Monocrystalline silicon rod and preparation method thereof, silicon wafer and solar cell

Abstract

The invention discloses a silicon single crystal rod and a preparation method thereof, a silicon wafer and a solar cell, and belongs to the technical field of photovoltaic module preparation. The single crystal silicon rod contains an antimony element and a hydrogen element, the doping concentration of the antimony element in the single crystal silicon rod is Ca, the doping concentration of the hydrogen element in the single crystal silicon rod is Cb, and Ca / Cb is greater than or equal to 1E <-3 > and less than or equal to 4E + 2. According to the silicon single crystal rod provided by the invention, the antimony and the hydrogen are doped at the same time, and the effective segregation coefficient of the antimony in the crystalline silicon is improved through the interaction of the hydrogen and the antimony, so that the resistivity change uniformity of the silicon single crystal rod is improved, the oxygen content of the silicon single crystal rod is improved, the service life of the silicon single crystal rod is prolonged, and the resistivity is accurately controlled; the resistivity of the monocrystalline silicon rod and the derivative product thereof is more uniform and concentrated, and the performance and the production efficiency of the czochralski monocrystalline silicon and the battery can be effectively improved.

Description

[0001] This application claims priority to Chinese Patent Application No. 202411590194.5, filed on November 8, 2024, entitled "A Single Crystal Silicon Rod and its Preparation Method, Silicon Wafer and Battery", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of semiconductor technology, specifically relating to a single-crystal silicon rod and its preparation method, a silicon wafer, and a solar cell. Background Technology

[0003] In photovoltaic cells, monocrystalline silicon rods are the core material, and their performance directly affects the efficiency and stability of the cells. However, in the current production process of monocrystalline silicon rods, while doping with a single element can improve the oxygen content and lifespan of the silicon wafer and control resistivity, the resistivity range of a single dopant element is highly dependent on the element's segregation coefficient. This results in poor uniformity of element distribution across different parts of the pulled monocrystalline silicon rod from head to tail. This leads to inconsistent resistivity variations throughout the rod, which can severely impact the performance of the photovoltaic cells. Summary of the Invention

[0004] The purpose of this application is to provide a monocrystalline silicon rod and its preparation method, a silicon wafer, and a solar cell, which improves the uniformity of resistivity change of the monocrystalline silicon rod by simultaneously doping it with antimony and hydrogen.

[0005] This application provides a single-crystal silicon rod containing antimony and hydrogen elements, wherein the antimony doping concentration in the single-crystal silicon rod is C. a The hydrogen doping concentration in the single-crystal silicon rod is C. b The following condition is satisfied: 1E-3≤C a / C b ≤4E+2.

[0006] In some embodiments, the single-crystal silicon rod further satisfies: 2.5E-1≤C a / C b ≤3.5E+2.

[0007] In some embodiments, the doping concentration C of the antimony element in the single-crystal silicon rod a Satisfy: 1E+14cm -3 ≤C a ≤8E+15cm -3 .

[0008] In some embodiments, the doping concentration C of the antimony element in the single-crystal silicon rod a Satisfies: 2E+14cm-3 ≤C a ≤7E+15cm -3 .

[0009] In some embodiments, the doping concentration C of the antimony element in the single-crystal silicon rod a Satisfy: 1E+15cm -3 ≤C a ≤7E+15cm -3 .

[0010] In some embodiments, the hydrogen doping concentration C in the single-crystal silicon rod b Satisfy: 2E+13cm -3 ≤C b ≤1E+17cm -3 .

[0011] In some embodiments, the hydrogen doping concentration C in the single-crystal silicon rod b Satisfy: 1E+15cm -3 ≤C b ≤7E+16cm -3 .

[0012] In some embodiments, the hydrogen doping concentration C in the single-crystal silicon rod b Satisfying: 3E+15cm -3 ≤C b ≤6E+16cm -3 .

[0013] In some embodiments, the single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail disposed opposite to each other along the length direction, wherein the antimony doping concentration at the head is C. a1 The antimony element has a doping concentration of C at the tail. a2 , satisfying: 0≤|C a1 -C a2 | / C a2 ≤0.8.

[0014] In some embodiments, the single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail disposed opposite to each other along the length direction, wherein the hydrogen doping concentration at the head is C. b1 The hydrogen doping concentration at the tail is C. b2 , satisfying: 0≤|C b1 -C b2 | / C b2 ≤0.8.

[0015] In some embodiments, the antimony element is doped at a concentration C in the head. a1Satisfies: 2E+14cm -3 ≤C a1 ≤8E+15cm -3 .

[0016] In some embodiments, the doping concentration C of the antimony element at the tail is... a2 Satisfy: 1E+14cm -3 ≤C a2 ≤7E+15cm -3 .

[0017] In some embodiments, the hydrogen element is doped at a concentration C in the head. b1 Satisfy: 2E+13cm -3 ≤C b1 ≤1E+17cm -3 .

[0018] In some embodiments, the hydrogen doping concentration C at the tail is... b2 Satisfy: 2E+13cm -3 ≤C b1 ≤1E+17cm -3 .

