chamber 10a. Figure 1 The image shows the single-crystal silicon 2 suspended by wire 17 during its growth process. When pulling the single crystal, the seed crystal is immersed in the molten silicon 3, and the wire 17 is slowly pulled up while the quartz crucible 12 and the seed crystal are rotated, thereby allowing the single crystal to grow.

[0033] At the upper part of the crystal pulling chamber 10c, a gas intake port 10d is provided for introducing argon gas into the chamber 10, and at the bottom of the main chamber 10a, a gas exhaust port 10e is provided for discharging the argon gas from the chamber 10. Argon gas is introduced into the chamber 10 through the gas intake port 10d, and the introduction rate is controlled by a valve. Furthermore, because the argon gas in the sealed chamber 10 is discharged to the outside of the chamber through the gas exhaust port 10e, SiO gas and CO gas in the chamber 10 can be recovered, keeping the chamber 10 clean.

[0034] The dopant supply device 20 includes a dopant supply pipe 21, a dopant hopper 22, and a sealing cap 23. The dopant supply pipe 21 passes through the chamber 10, and its lower end reaches above the quartz crucible 12. The dopant hopper 22 is located outside the chamber 10 and is connected to the upper end of the dopant supply pipe 21. The sealing cap 23 seals the opening 10f of the upper chamber 10b through which the dopant supply pipe 21 passes.

[0035] In the manufacture of monocrystalline silicon 2, a quartz crucible 12 is filled with polycrystalline silicon raw material, and a seed crystal is installed at the front end of the wire 17. Then, the silicon raw material in the quartz crucible 12 is heated by a heater 15 to generate molten silicon 3.

[0036] In the single-crystal pulling process, the seed crystal is first reduced in diameter using a buffer shrinking method to eliminate dislocations. Next, to obtain the desired diameter, a shoulder with a gradually increasing diameter is grown. Once the single crystal reaches the desired diameter, a body portion with a constant diameter is grown. After the body portion grows to the specified length, the tail portion is grown to separate the single crystal from the molten silicon in a dislocation-free state.

[0037] Before the pulling of single-crystal silicon 2 begins or during the crystal pulling process, dopant 5 is supplied from dopant supply device 20 to silicon melt 3.

[0038] Figure 2 yes Figure 1 An enlarged view of the dopant supply device 20.

[0039] like Figure 1 and Figure 2 As shown, the dopant supply device 20 includes a dopant supply pipe 21 that extends through the chamber 10 to the top of the quartz crucible 12, a dopant hopper 22 connected to the upper end of the dopant supply pipe 21, and a sealing cap 23 that seals the opening 10f formed in the upper chamber 10b. The dopant material supplied from the dopant hopper 22 is transported into the chamber 10 through the dopant supply pipe 21.

[0040] The dopant supply tube 21 is made of quartz glass and consists of a first dopant tube 24 pulled into the main chamber 10a through the opening 10f of the upper chamber 10b and a second dopant tube 25 disposed in the main chamber 10a slightly below the lower end of the first dopant tube 24.

[0041] The first doping tube 24 is a quartz glass tube that extends from the location of the dopant feed hopper 22 through the opening 10f of the upper chamber 10b, meandering to the area directly above the second doping tube 25. The first doping tube 24 is fixed to the upper chamber 10b via a sealing cap 23. The first doping tube 24 is detached and independent from the heat shield member 16.

[0042] The second doped tube 25 has a large-diameter portion 25a, a tapered portion 25b, and a small-diameter portion 25c; the large-diameter portion 25a has a larger opening radius than the lower end of the first doped tube 24, the opening radius of the tapered portion 25b gradually decreases, and the small-diameter portion 25c has a smaller opening radius than the large-diameter portion 25a. That is, the second doped tube 25 has a funnel shape in which the opening size at the upper end is larger than the opening size at the lower end.

[0043] The central axis of the second doped tube 25 extends in a straight line from its upper end to its lower end without any bends. Therefore, the second doped tube 25 can be installed on the heat shield member 16 simply by inserting the small-diameter portion 25c of the second doped tube 25 into the through hole 16a. This type of second doped tube 25 is easy to manufacture and inexpensive due to its simple shape. The second doped tube 25 is simply inserted into the through hole 16a of the heat shield member 16 and is configured to move vertically relative to the heat shield member 16. Furthermore, the second doped tube 25 is detachable and independent from the chamber 10.

