Continuous Czochralski Single Crystal Fully Transparent Quartz-Lined Crucible, Its Preparation Method and Application

Abstract

This invention discloses a fully transparent quartz-lined crucible for continuous Czochralski single crystal pulling, its preparation method, and its application, belonging to the field of quartz crucible technology. The quartz-lined crucible includes a crucible body, which comprises a first transparent layer, a second transparent layer, and a third transparent layer arranged sequentially from the inside out. The total thickness of the crucible body is d, and the thicknesses of the first and third transparent layers are both 20%d to 30%d. This quartz-lined crucible exhibits excellent thermal insulation, is less prone to thermal stress problems, and can mitigate the adverse effects of temperature changes and fluctuations in the feeding area of ​​a continuous Czochralski single crystal pulling crucible on the liner crucible during crystal pulling. Furthermore, it can prevent cracking or deformation caused by thermal stress, increase the thermal shock resistance of the quartz crucible, and extend its service life. In addition, this quartz-lined crucible effectively avoids the severe bubble problem present in the outer layer of conventional semi-transparent crucibles, preventing the introduction of impurities due to bubble rupture during use.

Description

Technical Field

[0001] This invention relates to the field of quartz crucible technology, and more specifically, to a continuously Czochralski-grown single-crystal fully transparent quartz crucible with an inner liner, its preparation method, and its application. Background Technology

[0002] Continuous Czochralski (CCz) crystal pulling technology is one of the core processes for the fabrication of single-crystal silicon rods, primarily used in solar cells and the semiconductor industry. This technology improves production efficiency and optimizes crystal quality by simultaneously pulling and feeding the silicon rod.

[0003] CCz crucibles typically employ a double-layer structure consisting of an outer crucible and an inner crucible. The outer crucible is primarily used to contain the silicon material to be melted, and its bottom is designed with an arc shape to reduce thermal stress. The inner crucible is placed inside the outer crucible, with through holes on its bottom or sidewalls to form channels for the silicon material to enter the growth space. The interlayer between the outer and inner crucibles forms a feeding space for continuous feeding, enabling "simultaneous crystal pulling and feeding" and maintaining a stable liquid level.

[0004] In this technology, since both the inner and outer walls of the inner crucible are in contact with molten silicon, the temperature of the feeding zone in the jacket is affected by the cold silicon material added during continuous feeding, thus impacting the internal temperature of the inner crucible. Generally, to reduce the corrosion of quartz by molten silicon, the inner and outer walls of the inner crucible are coated with a coating (such as barium carbonate, boron nitride, zirconium oxide, or silicon carbide) to reduce oxygen content and extend lifespan. However, fully transparent crucibles have certain problems with temperature uniformity, resulting in poor heat insulation and heat preservation during use. Furthermore, fully transparent crucibles are prone to cracking or deformation due to thermal stress, leading to a shorter service life.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a continuously Czochralski-grown single crystal fully transparent quartz-lined crucible, its preparation method, and its application, so as to solve or improve the above-mentioned technical problems.

[0007] This invention can be implemented as follows:

[0008] In a first aspect, the present invention provides a continuously Czochralski-grown single crystal fully transparent quartz-lined crucible, comprising a crucible body, the crucible body comprising a first transparent layer, a second transparent layer, and a third transparent layer disposed sequentially from the inside out; before and after use, the bubble count in the first transparent layer and the third transparent layer of the crucible body does not exceed 10 bubbles / 17mm. 2 Before use, the number of air bubbles in the second transparent layer of the crucible body should not exceed 10 per 17mm. 2 After use, the second transparent layer of the crucible body contained 110 air bubbles per 17mm.2 ~120 pieces / 17mm 2 The total thickness of the crucible body before use is d, and the thickness of the first transparent layer and the third transparent layer before use is independently 20%d~30%d.

[0009] In an optional embodiment, the total thickness of the crucible body before use is 17mm to 18mm, and the thickness of the first transparent layer and the third transparent layer before use is independently 3mm to 5mm.

[0010] In an optional embodiment, the continuously Czochralski-grown single crystal fully transparent quartz-lined crucible also has at least one of the following characteristics:

[0011] Feature 1: The R-corner region of the continuously Czochralski-grown single crystal fully transparent quartz-lined crucible is provided with a silicon liquid flow channel, the diameter of which is 8mm~10mm;

[0012] Feature 2: The outer diameter of the fully transparent quartz crucible with continuous Czochralski single crystal lining is 800mm~820mm.

[0013] Secondly, the present invention provides a method for preparing a continuously Czochralski-grown single-crystal fully transparent quartz-lined crucible as described in any of the foregoing embodiments, comprising the following steps:

[0014] Quartz sand is laid and shaped in a rotating mold, and air inside the rotating mold and in the gaps between the quartz sand is removed; under vacuum and electric arc conditions, it is prepared in the following four stages:

[0015] The first stage is characterized by a vacuum of -0.06MPa to 0MPa, a current of 2500A to 3500A, an arc duration of 1 to 2 minutes, an electrode spacing of 60mm to 80mm, and a vertical distance of 200mm to 250mm between the arc-starting end of the electrode and the upper port of the rotating mold, so that the quartz sand in the arc-acting area forms a sealing layer.

[0016] The second stage: the vacuum degree is -0.095MPa to -0.099MPa, the current is 2000A to 2200A, the arc action time is 5min to 6min, the electrode spacing is 40mm to 45mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 200mm to 250mm, so that the quartz sand in the arc action area and the sealing layer together form the first transparent layer;

[0017] The third stage: the vacuum degree is -0.065MPa to -0.070MPa, the current is 3500A to 3800A, the arc action time is 2min to 3min, the electrode spacing is 35mm to 40mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 120mm to 150mm, so that the quartz sand in the arc action area forms a second transparent layer;

[0018] The fourth stage involves a vacuum of -0.095MPa to -0.099MPa, a current of 2300A to 2500A, an arc duration of 6 to 8 minutes, an electrode spacing of 50mm to 55mm, and a vertical distance of 150mm to 180mm between the arc-starting end of the electrode and the upper port of the rotating mold, so that the quartz sand in the arc-acting area forms a third transparent layer.