[0019] In some embodiments, the single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail disposed opposite to each other along the length direction. From the head to the tail, the single-crystal silicon rod is divided into N silicon rod units, and each silicon rod unit includes a first end and a second end disposed opposite to each other along the length direction, the first end being near the head and the second end being near the tail; the single-crystal silicon rod further satisfies: 0 ≤ |C| n-1 -C n | / C n ≤0.8;

[0020] Among them, C n C represents the doping concentration of antimony at the second end of the nth silicon rod unit; n-1 This represents the doping concentration of antimony at the first end of the silicon rod unit in the nth segment; n is an integer greater than or equal to 2.

[0021] In some embodiments, the single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail disposed opposite to each other along the length direction. From the head to the tail, the single-crystal silicon rod is divided into S-segment silicon rod units. Each silicon rod unit includes a first end and a second end disposed opposite to each other along the length direction, the first end being near the head and the second end being near the tail. The single-crystal silicon rod further satisfies: 0 ≤ |C| s-1 -C s | / C s ≤0.8;

[0022] Among them, C s C represents the hydrogen doping concentration at the second end of the s-th silicon rod unit; s-1 This represents the doping concentration of antimony at the first end of the silicon rod unit in the s-th segment; n is an integer greater than or equal to 2.

[0023] In some embodiments, any one of the n silicon rod units has the same dimension in the length direction.

[0024] In some embodiments, the dimension of any one of the n silicon rod units in the length direction is A mm, satisfying: 1≤A≤50.

[0025] In some embodiments, n is an integer greater than or equal to 2 and less than or equal to 3000.

[0026] In some embodiments, the single-crystal silicon rod satisfies at least one of the following characteristics:

[0027] 1) 1E+14cm -3 ≤C n ≤8E+15cm -3 ;

[0028] 2) 1E+14cm -3 ≤C n-1 ≤8E+15cm -3 ;

[0029] 3) 2E+13cm -3 ≤C s ≤1E+17cm -3 ;

[0030] 4) 2E+13cm -3 ≤C s-1 ≤1E+17cm -3 .

[0031] In some embodiments, this application also provides a method for preparing a single-crystal silicon rod, characterized in that it includes:

[0032] A silicon raw material is provided, and a single crystal silicon rod is obtained through the steps of material preparation, repeated feeding, temperature stabilization, crystal pulling, shoulder formation, equal diameter formation, and finishing. In at least one of the steps of material preparation, repeated feeding, temperature stabilization, crystal pulling, shoulder formation, equal diameter formation, and finishing, hydrogen gas is introduced into the silicon raw material. Before the crystal pulling step, an antimony-containing elemental metal or alloy is added to the silicon raw material.

[0033] Specifically, before the single-crystal silicon rod is fully grown, the doping concentration during the solidification process of the single-crystal silicon rod is adjusted to control the doping ratio of hydrogen and antimony to meet the following requirements:

[0034] 1E-3≤C a / C b ≤4E+2;

[0035] In the formula, C a C represents the doping concentration of the antimony element in the single-crystal silicon rod. b The hydrogen doping concentration in the single-crystal silicon rod is given.

[0036] In some embodiments, the time for introducing hydrogen gas into the silicon raw material satisfies:

[0037] t 总 =t1+t2+t3+t4+t5+t6+t7, and 0.5h≤t 总 ≤82h;

[0038] Among them, t 总 The total time for introducing hydrogen is t1, which is the time for introducing hydrogen during the material preparation stage; t2 is the time for introducing hydrogen during the re-feeding stage; t3 is the time for introducing hydrogen during the temperature stabilization stage; t4 is the time for introducing hydrogen during the crystallization stage; t5 is the time for introducing hydrogen during the shoulder formation stage; t6 is the time for introducing hydrogen during the equal diameter stage; and t7 is the time for introducing hydrogen during the finishing stage.

[0039] In some embodiments, the time for introducing hydrogen gas into the silicon raw material also satisfies:

[0040] t1: t2: t3: t4: t5: t6: t7=(0~10): (0~8): (0~2): (0~1.5): (0~3):

[0041] (0~55): (0~2).

[0042] In some embodiments, the method for preparing single-crystal silicon rods further includes: after the re-feeding step, introducing a protective gas into the silicon raw material;

[0043] The hydrogen gas and the protective gas form a mixed gas, wherein the volume percentage of the hydrogen gas in the mixed gas is 1-90%, preferably 5-90%.

[0044] In some embodiments, the flow rate of the hydrogen gas is 0.0001 to 180 slpm.

[0045] In some embodiments, the flow rate of the protective gas is 40 to 200 slpm.

[0046] In some embodiments, before the end of the re-addition step and the beginning of the equal diameter step, the volatilization rate η of the antimony element is controlled to satisfy:

[0047] η=(H1 / 100mm)×100%-15%;

[0048] Wherein, H1 is the liquid outlet distance in the single crystal furnace, in mm; the volatility η satisfies: 5% ≤ η ≤ 25%; the liquid outlet distance H1 satisfies: 20mm ≤ H1 ≤ 40mm.

[0049] In some embodiments, a flow guide tube is provided inside the single crystal furnace, the flow guide tube comprising a first section and a second section connected to each other, satisfying the following:

[0050] tanα = H2 / W1, and 0 ≤ tanα ≤ 0.58;

[0051] Where α is the angle formed by the second segment and the first direction, in °; H2 is the height of the projection of the second segment in the second direction, in mm; W1 is the length of the projection of the second segment in the first direction, in mm; and the first direction and the second direction intersect.