[0044] A through hole 16a is provided in the heat shield member 16, extending vertically from its inner peripheral surface to its outer peripheral surface. The small-diameter portion 25c of the second doped tube 25 is inserted into the through hole 16a. Because the small-diameter portion 25c of the second doped tube 25 is surrounded by the heat shield member 16, the radiative heat from the heater 15 and the silicon melt 3 can be suppressed, preventing thermal deformation of the second doped tube 25.

[0045] The taper angle (acute angle) of the outer surface of the tapered portion 25b of the second doped tube 25 relative to the vertical axis is preferably approximately equal to the inclination angle of the inner wall surface 16b of the heat shield member 16 facing the tapered portion 25b relative to the vertical axis. This allows the second doped tube 25 to be supported in line contact with the heat shield member 16, suppressing breakage and deformation of the second doped tube 25. Furthermore, the apex of the taper angle is the lower end of the tapered portion 25b. The taper angle of the outer surface of the tapered portion 25b can be smaller than the inclination angle of the inner wall surface 16b facing the tapered portion 25b. In this case, the second doped tube 25 is supported by the heat shield member 16 at the point of connection of the tapered portion 25b, providing reliable support.

[0046] As described above, both the first doped tube 24 and the second doped tube 25 are made of quartz. For example, if at least one of the first doped tube 24 and the second doped tube 25 is made of carbon, the carbon concentration in the single crystal silicon will increase due to carbon contamination from the dopant. However, since both the first doped tube 24 and the second doped tube 25 are made of quartz, contamination from dopant impurities can be prevented. Furthermore, quartz tubes are prone to breakage at room temperature and may deform under high temperatures, but the second doped tube 25 is simply inserted into the through hole 16a of the heat shield member 16. Because it is not securely fixed with screws or the like, not only is its installation easier, but it also prevents damage and deformation of the second doped tube 25.

[0047] The lower end of the small-diameter portion 25c of the second doped tube 25 inserted into the through hole 16a of the heat shield member 16 is not exposed, and ends further inward than the lower opening end of the through hole 16a. The lower end of the second doped tube 25 is covered by a carbon annular cap 16c coated with SiC. Therefore, the lower end of the second doped tube 25 can be protected from heat, and thermal deformation can be prevented.

[0048] The outer opening of the annular cap 16c is preferably oriented diagonally downwards towards the side wall of the quartz crucible 12. Therefore, even if the second doping tube 25 extends vertically downwards, the dopant 5 can be inserted into the innermost part of the quartz crucible 12 (see reference). Figure 1 This can prevent molten metal from splashing during the pouring process and the dislocation of single crystals.

[0049] In the above structure, before the start of single-crystal silicon 2 pulling and during the crystal pulling process, granular dopant 5 is added to the silicon melt 3 in the quartz crucible 12 from the dopant supply device 20. The dopant 5 discharged from the dopant feed hopper 22 is supplied to the silicon melt 3 through the first doping tube 24 and the second doping tube 25.

[0050] Figure 3 This is a schematic cross-sectional view showing the state of the heat shield member 16 being raised during the preparation stage before the start of the crystal pulling process.

[0051] like Figure 3 As shown, during the preparation stage, in order to fill the quartz crucible 12 with as much silicon raw material 4 as possible, the solid silicon raw material 4 is piled up in the quartz crucible 12. By melting it, a large amount of molten silicon 3 can be generated. At this time, in order not to interfere with the polycrystalline silicon raw material, the heat shield member 16 is moved upwards to avoid interference from the piled-up silicon raw material 4. In addition, because the dopant supply pipe 21 is divided into the first doping pipe 24 and the second doping pipe 25, it can accommodate the movement of the heat shield member 16.

[0052] Figure 4 This is a schematic side sectional view showing the state of the disintegration chamber 10.

[0053] like Figure 4 As shown, chamber 10 is composed of a main chamber 10a, an upper chamber 10b, and a crystal pulling chamber 10c, which can be disassembled as illustrated. At this time, because the dopant supply tube 21 is separated into a first doping tube 24 and a second doping tube 25, it is easy to remove the main chamber 10a and install the upper chamber 10b. Thus, the relative positional relationship between the first doping tube 24 and the second doping tube 25 changes depending on the installation and removal of the upper chamber 10b.