[0019] In an optional embodiment, the purity of the quartz sand is not less than 99.9999%; the particle size of the quartz sand is 100μm~150μm.

[0020] In an optional implementation, the mold rotates at a speed of 70 rpm to 72 rpm throughout the entire preparation process.

[0021] Thirdly, the present invention provides a continuous Czochralski single crystal crucible, comprising an outer quartz crucible and a continuously Czochralski single crystal fully transparent inner liner quartz crucible of any of the foregoing embodiments, wherein the continuously Czochralski single crystal fully transparent inner liner quartz crucible is spaced apart inside the outer quartz crucible.

[0022] In an optional embodiment, the outer quartz crucible has at least one of the following features:

[0023] Feature 3: The total thickness of the outer quartz crucible is 15mm~16mm;

[0024] Feature 4: The outer diameter of the outer quartz crucible is 930mm~960mm.

[0025] In an optional embodiment, the distance between the bottom of the continuously Czochralski-grown single crystal fully transparent inner quartz crucible and the bottom of the outer quartz crucible is 30mm to 50mm.

[0026] In an optional embodiment, the distance between the outer wall of the straight arm region in the continuously Czochralski-grown fully transparent inner liner quartz crucible and the inner wall of the straight arm region in the outer quartz crucible is 70mm~80mm.

[0027] The beneficial effects of this invention include:

[0028] This invention utilizes a second transparent layer designed as a bubble growth layer. During use, extremely small bubbles within the layer, or bubbles molten into the glass, gradually expand to form larger bubbles, creating a "bubble growth layer" that also serves as an insulation layer. This "bubble growth layer" effectively constructs a thermal barrier within the quartz crucible. The low thermal conductivity of the gas in the "bubble growth layer" significantly reduces heat transfer efficiency, forcing heat to diffuse more evenly within the crucible (rather than directional loss). This reduces temperature gradients across different areas of the crucible, achieving a uniform thermal field and preventing cracking or deformation due to thermal stress. The specially designed three transparent layers provide superior insulation for the quartz-lined crucible, reducing the likelihood of thermal stress problems. This mitigates the adverse effects of temperature variations and fluctuations in the feeding area of ​​the continuous Czochralski single-crystal crucible on the lining crucible during crystal pulling, and prevents cracking or deformation caused by thermal stress, thus extending the service life of the quartz-lined crucible. In addition, this quartz-lined crucible can effectively avoid the serious problem of bubbles in the outer layer of conventional semi-transparent crucibles, prevent impurities from being introduced during use by bubble rupture, and thus improve the performance of single crystal silicon rods. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the continuous Czochralski single crystal crucible provided by the present invention;

[0031] Figure 2 A schematic diagram of the crucible body in a fully transparent quartz-lined crucible for continuous Czochralski crystal growth;

[0032] Figure 3 This is a slice of the straight-wall region of the continuously Czochralski single-crystal fully transparent quartz-lined crucible provided in Example 1 of the experimental case after use;

[0033] Figure 4 This is a slice of the R-angle region of the continuously pulled single crystal fully transparent quartz-lined crucible provided in Example 1 of the experimental case after use.

[0034] Icons: 10-Continuous Czochralski single crystal fully transparent inner liner quartz crucible; 11-Silicon liquid flow channel; 12-First transparent layer; 13-Second transparent layer; 14-Third transparent layer; 20-Outer quartz crucible; 30-Interlayer feeding area; 40-Single crystal silicon rod. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0036] The following provides a detailed description of the continuously Czochralski single-crystal fully transparent quartz-lined crucible, its preparation method, and its application.

[0037] like Figure 1 As shown, the present invention provides a continuously Czochralski-grown single crystal fully transparent quartz-lined crucible 10, including a crucible body, as shown in the figure. Figure 2 As shown, the crucible body includes a first transparent layer 12, a second transparent layer 13, and a third transparent layer 14 arranged sequentially from the inside to the outside.

[0038] It should be noted that the first transparent layer 12 and the third transparent layer 14 of the continuously Czochralski single crystal fully transparent quartz crucible 10 proposed in this invention are essentially bubble-free (also referred to as "bubble-free layers") before and after use, and bubble expansion is essentially nonexistent; while the second transparent layer 13 has small bubbles before use, which expand during use to form a transparent bubble layer (also referred to as "bubble growth layer"). The number of bubbles in the first transparent layer 12 and the third transparent layer 14 before use does not exceed 10 per 17 mm. 2 Furthermore, the number of air bubbles after use does not exceed 10 per 17mm. 2 The second transparent layer 13 should contain no more than 10 air bubbles per 17mm before use. 2 And after use, it contains 110 air bubbles per 17mm. 2 ~120 pieces / 17mm 2 .

[0039] In some optional embodiments, the first transparent layer 12 contains 5 air bubbles per 17 mm before use. 2 ~7 pieces / 17mm 2 After use, the number of air bubbles is 3 per 17mm. 2 ~5 pieces / 17mm 2 The second transparent layer 13 contained 8 air bubbles per 17 mm before use. 2 ~9 pieces / 17mm 2 After use, the number of air bubbles is 112 per 17mm. 2 ~118 pieces / 17mm 2 The third transparent layer 14 contained 5 air bubbles per 17mm before use. 2 ~6 pieces / 17mm2 After use, the number of air bubbles is 4 per 17mm. 2 ~5 pieces / 17mm 2 .