[0052] In some embodiments, the guide tube has a maximum diameter D max ,satisfy:

[0053] D max ≥2W1+W2;

[0054] The first segment and the second segment together form a receiving cavity. The end of the receiving cavity near the liquid surface of the molten silicon has a through hole. W2 is the maximum size of the through hole along the first direction, in mm.

[0055] In some embodiments, this application also provides a silicon wafer prepared from the aforementioned single-crystal silicon rod; the silicon wafer contains antimony and hydrogen; wherein the concentration of the antimony is 1E+14cm⁻¹. -3 Up to 8E+15cm -3 The concentration of hydrogen is 2E+13cm. -3 Up to 1E+17cm -3 .

[0056] In some embodiments, the concentration of antimony is 2E+14cm⁻¹. -3 Up to 7E+15cm -3 The concentration of hydrogen is 1E+15cm. -3 Up to 7E+16cm -3 .

[0057] In some embodiments, the concentration of antimony is 1E+15cm⁻¹. -3 Up to 7E+15cm -3 The concentration of hydrogen is 3E+15cm. -3 Up to 6E+16cm -3 .

[0058] In some embodiments, this application also provides a solar cell, including a silicon substrate, said silicon substrate being prepared from a silicon wafer as described in any of the above embodiments;

[0059] The resistivity of the silicon substrate is 0.5-3 Ω·cm, and the thickness is 120-160 μm.

[0060] In some embodiments, the silicon substrate includes a doped region in which hydrogen and antimony elements are doped;

[0061] The hydrogen concentration in the doped region is 2E+13cm⁻¹ -3 ~1E+17cm -3 ;

[0062] The antimony concentration in the doped region is 1E+14cm⁻¹ -3 ~8E+15cm -3 .

[0063] The beneficial effects of this application are as follows: Compared with the prior art, this application provides a single-crystal silicon rod containing antimony and hydrogen elements, wherein the doping concentration of antimony in the single-crystal silicon rod is C. a The hydrogen doping concentration in a single-crystal silicon rod is C. b The following condition is satisfied: 1E-3≤C a / C b ≤4E+2. The single-crystal silicon rod provided in this application is doped with both antimony and hydrogen. Through the interaction between hydrogen and antimony, the effective segregation coefficient of antimony in the crystalline silicon is improved, thereby enhancing the uniformity of resistivity variation in the single-crystal silicon rod; simultaneously, when 1E-3≤C a / C b Within the range of ≤4E+2, hydrogen and antimony can affect the number of impurities in single crystals, further enabling the resistivity to meet design requirements within different ranges. This is not limited by the segregation coefficient of a single element, and can improve the oxygen content and lifespan of single crystal silicon rods, achieving precise resistivity control. This results in more uniform and concentrated resistivity in single crystal silicon rods and their derivatives, effectively improving the performance and production efficiency of Czochralski-grown single crystal silicon and solar cells. It should be noted that the methods for preparing silicon wafers and single crystal silicon rods in the embodiments of this application include all the technical features and beneficial effects of the aforementioned single crystal silicon rods, and will not be repeated here. Attached Figure Description

[0064] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0066] Figure 1 This is a schematic diagram of the structure of a single crystal furnace provided in an embodiment of this application;

[0067] Figure 2 for Figure 1 A magnified view of part A in the middle;

[0068] Figure 3 A top view of the top cover of a single crystal furnace provided in an embodiment of this application;

[0069] Figure 4 This is a schematic diagram of the structure of a gas flow region inside a single crystal furnace, provided in an embodiment of this application.

[0070] Figure 5 This application provides a schematic diagram of a single-crystal silicon rod divided into N silicon rod units.

[0071] Figure 6 This is a schematic diagram of a single-crystal silicon rod divided into S-segment silicon rod units, provided as an embodiment of this application.

[0072] Explanation of reference numerals in the attached figures:

[0073] 10-Guide tube, 11-First section, 12-Second section, 13-Containing cavity, 14-Through hole, 20-Top cover, 21-First vent hole, 22-Second vent hole, 30-Crucible, 40-Silicon liquid, 50-First gas flow area, 60-Second gas flow area, 61-First area, 62-Second area, 100-Single crystal furnace. Detailed Implementation

[0074] The technical solutions of the embodiments of this application 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 this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0075] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection, an indirect connection through an intermediate medium, or an indirect connection through a pipe or conduit; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically limited. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0076] This application provides a single-crystal silicon rod containing antimony and hydrogen elements, wherein the antimony doping concentration in the single-crystal silicon rod is C. a The hydrogen doping concentration in a single-crystal silicon rod is C. b The following condition is satisfied: 1E-3≤C a / C b ≤4E+2.

[0077] In some embodiments, C a / C b The value can be any one of 1E-3, 1E-2, 2.5E-1, 1E-1, 1E+1, 2E+1, 2E+2, 3E+2, 3.5E+2, 4E+2, or a range between any two values.