[0054] As explained above, in this embodiment of the crystal manufacturing apparatus 1, the dopant supply pipe 21 for feeding dopant from the outside of the chamber 10 into the inside is divided into two parts. This allows for adjustment of the entire length of the dopant supply pipe 21 by coordinating with the vertical movement of the heat shield member 16. Furthermore, since the second doping pipe 25 only needs to be inserted into the through hole 16a of the heat shield member 16, not only is its installation easy, but damage and deformation can also be prevented.

[0055] The above describes preferred embodiments of the present invention. The present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention. These changes are of course included within the scope of the present invention.

[0056] For example, in the above embodiment, the dopant supply tube 21 is composed of two independent dopant tubes 24 and 25, but it can also be composed of three or more dopant tubes.

[0057] For example, in the crystal pulling process, the first doped tube 24 and the second doped tube 25 can be separated without overlapping in the vertical direction, but they can also overlap. Explanation of reference numerals in the attached figures

[0058] 1-Single crystal manufacturing apparatus, 2-Single crystal silicon, 3-Silicon melt, 4-Solid silicon raw material, 5-Dopant, 10-Cavity, 10a-Main chamber, 10b-Upper chamber, 10c-Crystal pulling chamber, 10d-Gas intake port, 10e-Gas exhaust port, 10f-Opening, 11-Insulation material, 12-Quartz crucible, 13-Base, 14-Rotating shaft, 15-Heater, 15b-Conical part, 16-Heat shielding structure Components, 16a-Through hole of heat shield component, 16b-Inner wall surface of heat shield component, 16c-Annular cover, 17-Wire, 18-Wire winding mechanism, 19-Shaft drive mechanism, 20-Dopant supply device, 21-Dopant supply tube, 22-Dopant hopper, 23-Sealing cover, 24-First doping tube, 25-Second doping tube, 25a-Large diameter section, 25b-Conical section, 25c-Small diameter section.

Claims

1. A single crystal manufacturing apparatus, characterized in that, include: Chamber; A crucible is disposed within the chamber; A heat shielding component is disposed above the crucible; as well as A dopant supply device supplies dopant into the crucible from outside the chamber; The dopant supply device includes a dopant supply tube that extends through the chamber to the top of the crucible; The dopant supply tube has: a first doping tube extending through the chamber; and a second doping tube separate from the first doping tube and disposed slightly below the lower end of the first doping tube. The first doped tube is separated and independent from the heat shielding component; The second doped tube has: a large-diameter portion having an opening radius larger than the inner diameter of the lower end of the first doped tube; a small-diameter portion having an opening radius smaller than the large-diameter portion; and a tapered portion connecting the large-diameter portion and the small-diameter portion. The second doped tube is separate from the chamber and is disposed within the heat shielding member. The lower end of the second doped tube is not in contact with the lower end of the first doped tube.

2. The single crystal manufacturing apparatus according to claim 1, wherein, The second doped tube is inserted into a through hole formed in the heat shield member, and the second doped tube is configured to move up and down relative to the heat shield member.

3. The single crystal manufacturing apparatus according to claim 1, wherein, The conical angle of the outer surface of the conical portion relative to the vertical axis is less than the inclination angle of the inner wall surface of the heat shielding member facing the conical portion relative to the vertical axis, wherein the conical angle is an acute angle.

4. The single crystal manufacturing apparatus according to claim 1, wherein, The axis of the second doped tube extends in a straight line from the upper end to the lower end of the second doped tube.

5. The single crystal manufacturing apparatus according to claim 1, wherein, The dopant supply tube is made of quartz.

6. The single crystal manufacturing apparatus according to any one of claims 1 to 5, wherein, The heat shielding component is configured to move freely up and down within the cavity, and the relative positional relationship between the first doped tube and the second doped tube changes according to the movement of the heat shielding component.

7. The single crystal manufacturing apparatus according to any one of claims 1 to 5, wherein, The chamber has a main chamber for housing the crucible and an upper chamber for covering the upper opening of the main chamber. The upper chamber is configured to be detachable from the main chamber, and the relative positional relationship between the first doped tube and the second doped tube changes depending on the detachment of the upper chamber.

8. The single crystal manufacturing apparatus according to claim 2, wherein, The lower end of the second doped tube is not exposed and ends further inside than the lower opening end of the through hole. The lower end of the second doped tube is covered by a carbon annular cap.

9. The single crystal manufacturing apparatus according to claim 8, wherein, The outer opening of the annular cap faces diagonally downwards, i.e., towards the side wall of the crucible.

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