[0040] Regarding the second transparent layer 13, during its preparation, a higher current and a melting rate exceeding the vacuuming rate prevent bubbles from escaping the second-stage transparent layer, keeping them within the crucible body. The bubbles formed in this stage exist in an extremely small form, with some also melting into the quartz glass. During use, these extremely small bubbles begin to expand, and the bubbles molten in the transparent layer re-precipitate under high temperature, forming new bubbles. This causes the second-stage transparent layer to form a "bubble growth layer" after use, acting as a "thermal insulation layer." This "bubble growth layer" essentially constructs a "thermal barrier" within the quartz crucible. The low thermal conductivity of the gas in the "bubble growth layer" significantly reduces heat transfer efficiency, forcing heat to diffuse more evenly within the crucible (rather than directional loss), thereby reducing the temperature gradient across different areas of the crucible, achieving a uniform thermal field, and preventing cracking or deformation due to thermal stress.

[0041] By setting the above-mentioned special three-layer transparent layer, the influence of temperature fluctuation in the feeding section on the internal temperature fluctuation of the inner lining crucible during crystal pulling can be effectively reduced.

[0042] The effects of temperature fluctuations include:

[0043] 1) Oxygen content out of control: Temperature fluctuations and the SiO2+Si→SiO↑ reaction occur, oxygen is incorporated into the silicon melt, resulting in excessive oxygen content;

[0044] 2) Dislocation density: Abrupt temperature gradients lead to instability at the solid-liquid interface, resulting in localized undercooling or overheating, causing lattice defects and a decrease in electrical properties;

[0045] 3) Impurity streaks: Disrupted thermal convection causes uneven distribution of dopants (such as boron and phosphorus), resulting in resistivity fluctuations;

[0046] 4) The crystallization layer of the crucible peels off, forming suspended particles, causing polycrystalline nucleation, resulting in edge breakage and polycrystalline parasitism.

[0047] In this invention, the total thickness of the crucible body before use is d, and the thickness of the first transparent layer 12 and the third transparent layer 14 before use is independently 20%d to 30%d, such as 20%d, 22%d, 25%d, 28%d or 30%d, etc., or other values ​​within the range of 20%d to 30%d.

[0048] In some alternative implementations, the total thickness of the crucible body before use can be 17mm to 18mm, such as 17mm, 17.5mm or 18mm, or other values ​​within the range of 17mm to 18mm.

[0049] The thickness of the first transparent layer 12 and the third transparent layer 14 before use can each be independently 3mm to 5mm, such as 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, or other values ​​within the range of 3mm to 5mm. Before use, the thickness of the second transparent layer 13 is the total thickness of the crucible body minus the thickness of the first transparent layer 12 and the thickness of the third transparent layer 14.

[0050] If the thickness of the first transparent layer 12 and the third transparent layer 14 is too thin (i.e., the thickness of the second transparent layer 13 is too thick), the molten silicon may come into contact with the second transparent layer 13 during the continuous erosion of the inner and outer layers of the quartz crucible. This can cause bubbles to burst at high temperatures, and the detached quartz particles can enter the molten silicon, increasing the impurities in the single-crystal silicon purity. Furthermore, contact between the molten silicon and the second transparent layer 13 can easily lead to silicon perforation and silicon infiltration into the quartz crucible, significantly reducing the service life of the quartz crucible. If the thickness of the first transparent layer 12 and the third transparent layer 14 is too thick (i.e., the thickness of the second transparent layer 13 is too thin), it can easily lead to poor thermal insulation performance, thermal stress cracking or deformation, and weakened thermal shock resistance of the quartz crucible.

[0051] In some optional embodiments, a silicon liquid flow channel 11 is provided in the R-corner region of the continuously Czochralski fully transparent inner quartz crucible 10. The diameter of the silicon liquid flow channel 11 can be 8mm to 10mm, such as 8mm, 8.5mm, 9mm, 9.5mm or 10mm, or other values ​​in the range of 8mm to 10mm.

[0052] If the diameter of the silicon melt flow channel 11 is too small, it means that the solid silicon material is added rapidly in a very concentrated small area, which can easily lead to localized overcooling, thereby disturbing crystal growth and even causing impurity precipitation and the formation of microcrystals. Furthermore, it can easily cause turbulent melt convection, affecting the overall quality of the crystal rod. In addition, it can easily cause silicon melt splashing, which can easily cause dislocations when it falls onto the crystal rod or the solid-liquid interface, leading to crystal pulling failure. If the diameter of the silicon melt flow channel 11 is too large, it can easily lead to insufficient melting; it can also make it difficult to control volatiles and liquid level; in addition, it can reduce the efficiency of the thermal field and increase energy consumption.

[0053] The outer diameter of the continuously Czochralski single crystal fully transparent inner liner quartz crucible 10 can be 800mm~820mm, such as 800mm, 805mm, 810mm, 815mm or 820mm, or other values ​​within the range of 800mm~820mm.

[0054] As mentioned above, the continuous Czochralski single crystal fully transparent quartz-lined crucible 10 provided by the present invention can have good heat insulation and heat preservation properties during use, which can avoid or reduce the problem of conventional quartz-lined crucibles being prone to cracking or deformation due to thermal stress, thereby extending the service life of the quartz-lined crucible.

[0055] Accordingly, the present invention also provides a method for preparing the above-mentioned continuously Czochralski single-crystal fully transparent inner liner quartz crucible 10, comprising the following steps:

[0056] Quartz sand is laid in a rotating mold to form a shape, and the air in the rotating mold and the air in the gaps between the quartz sand are removed; under vacuum and electric arc, it is prepared in the following four stages.