[0078] It is understandable that the single-crystal silicon rod of this application, due to the simultaneous doping of antimony and hydrogen, improves the effective segregation coefficient of antimony in silicon through the interaction between hydrogen and antimony, resulting in a more uniform distribution of antimony in the single-crystal silicon rod, when 1E-3≤C a / C b Within the range ≤4E+2, the uniform distribution of antimony and hydrogen improves the uniformity of resistivity changes in monocrystalline silicon rods. This further improves the oxygen content and lifetime of monocrystalline silicon rods and enables precise resistivity control. The more uniform and concentrated resistivity of monocrystalline silicon rods and their derivatives means more consistent electron transport within the rods, reducing electron diffusion and scattering, and improving the efficiency and stability of photovoltaic cells. Furthermore, the uniform and concentrated resistivity makes the electrical properties of monocrystalline silicon rods easier to control and adjust; electron transport paths are shorter, current resistance is lower, and energy consumption of electronic devices can be further reduced.

[0079] In some embodiments, doping concentration refers to the number of atoms of the doping element per unit volume of a single-crystal silicon rod.

[0080] In some embodiments, the single-crystal silicon rod further satisfies: 2.5E-1≤C a / C b ≤3.5E+2.

[0081] In some embodiments, C a / C b The value can be any one of 2.5E-1, 1E-1, 1E+1, 2E+1, 2E+2, 3E+2, 3.5E+2 or a range between any two values.

[0082] In some embodiments, the doping concentration C of antimony in a single-crystal silicon rod a Satisfy: 1E+14cm -3 ≤C a ≤8E+15cm -3 For example, it could be 1E+14cm -3 2E+14cm -3 3E+14cm -3 4E+14cm -3 5E+14cm -3 6E+14cm -3 7E+14cm -3 8E+14cm -3 9E+14cm -3 1E+15cm -3 2E+15cm -3 3E+15cm -3 4E+15cm -3 5E+15cm -3 6E+15cm -3 7E+15cm -3 8E+15cm -3 The range between any one or any two values ​​in the range.

[0083] In some embodiments, the doping concentration C of antimony in a single-crystal silicon rod a Satisfies: 2E+14cm -3 ≤C a ≤7E+15cm -3 .

[0084] In some embodiments, the doping concentration C of antimony in a single-crystal silicon rod a Satisfy: 1E+15cm -3 ≤C a ≤7E+15cm -3 .

[0085] It is understandable that when C a Satisfying 1E+14cm -3 ≤C a ≤8E+15cm -3 Within a certain range, antimony doping in rods can introduce additional electrons or holes, altering the conductivity of silicon. These additional charge carriers can increase the conductivity of silicon, thereby reducing resistivity. Simultaneously, antimony doping can interact with hydrogen atoms in silicon to form a complex doping system, further modulating the conductivity and resistivity of silicon to ensure a uniform resistivity distribution.

[0086] In some embodiments, the hydrogen doping concentration C in the single-crystal silicon rod b Satisfy: 2E+13cm -3 ≤C b ≤1E+17cm -3 For example, it could be 2E+13cm -3 3E+13cm -3 4E+13cm -3 5E+13cm -3 8E+13cm -3 1E+14cm -3 2E+14cm -3 5E+14cm -3 8E+14cm -3 1E+15cm -3 2E+15cm -3 5E+15cm -3 8E+15cm -3 1E+16cm -3 5E+16cm -3 6E+16cm -3 7E+16cm -3 1E+17cm -3 The range between any one or any two values ​​in the range.

[0087] In some embodiments, the hydrogen doping concentration C in the single-crystal silicon rod b Satisfy: 1E+15cm -3 ≤C b ≤7E+16cm -3 .

[0088] In some embodiments, the hydrogen doping concentration C in the single-crystal silicon rod b Satisfying: 3E+15cm -3 ≤C b ≤6E+16cm -3 .

[0089] It is understandable that when C b When the above ranges are met, the interaction between hydrogen and antimony can be achieved, improving the effective segregation coefficient of antimony doping in crystalline silicon and thus enhancing the uniformity of resistivity distribution in single-crystal silicon. Simultaneously, hydrogen doping in silicon can introduce additional electrons, forming chemical bonds between hydrogen atoms and silicon. These additional electrons can increase the conductivity of silicon materials, thereby reducing resistivity. Hydrogen can also interact with impurities or defects in silicon materials, reducing interference from impurities or defects on electron transport and further improving the consistency of conductivity and resistivity. Furthermore, some hydrogen elements can passivate and attract impurities and defects within silicon crystals, improving the minority carrier lifetime of single-crystal silicon rods and simultaneously regulating the uniformity of radial and axial resistivity distribution in single-crystal silicon rods.

[0090] In some embodiments, the single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail disposed opposite each other along the length direction, wherein the antimony doping concentration at the head is C. a1 The doping concentration of antimony at the tail is C. a2 , satisfying: 0≤|C a1 -C a2 | / C a2 ≤0.8.

[0091] It is understandable that during the constant diameter stage of a single-crystal silicon rod, any length range is cut, with the front section of constant diameter growth designated as the head and the rear section of constant diameter growth designated as the tail.

[0092] It should be noted that the diffusion of antimony in single-crystal silicon is the main reason for the difference in doping concentration. 0≤|C a1 -C a2 | / C a2 The parameter range of ≤0.8 reflects the degree of antimony doping concentration variation at the head and tail. By controlling the difference in antimony doping concentration between the head and tail within a certain range, the diffusion rate and extent of antimony can be controlled, reducing the diffusion difference of antimony in the single-crystal silicon rod and thus improving the uniformity of distribution. Furthermore, single-crystal silicon rods have an ordered lattice structure, and antimony doping introduces lattice defects. When the difference in antimony doping concentration between the head and tail is within a certain range, the difference in lattice defects can also be reduced, making the lattice structure more uniform. This helps improve the uniformity of electron transport in the lattice, thereby improving the uniformity of resistivity.

[0093] In some embodiments, the doping concentration C of antimony in the head is... a1 Satisfies: 2E+14cm -3 ≤C a1 ≤8E+15cm -3 The doping concentration of antimony at the tail end, C a2 Satisfy: 1E+14cm-3 ≤C a2 ≤7E+15cm -3 It is understandable that the antimony doping concentration at the head is slightly higher than that at the tail, which can further achieve uniformity in the resistivity variation of the single-crystal silicon rod.

[0094] In some embodiments, the single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail disposed opposite each other along the length direction, and the hydrogen doping concentration in the head is C. b1 The hydrogen doping concentration at the tail is C. b2 , satisfying: 0≤|C b1 -C b2 | / C b2 ≤0.8.

[0095] Understandably, a difference in hydrogen doping concentration between the head and tail sections within a certain range can achieve a more uniform impurity distribution, reducing impurity concentration inhomogeneity and improving the uniformity of resistivity variation in the single-crystal silicon rod. This is especially true when 0 ≤ |C| is satisfied. b1 -C b2 | / C b2 When the hydrogen doping concentration is ≤0.8, the difference between the head and tail is small, which can reduce the gradient change of resistivity in the single crystal silicon rod, making the resistivity change more gradual and reducing the non-uniformity of resistivity.

[0096] In some embodiments, the hydrogen doping concentration C in the head b1 Satisfy: 2E+13cm -3 ≤C b1 ≤1E+17cm -3 The hydrogen doping concentration C at the tail b2 Satisfy: 2E+13cm -3 ≤C b1 ≤1E+17cm -3 The hydrogen doping concentration at the head can be equal to that at the tail, or it can be less than that at the tail, or it can be greater than that at the tail. When the difference in hydrogen doping concentration is small, the electron transport speed and direction in the material are more consistent, reducing the diffusion and scattering of electron flow.

[0097] In some embodiments, such as Figure 5 As shown, the single-crystal silicon rod has a length direction and includes a head and a tail arranged opposite each other along the length direction. From the head to the tail, the single-crystal silicon rod is divided into N silicon rod units. Each silicon rod unit includes a first end and a second end opposite each other along the length direction, with the first end near the head and the second end near the tail. The single-crystal silicon rod further satisfies: 0 ≤ |C| n-1 -C n | / Cn ≤0.8; where C n C represents the doping concentration of antimony at the second end of the nth silicon rod unit; n-1 This represents the doping concentration of antimony at the first end of the nth silicon rod unit; n is an integer greater than or equal to 2; N is an integer greater than or equal to 2. It is understood that n ≤ N.

[0098] In some embodiments, the value of N is based on the actual length of the monocrystalline silicon rod. For example, when N is 2, the monocrystalline silicon rod is divided into two segments, with the first end corresponding to the head position and the second end corresponding to the tail position in each segment.

[0099] In some embodiments, any one of the N silicon rod units has the same dimensions along its length. It is understood that when the dimensions are equal, each silicon rod unit can be considered as having the same unit structure.

[0100] In some embodiments, the dimension of any one of the N silicon rod units in the length direction is A mm, satisfying: 1 ≤ A ≤ 50. For example, A can be any one value or a range between any two values ​​from 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, 36 mm, 37 mm, 38 mm, 39 mm, 40 mm, 41 mm, 42 mm, 43 mm, 44 mm, 45 mm, 46 mm, 47 mm, 48 mm, 49 mm, and 50 mm. The length of a silicon rod unit is determined by the overall length of the single-crystal silicon rod and the number of segments that need to be divided.

[0101] Furthermore, the preferred dimension Amm can be in the range of 5mm to 20mm; the more preferred dimension Amm can be in the range of 10mm to 15mm.

[0102] In some embodiments, n is an integer greater than or equal to 2 and less than or equal to 3000, and N is an integer greater than or equal to 2 and less than or equal to 3000. In some other embodiments, n is an integer greater than or equal to 2 and less than or equal to 60, and N is an integer greater than or equal to 2 and less than or equal to 60. For example, taking a single-crystal silicon rod with a total length of 6000mm as an example, when it needs to be divided into 2 segments, N is 3000; when it needs to be divided into 50 segments, N is 60. Similarly, the total length of the single-crystal silicon rod can also be any one of 5000mm, 4000mm, 3000mm, 2000mm, 1000mm, 500mm, or a range between any two.

[0103] In some embodiments, more preferably, n is an integer greater than or equal to 5 and less than or equal to 1000, and N is an integer greater than or equal to 5 and less than or equal to 1000. In some other embodiments, n is an integer greater than or equal to 10 and less than or equal to 500, and N is an integer greater than or equal to 10 and less than or equal to 500.