[0057] In some optional embodiments, the purity of the quartz sand is not less than 99.9999%; the particle size of the quartz sand can be 100μm~150μm, such as 100μm, 110μm, 120μm, 130μm, 140μm or 150μm, or other values ​​in the range of 100μm~150μm.

[0058] If the particle size of the quartz sand is less than 100 μm, the small particles are packed very tightly, with extremely small gaps between them. During melting, the high-viscosity melt almost completely seals these tiny gaps, making it difficult for trapped gases and reaction gases to escape. This results in a large number of dense, non-escaping microbubbles, filling areas that should be bubble-free with bubbles and negating their barrier function against erosion. Furthermore, if the particle size of the quartz sand is too small, it will lead to a large sintering shrinkage rate, making it prone to cracking and significantly reducing the mechanical strength and thermal shock resistance of the quartz-lined crucible. If the particle size of the quartz sand is greater than 150μm, the large particles will not melt completely or the fusion between particles will be insufficient, leaving tiny gaps and interfaces in the crucible. These areas will become "fast channels" for silicon erosion at high temperatures, with an erosion rate much higher than that of dense quartz glass. Furthermore, if the particle size of the quartz sand is too large, the gaps between the particles will be even larger when they are stacked. These large gaps can easily form large bubbles during the melting process. Due to the high viscosity of the melt, it is even more difficult for large bubbles to escape from the liquid surface.

[0059] In some alternative implementations, the rotational speed of the mold during the entire preparation process can be 70 rpm to 72 rpm, such as 70 rpm, 71 rpm or 72 rpm, or other values ​​within the range of 70 rpm to 72 rpm.

[0060] It should be noted that the feasible methods for laying and shaping quartz sand and removing air mentioned above can be found in relevant existing technologies. As long as the above effects can be achieved, this application will not elaborate on or limit the above operations.

[0061] In this application, the first stage mainly involves forming a sealing layer of quartz sand in the arc-affected area.

[0062] The vacuum level at this stage can be -0.06MPa to 0MPa, such as -0.06MPa, -0.05MPa, -0.04MPa, -0.03MPa, -0.02MPa, -0.01MPa or 0MPa, or other values ​​within the range of -0.06MPa to 0MPa.

[0063] The current in this stage can be 2500A~3500A, such as 2500A, 2800A, 3000A, 3200A or 3500A, or other values ​​within the range of 2500A~3500A.

[0064] The duration of the electric arc in this stage can be 1 to 2 minutes, such as 1 minute, 1.5 minutes, or 2 minutes, or other values ​​within the range of 1 to 2 minutes.

[0065] The electrode spacing in this stage can be 60mm~80mm, such as 60mm, 65mm, 70mm, 75mm or 80mm, or other values ​​within the range of 60mm~80mm.

[0066] During this stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold can be 200mm~250mm, such as 200mm, 210mm, 220mm, 230mm, 240mm or 250mm, or other values ​​within the range of 200mm~250mm.

[0067] In some alternative implementations, the thickness of the cover layer can be approximately 0.5 mm.

[0068] In this application, the second stage mainly involves forming a first transparent layer 12 by combining the quartz sand in the arc-acting area and the sealing layer.

[0069] The vacuum level at this stage can be from -0.095MPa to -0.099MPa, such as -0.095MPa, -0.096MPa, -0.097MPa, -0.098MPa, or -0.099MPa, or other values ​​within the range of -0.095MPa to -0.099MPa.

[0070] The current in this stage can be 2000A~2200A, such as 2000A, 2050A, 2100A, 2150A or 2200A, or other values ​​within the range of 2000A~2200A.

[0071] The duration of the electric arc during this stage can be 5 to 6 minutes, such as 5 minutes, 5.5 minutes, or 6 minutes, or other values ​​within the range of 5 to 6 minutes.

[0072] The electrode spacing in this stage can be 40mm~45mm, such as 40mm, 41mm, 42mm, 43mm, 44mm or 45mm, or other values ​​within the range of 40mm~45mm.

[0073] During this stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold can be 200mm~250mm, such as 200mm, 210mm, 220mm, 230mm, 240mm or 250mm, or other values ​​within the range of 200mm~250mm.

[0074] If the current in the second stage is less than 2000A or the arc duration is less than 5 minutes, it can easily lead to a thin first transparent layer 12, insufficient melting, and a loose structure. Furthermore, it can cause bubbles to be difficult to remove, resulting in poor quality or failure to form the first transparent layer 12. If the current in the second stage is greater than 2200A or the arc duration is longer than 6 minutes, bubbles can easily remain in the melt and cannot be effectively removed. If the electrode spacing in the second stage is less than 40mm, it can easily lead to insufficient arc irradiation, concentrating at the bottom and rounded corners. If the electrode spacing in the second stage is greater than 45mm, it can easily lead to insufficient arc irradiation, concentrating on the straight wall. If the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold in the second stage is less than 200mm, it can easily lead to insufficient arc irradiation, concentrating at the bottom and rounded corners. If the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold in the second stage is greater than 250mm, it can easily lead to insufficient arc irradiation, concentrating on the straight wall.

[0075] In this application, the third stage mainly involves forming a second transparent layer 13 in the quartz sand in the arc-affected area.

[0076] The vacuum level at this stage can be from -0.065MPa to -0.070MPa, such as -0.065MPa, -0.066MPa, -0.067MPa, -0.068MPa, -0.069MPa, or -0.07MPa, or other values ​​within the range of -0.065MPa to -0.070MPa.

[0077] The current in this stage can be 3500A~3800A, such as 3500A, 3550A, 3600A, 3650A, 3700A, 3750A or 3800A, or other values ​​within the range of 3500A~3800A.