[0104] In some embodiments, such as Figure 6 As shown, the single-crystal silicon rod has a length direction and includes a head and a tail arranged opposite each other along the length direction. From the head to the tail, the single-crystal silicon rod is divided into S-segment silicon rod units. Each silicon rod unit includes a first end and a second end opposite each other along the length direction, with the first end near the head and the second end near the tail. The single-crystal silicon rod further satisfies: 0 ≤ |C| s-1 -C s | / C s ≤0.8; where C s C represents the hydrogen doping concentration at the second end of the s-th silicon rod unit; s-1 This represents the doping concentration of antimony at the first end of the silicon rod unit in segment s; s is an integer greater than or equal to 2. It is understood that s ≤ S.

[0105] In some embodiments, the value of S is based on the actual length of the monocrystalline silicon rod. For example, when S is 2, the monocrystalline silicon rod is divided into two segments, with the first end corresponding to the head position and the second end corresponding to the tail position in each segment.

[0106] In some embodiments, any one of the S-segment silicon rod units has the same dimensions along its length. It is understood that when the dimensions are equal, each silicon rod unit can be considered as having the same unit structure.

[0107] In some embodiments, the dimension of any one of the S-segment silicon rod units in the length direction is A mm, satisfying: 1 ≤ A ≤ 50. For example, A can be any one value or a range between any two values ​​from 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, 36 mm, 37 mm, 38 mm, 39 mm, 40 mm, 41 mm, 42 mm, 43 mm, 44 mm, 45 mm, 46 mm, 47 mm, 48 mm, 49 mm, and 50 mm. The length of a silicon rod unit is determined by the overall length of the single-crystal silicon rod and the number of segments that need to be divided.

[0108] Furthermore, the preferred dimension Amm can be in the range of 5mm to 20mm; the more preferred dimension Amm can be in the range of 10mm to 15mm.

[0109] In some embodiments, s is an integer greater than or equal to 2 and less than or equal to 3000, and S is an integer greater than or equal to 2 and less than or equal to 3000. In some other embodiments, s is an integer greater than or equal to 2 and less than or equal to 60, and S is an integer greater than or equal to 2 and less than or equal to 60. For example, taking a single-crystal silicon rod with a total length of 6000mm as an example, when it needs to be divided into 2 segments, S is 3000; when it needs to be divided into 50 segments, S is 60. Similarly, the total length of the single-crystal silicon rod can also be any one of 5000mm, 4000mm, 3000mm, 2000mm, 1000mm, 500mm, or a range between any two.

[0110] In some embodiments, more preferably, s is an integer greater than or equal to 5 and less than or equal to 1000, and S is an integer greater than or equal to 5 and less than or equal to 1000. In some other embodiments, s is an integer greater than or equal to 10 and less than or equal to 500, and S is an integer greater than or equal to 10 and less than or equal to 500.

[0111] Understandably, when a single-crystal silicon rod is divided, |C n-1 -C n | / C n Used to indicate the degree of variation in antimony doping concentration at the head and tail of the divided silicon rod units (two or more); |C s-1 -C s | / C sThis indicates the variation in hydrogen doping concentration at the head and tail of a divided silicon rod unit (two or more units). It should be noted that when 0 ≤ |C|... n-1 -C n | / C n ≤0.8 and 0≤|C s-1 -C s | / C s When the value is ≤0.8, it indicates that the difference in doping concentration of antimony and hydrogen elements in the silicon rod units arbitrarily divided in the single crystal silicon rod is small, which can further reduce the gradient change of resistivity in the single crystal silicon rod, making the resistivity change more gradual and reducing the non-uniformity of resistivity in the single crystal silicon rod.

[0112] Among them, |C n-1 -C n | / C n The value can be any one of 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or a range between any two values; |C s-1 -C s | / C s The value can be any one of 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8, or a range between any two values. Therefore, when the difference in antimony and hydrogen doping concentrations between the head and tail of each silicon rod unit is within the above range, a more uniform element distribution can be achieved, which helps to improve the uniformity of resistivity variation in the single-crystal silicon rod.

[0113] In some embodiments, the single-crystal silicon rod further satisfies: 1E+14cm -3 ≤C n ≤8E+15cm -3 For example, it could be 1E+14cm -3 2E+14cm -3 3E+14cm -3 4E+14cm -3 5E+14cm -3 6E+14cm -3 7E+14cm -3 8E+14cm -3 9E+14cm -3 1E+15cm -3 2E+15cm -3 3E+15cm -3 4E+15cm -3 5E+15cm -3 6E+15cm -3 7E+15cm -38E+15cm -3 The range between any one or any two values ​​in the range.

[0114] In some embodiments, the single-crystal silicon rod further satisfies: 1E+14cm -3 ≤C n-1 ≤8E+15cm -3 For example, it could be 1E+14cm -3 2E+14cm -3 3E+14cm -3 4E+14cm -3 5E+14cm -3 6E+14cm -3 7E+14cm -3 8E+14cm -3 9E+14cm -3 1E+15cm -3 2E+15cm -3 3E+15cm -3 4E+15cm -3 5E+15cm -3 6E+15cm -3 7E+15cm -3 8E+15cm -3 The range between any one or any two values ​​in the range.

[0115] In some embodiments, the single-crystal silicon rod further satisfies: 2E+13cm -3 ≤C s ≤1E+17cm -3 For example, it could be 2E+13cm -3 3E+13cm -3 4E+13cm -3 5E+13cm -3 8E+13cm -3 1E+14cm -3 2E+14cm -3 5E+14cm -3 8E+14cm -3 1E+15cm -3 2E+15cm -3 5E+15cm -3 8E+15cm -3 1E+16cm -3 5E+16cm -3 6E+16cm -3 7E+16cm -3 1E+17cm -3The range between any one or any two values ​​in the range.

[0116] In some embodiments, the single-crystal silicon rod further satisfies: 2E+13cm -3 ≤C s-1 ≤1E+17cm -3 For example, it could be 2E+13cm -3 3E+13cm -3 4E+13cm -3 5E+13cm -3 8E+13cm -3 1E+14cm -3 2E+14cm -3 5E+14cm -3 8E+14cm -3 1E+15cm -3 2E+15cm -3 5E+15cm -3 8E+15cm -3 1E+16cm -3 5E+16cm -3 6E+16cm -3 7E+16cm -3 1E+17cm -3 The range between any one or any two values ​​in the range.

[0117] In some embodiments, this application also provides a method for preparing a single-crystal silicon rod, characterized in that it includes:

[0118] A silicon raw material is provided, and a single crystal silicon rod is obtained through the steps of material preparation, repeated feeding, temperature stabilization, crystal pulling, shoulder formation, equal diameter formation, and finishing. In at least one of the steps of material preparation, repeated feeding, temperature stabilization, crystal pulling, shoulder formation, equal diameter formation, and finishing, hydrogen gas is introduced into the silicon raw material. Before the crystal pulling step, an antimony-containing elemental metal or alloy is added to the silicon raw material.

[0119] Before the single-crystal silicon rod is fully grown, the doping concentration during the solidification process is adjusted to control the doping ratio of hydrogen and antimony elements to meet the following requirements:

[0120] 1E-3≤C a / C b ≤4E+2;

[0121] In the formula, C a C represents the doping concentration of antimony in a single-crystal silicon rod. b denoted as the hydrogen doping concentration in a single-crystal silicon rod.

[0122] Understandably, the concentration of doped elements during the solidification process of a single-crystal silicon rod can be adjusted by regulating the time and flow rate of hydrogen gas introduced.

[0123] In some embodiments, the time for introducing hydrogen into the silicon raw material satisfies:

[0124] t 总 =t1+t2+t3+t4+t5+t6+t7, and 0.5h≤t 总 ≤82h;

[0125] Among them, t 总 The total time for introducing hydrogen is t1, which is the time for introducing hydrogen during the material preparation stage; t2 is the time for introducing hydrogen during the re-feeding stage; t3 is the time for introducing hydrogen during the temperature stabilization stage; t4 is the time for introducing hydrogen during the crystallization stage; t5 is the time for introducing hydrogen during the shoulder formation stage; t6 is the time for introducing hydrogen during the equal diameter stage; and t7 is the time for introducing hydrogen during the finishing stage.

[0126] It is understandable that the total time t for introducing hydrogen gas is... 总 This refers to the total time that hydrogen gas is introduced during the growth of each monocrystalline silicon cell into a monocrystalline silicon rod. 总 The value of (unit: h) can be any value or a range between any two of the following: 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82. By controlling the hydrogen introduction time to meet the above value range, the hydrogen doping concentration and doping uniformity can be controlled to an ideal level.

[0127] In some embodiments, the time for introducing hydrogen into the silicon raw material also satisfies:

[0128] t1: t2: t3: t4: t5: t6: t7=(0~10): (0~8): (0~2): (0~1.5): (0~3):

[0129] (0~55): (0~2).

[0130] Specifically, t1, t2, t3, t4, t5, t6, and t7 are not all 0 at the same time. For example, the ratio of t1:t2:t3:t4:t5:t6:t7 can be any value or a range between any two values ​​from 2:2:0:0:0:0:0, 0:2:1.5:1:3:50:2, 1:2:1:0:0:0:0, 0:0:1:1.5:2:55:0, and 0:8:1:1.5:3:10:1.

[0131] In some embodiments, the time for introducing hydrogen into the silicon raw material further satisfies:

[0132] t1: t2: t3: t4: t5: t6: t7= (0.00001~10): (0.00001~8): (0.00001~2):

[0133] (0.00001~1.5): (0.00001~3): (0.00001~55): (0.00001~2).

[0134] In some embodiments, it is preferable to introduce hydrogen into the silicon raw material after the refeeding step is completed.

[0135] Understandably, introducing hydrogen during the temperature stabilization stage allows it to act as a heat transfer medium, making the ambient temperature of the silicon raw material more uniform and stable. This prevents stress caused by localized overheating or undercooling due to temperature fluctuations, reducing the probability of defects in the silicon crystal. In the crystallization stage, introducing hydrogen suppresses impurity adsorption on the surface of the silicon melt, reducing the risk of impurities entering the growing crystal. During the shoulder formation stage, introducing hydrogen can regulate the undercooling of the silicon melt, allowing the crystal to grow at a specific angle and rate, obtaining crystals that meet size requirements, further reducing dislocations and crystal orientation deviations, and ensuring consistent crystal growth. In the constant diameter stage, introducing hydrogen helps maintain a stable growth environment, ensuring that the hydrogen doping concentration within the silicon crystal is radially uniform. When the time for introducing hydrogen into the silicon raw material meets the above-mentioned proportions, the doping concentration and uniformity of hydrogen in the single-crystal silicon rod can be precisely controlled, thereby reducing dislocations and crystal orientation deviations in the single-crystal silicon rod. It also makes the head-to-tail ratio of dislocations and crystal orientation deviations more likely to be 1, significantly improving the quality and production efficiency of single-crystal silicon.