[0078] The duration of the electric arc during this stage can be 2 to 3 minutes, such as 2 minutes, 2.5 minutes, or 3 minutes, or other values ​​within the range of 2 to 3 minutes.

[0079] The electrode spacing in this stage can be 35mm~40mm, such as 35mm, 36mm, 37mm, 38mm, 39mm or 40mm, or other values ​​within the range of 35mm~40mm.

[0080] During this stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold can be 120mm~150mm, such as 120mm, 125mm, 130mm, 135mm, 140mm, 145mm or 150mm, or other values ​​within the range of 120mm~150mm.

[0081] If the current in the third stage is less than 3500A or the arc duration is less than 2 minutes, the second transparent layer 13 is likely to be thin, preventing bubbles from being trapped in the quartz in large quantities. If the current in the third stage is greater than 3800A or the arc duration is longer than 3 minutes, current impact is likely, causing R-corner bubbles to accumulate. If the electrode spacing in the third stage is less than 35mm, arc impact is likely, causing R-corner bubbles to accumulate. If the electrode spacing in the third stage is greater than 40mm, port impact is likely, causing the molten quartz at the straight-wall port to slide down. If the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold in the third stage is less than 120mm, arc impact is likely, causing R-corner bubbles to accumulate. If the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold in the third stage is greater than 150mm, port impact is likely, causing the molten quartz at the straight-wall port to slide down.

[0082] The fourth stage mainly involves forming a third transparent layer 14 in the quartz sand within the arc-affected area.

[0083] The vacuum level at this stage can be between -0.095 MPa and -0.099 MPa, such as -0.095 MPa, -0.096 MPa, -0.097 MPa, -0.098 MPa, or -0.099 MPa, or other values ​​within the range of -0.095 MPa to -0.099 MPa.

[0084] The current in this stage can be 2300A~2500A, such as 2300A, 2350A, 2400A, 2450A or 2500A, or other values ​​within the range of 2300A~2500A.

[0085] The duration of the electric arc in this stage can be 6 to 8 minutes, such as 6 minutes, 6.5 minutes, 7 minutes, 7.5 minutes or 8 minutes, or other values ​​within the range of 6 minutes to 8 minutes.

[0086] The electrode spacing in this stage can be 50mm~55mm, such as 50mm, 51mm, 52mm, 53mm, 54mm or 55mm, or other values ​​within the range of 50mm~55mm.

[0087] During this stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold can be 150mm~180mm, such as 150mm, 155mm, 160mm, 165mm, 170mm, 175mm or 180mm, or other values ​​within the range of 150mm~180mm.

[0088] If the current in the fourth stage is less than 2300A or the arc duration is less than 6 minutes, it can easily lead to a thin third transparent layer 14, insufficient melting, and a loose structure. Furthermore, it can make it difficult to remove bubbles, resulting in poor quality or failure to form the third transparent layer 14. If the current in the fourth stage is greater than 2500A or the arc duration is longer than 8 minutes, bubbles can easily remain in the melt. If the electrode spacing in the fourth stage is less than 50mm, insufficient arc irradiation can occur, concentrating at the bottom and rounded corners. If the electrode spacing in the fourth stage is greater than 55mm, insufficient arc irradiation can occur, concentrating on the straight wall. If the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold in the fourth stage is less than 150mm, insufficient arc irradiation can occur, concentrating at the bottom and rounded corners. If the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold in the fourth stage is greater than 180mm, insufficient arc irradiation can occur, concentrating on the straight wall.

[0089] After preparation, simply cool and demold.

[0090] Continuing from the above, in the second stage, a bubble-free expansion layer (first transparent layer 12) is formed on the inner surface of the crucible by using a small current, an ultimate vacuum, and specific electrode spacing and positions. Then, in the third stage, a large current is used to accelerate melting and reduce the vacuum level, along with specific electrode spacing and positions. In this stage, some vacuum suction can hold the sand layer, allowing the quartz sand on the straight wall of the crucible to move less or avoid under the suction, thus melting the bubbles inside the transparent layer to form the second transparent layer 13. In the fourth stage, a bubble-free expansion layer (third transparent layer 14) is formed on the outer surface of the crucible by using a small current, an ultimate vacuum, and specific electrode spacing and positions. The transparent state of the three transparent layers prepared by this method shows no layering phenomenon (because the bubbles have melted into the glass layer and cannot be observed with the naked eye). The small bubbles in the second transparent layer 13 expand during use to form a bubble layer, which can avoid the problems of poor heat preservation and easy generation of thermal stress in fully transparent crucibles. In addition, the third transparent layer 14 without bubble expansion is set on the outer wall of the inner lining crucible, which can avoid the problem of severe bubbles in the outer layer of traditional inner lining crucibles, bubble rupture during use, and the introduction of more impurities into the feeding layer.

[0091] In addition, the present invention also provides a continuous Czochralski single crystal crucible, see [link to relevant documentation]. Figure 1 and Figure 2 It includes an outer quartz crucible 20 and the aforementioned continuously Czochralski-grown single crystal fully transparent inner quartz crucible 10, with the continuously Czochralski-grown single crystal fully transparent inner quartz crucible 10 spaced apart within the outer quartz crucible 20. The area between the continuously Czochralski-grown single crystal fully transparent inner quartz crucible 10 and the outer quartz crucible 20 can be referred to as the interlayer feeding area 30.

[0092] It should be noted that the outer quartz crucible 20 in this invention can be the same as the outer quartz crucible 20 commonly used in the continuous Czochralski single crystal method. The connection method between the fully transparent inner liner quartz crucible 10 and the outer quartz crucible 20 in the continuous Czochralski single crystal method is not limited or elaborated in this invention.

[0093] In some alternative embodiments, the total thickness of the outer quartz crucible 20 can be 15mm to 16mm, such as 15mm, 15.5mm or 16mm, or other values ​​within the range of 15mm to 16mm.

[0094] The outer diameter of the outer quartz crucible 20 can be 930mm~960mm, such as 930mm, 940mm, 950mm or 960mm, or other values ​​within the range of 930mm~960mm.

[0095] In some optional embodiments, the distance between the bottom of the continuously Czochralski-grown single crystal fully transparent inner liner quartz crucible 10 and the bottom of the outer quartz crucible 20 can be 30mm to 50mm, such as 30mm, 35mm, 40mm, 45mm or 50mm, or other values ​​within the range of 30mm to 50mm.

[0096] In some optional embodiments, the distance between the outer wall of the straight arm region in the continuously Czochralski fully transparent inner liner quartz crucible 10 and the inner wall of the straight arm region in the outer quartz crucible 20 can be 70mm to 80mm, such as 70mm, 75mm or 80mm, or other values ​​within the range of 70mm to 80mm.

[0097] In conclusion, by using the aforementioned continuous Czochralski single-crystal crucible, the oxygen content of the silicon melt can be effectively reduced, the lattice defects of the single-crystal silicon rod 40 can be reduced, and the electrical performance of the single-crystal silicon rod 40 can be improved.

[0098] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0099] Example 1

[0100] This embodiment provides a continuously grown Czochralski single crystal fully transparent quartz-lined crucible 10, which includes a crucible body. The crucible body includes a first transparent layer 12, a second transparent layer 13, and a third transparent layer 14 arranged sequentially from the inside to the outside. The outer diameter of the continuously grown Czochralski single crystal fully transparent quartz-lined crucible 10 is 810 mm, and a silicon liquid flow channel 11 is formed in the R-corner region. The diameter of the silicon liquid flow channel 11 is 10 mm.

[0101] The preparation of the continuously Czochralski single-crystal fully transparent quartz-lined crucible 10 includes the following steps:

[0102] Quartz sand (purity 99.9999%, particle size 100μm~150μm) was laid and shaped in a rotating mold (speed 70rpm), and air in the rotating mold and air in the gaps between the quartz sand was removed; under vacuum and electric arc, it was prepared in the following four stages:

[0103] The first stage: the vacuum degree is -0.05MPa, the current is 3000A, the arc action time is 1.5min, the electrode spacing is 70mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 220mm, so that the quartz sand in the arc action area forms a sealing layer.

[0104] Second stage: vacuum degree is -0.096MPa, current is 2100A, arc action time is 5.5min, electrode spacing is 42mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 220mm, so that the quartz sand in the arc action area and the sealing layer together form the first transparent layer 12.

[0105] The third stage: the vacuum degree is -0.068MPa, the current is 3650A, the arc action time is 2.5min, the electrode spacing is 38mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 135mm, so that the quartz sand in the arc action area forms a second transparent layer 13.

[0106] Fourth stage: vacuum degree is -0.096MPa, current is 2400A, arc action time is 6.5min, electrode spacing is 52mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 165mm, so that the quartz sand in the arc action area forms a third transparent layer 14.

[0107] Example 2

[0108] The difference between this embodiment and Example 1 lies in the preparation conditions, as detailed below:

[0109] Quartz sand (purity 99.9999%, particle size 100μm~150μm) was laid and shaped in a rotating mold (speed 71rpm), and air in the rotating mold and air in the gaps between the quartz sand was removed; under vacuum and electric arc, it was prepared in the following four stages:

[0110] The first stage: the vacuum degree is -0.06MPa, the current is 2500A, the arc action time is 1min, the electrode spacing is 60mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 200mm, so that the quartz sand in the arc action area forms a sealing layer.

[0111] Second stage: vacuum degree is -0.095MPa, current is 2000A, arc action time is 5min, electrode spacing is 40mm, and vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 250mm, so that the quartz sand in the arc action area and the sealing layer together form the first transparent layer 12.

[0112] The third stage: the vacuum degree is -0.065MPa, the current is 3500A, the arc action time is 2min, the electrode spacing is 40mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 150mm, so that the quartz sand in the arc action area forms a second transparent layer 13.

[0113] Fourth stage: vacuum degree is -0.095MPa, current is 2300A, arc action time is 6min, electrode spacing is 50mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 180mm, so that the quartz sand in the arc action area forms a third transparent layer 14.

[0114] Example 3

[0115] The difference between this embodiment and Example 1 lies in the preparation conditions, as detailed below:

[0116] Quartz sand (purity 99.9999%, particle size 100μm~150μm) was laid and shaped in a rotating mold (speed 72rpm), and air in the rotating mold and air in the gaps between the quartz sand was removed; under vacuum and electric arc, it was prepared in the following four stages:

[0117] First stage: vacuum degree is 0MPa, current is 3500A, arc action time is 2min, electrode spacing is 80mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 250mm, so that the quartz sand in the arc action area forms a sealing layer.

[0118] Second stage: vacuum degree is -0.099MPa, current is 2200A, arc action time is 6min, electrode spacing is 45mm, and vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 200mm, so that the quartz sand in the arc action area and the sealing layer together form the first transparent layer 12.

[0119] The third stage: the vacuum degree is -0.070MPa, the current is 3800A, the arc action time is 3min, the electrode spacing is 35mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 120mm, so that the quartz sand in the arc action area forms a second transparent layer 13.

[0120] Fourth stage: vacuum degree is -0.099MPa, current is 2500A, arc action time is 8min, electrode spacing is 55mm, and the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 150mm, so that the quartz sand in the arc action area forms a third transparent layer 14.

[0121] Example 4

[0122] The difference between this embodiment and Embodiment 1 is that the outer diameter of the continuous Czochralski single crystal fully transparent inner liner quartz crucible 10 is 800 mm, and the diameter of the silicon liquid flow channel 11 with a diameter of 10 mm is opened in the R-corner region.

[0123] Example 5

[0124] The difference between this embodiment and Embodiment 1 is that the outer diameter of the continuous Czochralski single crystal fully transparent inner liner quartz crucible 10 is 820 mm, and the diameter of the silicon liquid flow channel 11 with a radius of 8 mm is opened in the R-corner region.

[0125] Table 1 shows some of the properties of the continuous Czochralski single crystal fully transparent inner quartz crucible 10 prepared in Examples 1-3 above.

[0126] Table 1 Indicator Table

[0127]

[0128] Comparative example:

[0129] The difference between Comparative Example 1-1 and Example 1 is that the current is 1800A in the second stage;

[0130] The difference between Comparative Examples 1-2 and Example 1 is that the current is 2500A in the second stage;

[0131] The difference between Comparative Examples 1-3 and Example 1 is that the arcing time in the second stage is 2 minutes.

[0132] The difference between Comparative Examples 1-4 and Example 1 is that the arcing time in the second stage is 8 minutes.

[0133] The difference between Comparative Examples 1-5 and Example 1 is that the electrode spacing is 35 mm in the second stage;

[0134] The difference between Comparative Examples 1-6 and Example 1 is that the electrode spacing is 50 mm in the second stage;

[0135] The difference between Comparative Examples 1-7 and Example 1 is that in the second stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 180mm.

[0136] The difference between Comparative Examples 1-8 and Example 1 is that in the second stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 280mm.

[0137] The difference between Comparative Example 2-1 and Example 1 is that the current is 3200A in the third stage;

[0138] The difference between Comparative Example 2-2 and Example 1 is that the current is 4000A in the third stage;

[0139] The difference between Comparative Examples 2-3 and Example 1 is that the arc duration in the third stage is 1 minute.

[0140] The difference between Comparative Examples 2-4 and Example 1 is that the arcing time in the third stage is 5 minutes.

[0141] The difference between Comparative Examples 2-5 and Example 1 is that the electrode spacing is 30 mm in the third stage;

[0142] The difference between Comparative Examples 2-6 and Example 1 is that the electrode spacing is 45 mm in the third stage;

[0143] The difference between Comparative Examples 2-7 and Example 1 is that in the third stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 100mm.

[0144] The difference between Comparative Examples 2-8 and Example 1 is that in the third stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 180mm.

[0145] The difference between Comparative Example 3-1 and Example 1 is that the current is 2000A in the fourth stage;

[0146] The difference between Comparative Example 3-2 and Example 1 is that the current is 2800A in the fourth stage;

[0147] The difference between Comparative Example 3-3 and Example 1 is that the arc duration in the fourth stage is 4 minutes.

[0148] The difference between Comparative Examples 3-4 and Example 1 is that the arcing time in the fourth stage is 10 minutes.

[0149] The difference between Comparative Examples 3-5 and Example 1 is that the electrode spacing is 48 mm in the fourth stage;

[0150] The difference between Comparative Examples 3-6 and Example 1 is that the electrode spacing is 58 mm in the fourth stage;

[0151] The difference between Comparative Examples 3-7 and Example 1 is that in the fourth stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 120mm.

[0152] The difference between Comparative Examples 3-8 and Example 1 is that in the fourth stage, the vertical distance between the arc-starting end of the electrode and the upper port of the rotating mold is 200mm.

[0153] Test case

[0154] The continuous Czochralski crystal fully transparent inner liner quartz crucibles 10 provided in Examples 1-5 and each comparative example are placed in the same position and connection method within the same type of outer quartz crucible 20 to form a continuous Czochralski crystal crucible. The outer quartz crucible 20 has a total thickness of 15 mm and an outer diameter of 945 mm. The distance between the bottom of the continuous Czochralski crystal fully transparent inner liner quartz crucible 10 and the bottom of the outer quartz crucible 20 is 40 mm. The distance between the outer wall of the straight arm region in the continuous Czochralski crystal fully transparent inner liner quartz crucible 10 and the inner wall of the straight arm region in the outer quartz crucible 20 is 75 mm.

[0155] (1) Taking Example 1 as an example, the cross-sectional view of the straight-wall region of the continuous Czochralski single-crystal fully transparent inner-lined quartz crucible 10 prepared in this example after use is shown in the figure below. Figure 3 As shown, the slice diagram of the R-angle region is as follows: Figure 4 As shown.

[0156] Depend on Figure 3 and Figure 4 It can be seen that after use, the first transparent layer 12 and the third transparent layer 14 of the continuously Czochralski single crystal fully transparent inner liner 10 are basically free of bubbles, while the second transparent layer 13 has a large number of uniformly distributed bubbles.

[0157] (2) Single crystal silicon rods 40 were prepared using the above-mentioned continuous Czochralski single crystal crucibles, and the differences in various properties were compared. The results are shown in Tables 2 to 5. Among them, the oxygen content was determined by FTIR; the resistance was determined by the four-probe method; "radial resistance non-uniformity of single crystal silicon rod 40" refers to the fluctuation of resistivity values ​​along the crystal growth direction (axial direction) and the cross section (radial direction) perpendicular to the growth direction; the service life refers to the crystal pulling temperature of 1420℃~1550℃.

[0158] Table 2 Performance Table

[0159]

[0160] Table 3 Performance Table

[0161]

[0162] Table 4 Performance Table

[0163]

[0164] Table 5 Performance Table

[0165]

[0166] As can be seen from Tables 2 to 5, improper preparation conditions in the second, third, or fourth stages will lead to a deterioration in the performance of the single crystal silicon rod 40 and a shortened crucible lifespan when the inner-lined quartz crucible is continuously pulled into single crystals.

[0167] In summary, the quartz-lined crucible provided by this invention has superior thermal insulation properties, is less prone to thermal stress problems, and can mitigate the adverse effects of temperature variations and fluctuations in the feeding zone of a continuous Czochralski single-crystal crucible on the inner-lined crucible during crystal pulling. Furthermore, it can prevent cracking or deformation caused by thermal stress, extending the service life of the inner-lined quartz crucible. In addition, this quartz-lined crucible effectively avoids the severe bubble problem present in the outer layer of conventional semi-transparent crucibles, preventing the introduction of impurities due to bubble rupture during use, thereby improving the performance of the single-crystal silicon rod 40.

[0168] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing a continuous Czochralski monocrystal fully transparent inner quartz crucible, characterized by, The method comprises the following steps: The quartz sand is laid and formed in a rotating mold, and air in the rotating mold and air in the gaps between the quartz sands is removed; under vacuum and arc action, the quartz sand is prepared in the following four stages: In the first stage, the vacuum degree is-0.06 MPa to 0 MPa, the current is 2500 A to 3500 A, the arc action time is 1 min to 2 min, the electrode spacing is 60 mm to 80 mm, and the vertical distance between the arc starting end of the electrode and the upper port of the rotating mold is 200 mm to 250 mm, so that the quartz sand in the arc action area forms a sealing layer; In the second stage, the vacuum degree is-0.095 MPa to-0.099 MPa, the current is 2000 A to 2200 A, the arc action time is 5 min to 6 min, the electrode spacing is 40 mm to 45 mm, and the vertical distance between the arc starting end of the electrode and the upper port of the rotating mold is 200 mm to 250 mm, so that the quartz sand in the arc action area and the sealing layer jointly form a first transparent layer; In the third stage, the vacuum degree is-0.065 MPa to-0.070 MPa, the current is 3500 A to 3800 A, the arc action time is 2 min to 3 min, the electrode spacing is 35 mm to 40 mm, and the vertical distance between the arc starting end of the electrode and the upper port of the rotating mold is 120 mm to 150 mm, so that the quartz sand in the arc action area forms a second transparent layer; In the fourth stage, the vacuum degree is-0.095 MPa to-0.099 MPa, the current is 2300 A to 2500 A, the arc action time is 6 min to 8 min, the electrode spacing is 50 mm to 55 mm, and the vertical distance between the arc starting end of the electrode and the upper port of the rotating mold is 150 mm to 180 mm, so that the quartz sand in the arc action area forms a third transparent layer.

2. The production method according to claim 1, characterized by, The purity of the quartz sand is not less than 99.9999%, and the particle size of the quartz sand is 100 μm to 150 μm.

3. The production method according to claim 1 or 2, characterized by, During the whole preparation process, the rotating speed of the mold is 70 rpm to 72 rpm.

4. A fully transparent inner lining quartz crucible for continuous Czochralski single crystal growth, characterized by, The continuous Czochralski monocrystal fully transparent inner lining quartz crucible is prepared by the preparation method in any one of claims 1-3, and comprises a crucible body, wherein the crucible body comprises a first transparent layer, a second transparent layer and a third transparent layer arranged from inside to outside; the number of bubbles in the first transparent layer and the third transparent layer is not more than 10 / 17mm 2 before and after use of the crucible body; the number of bubbles in the second transparent layer is not more than 10 / 17mm 2 before use of the crucible body, and the number of bubbles in the second transparent layer is 110 / 17mm 2 ~120 / 17mm 2 after use of the crucible body; the total thickness of the crucible body before use is d, and the thickness of the first transparent layer and the third transparent layer before use is independently 20%d~30%d.

5. The fully transparent inner liner fused quartz crucible for continuous Czochralski single crystal growth according to claim 4, wherein The total thickness of the crucible body before use is 17 mm to 20 mm, and the thickness of the first transparent layer and the third transparent layer before use is independently 3.5 mm to 6 mm.

6. The fully transparent inner quartz crucible for continuous single crystal pulling according to claim 4 or 5, characterized in that The continuous Czochralski single crystal full-transparent inner lining quartz crucible also has at least one of the following characteristics: Characteristic 1: The R-angle area of the continuous Czochralski single crystal full-transparent inner lining quartz crucible is provided with a silicon liquid flow channel, and the diameter of the silicon liquid flow channel is 8 mm to 10 mm; Characteristic 2: The outer diameter of the continuous Czochralski single crystal full-transparent inner lining quartz crucible is 800 mm to 820 mm.

7. A continuous Czochralski single crystal crucible, characterized by, The outer quartz crucible and the continuous Czochralski single crystal full-transparent inner lining quartz crucible according to any one of claims 4 to 6 are arranged in the outer quartz crucible.

8. The continuous Czochralski single crystal ingot crucible of claim 7, wherein, The outer quartz crucible has at least one of the following characteristics: Characteristic 3: The total thickness of the outer quartz crucible is 15 mm to 16 mm; Characteristic 4: The outer diameter of the outer quartz crucible is 930 mm to 960 mm.

9. The continuous Czochralski single crystal ingot crucible of claim 7 or 8, wherein The distance between the bottom of the continuous Czochralski single crystal full-transparent inner lining quartz crucible and the bottom of the outer quartz crucible is 30-50 mm.

10. The continuous Czochralski single crystal ingot crucible of claim 7 or 8, wherein The distance between the outer wall of the straight arm area in the continuous Czochralski single crystal full-transparent inner lining quartz crucible and the inner wall of the straight arm area in the outer quartz crucible is 70-80 mm.

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