[0136] In some embodiments, the method for preparing single-crystal silicon rods further includes: after the re-feeding step, introducing a protective gas into the silicon raw material;

[0137] In this mixture, hydrogen and protective gas form a gas mixture, with the volume percentage of hydrogen in the gas mixture ranging from 1% to 90%.

[0138] It is understandable that the volume percentage of hydrogen in the mixed gas can be any value or a range between any two of the following: 1%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%. The protective gas can be argon. Introducing a protective gas simultaneously with hydrogen serves two purposes: firstly, it creates a certain gas flow environment within the single crystal furnace 100, diffusing around the silicon crystal growth area and promoting stable convection, ensuring a consistent crystal growth environment and avoiding crystal defects caused by localized environmental differences; secondly, it transfers heat to areas outside the silicon crystal growth area through gas flow, thus providing cooling and helping to regulate the temperature gradient. Simultaneously, it removes impurities volatilized from the surface of the molten silicon, facilitating crystal growth along a specific direction, reducing crystal orientation deviation, and improving the overall quality of the single crystal silicon rod. When the volume percentage of hydrogen in the mixed gas meets the above-mentioned range, it ensures the growth quality of the single crystal silicon rod while performing hydrogen doping on the single crystal silicon, and avoids the risk of explosion caused by excessive hydrogen content.

[0139] In some embodiments, the volume percentage of hydrogen in the gas mixture is preferably 5% to 90%.

[0140] It is understandable that the volume percentage of hydrogen in the gas mixture can be any value or a range between any two values ​​of 5%, 15%, 25%, 35%, 45%, 55%, 65%, 75%, 85%, 90%.

[0141] In some embodiments, the volume percentage of hydrogen in the gas mixture is preferably 5% to 35%.

[0142] It is understandable that the volume percentage of hydrogen in the gas mixture can be any value of 5%, 10%, 15%, 20%, 25%, 30%, or 35%, or any range between two values. When the volume percentage of hydrogen in the gas mixture meets the above range, it can further ensure that sufficient hydrogen is used to dope the single-crystal silicon.

[0143] In some embodiments, the hydrogen flow rate is 0.0001 to 180 slpm.

[0144] It is understandable that the hydrogen flow rate (unit: slpm) can be any value or a range between any two of the following: 0.0001, 1, 30, 60, 90, 120, 150, 180.

[0145] In some embodiments, the hydrogen flow rate is preferably 5 to 50 slpm.

[0146] Understandably, the hydrogen flow rate (unit: slpm) can be any value or a range between any two of the following: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50. When the hydrogen flow rate meets the above range, the hydrogen has an ideal doping concentration in the single-crystal silicon rod, while avoiding uneven distribution caused by excessive real-time flow rate, thus ensuring good uniformity of hydrogen concentration in both the axial and radial directions of the single-crystal silicon rod.

[0147] In some embodiments, the flow rate of the protective gas is 40 to 200 slpm.

[0148] It is understandable that the flow rate of the protective gas (unit: slpm) can be any value or a range between any two of the following: 40, 60, 80, 100, 120, 140, 160, 180, 200.

[0149] In some embodiments, from the end of the re-addition step to the beginning of the equal-diameter step, the volatilization rate η of antimony is controlled to satisfy:

[0150] η=(H1 / 100mm)×100%-15%;

[0151] Where H1 is the liquid outlet distance inside the single crystal furnace 100, in mm; the volatility η satisfies: 5% ≤ η ≤ 25%; the liquid outlet distance H1 satisfies: 20mm ≤ H1 ≤ 40mm.

[0152] It is understood that the liquid gate distance H1 (unit: mm) can be any value from 20, 25, 30, 35, 40, or any range between two values. Too small a liquid gate distance H1 will lead to an increased breakage rate of the single crystal silicon rod, affecting the crystal formation quality, and will cause abnormalities such as silicon spraying and silicon adhesion. On the other hand, too large a liquid gate distance H1 will make crystal formation too difficult.

[0153] like Figure 1 and Figure 2As shown, the single crystal furnace 100 includes a flow guide tube 10 and a crucible 30. The crucible 30 contains silicon raw material, which melts into liquid silicon after the melting step. The flow guide tube 10 is positioned directly above the crucible 30 to guide the protective airflow, form a stable airflow field, regulate the temperature field, and assist in forming a temperature gradient during the preparation of the single crystal silicon rod. The liquid outlet distance H1 is the gap between the lower edge of the flow guide tube 10 and the surface of the liquid silicon 40. The liquid silicon 40 is the liquid formed after the silicon raw material is melted. On one hand, the value of the liquid outlet distance H1 affects the volatilization of doping elements and antimony. A larger liquid outlet distance results in a smaller antimony volatilization rate η, and a smaller liquid outlet distance results in a larger antimony volatilization rate η. The antimony volatilization rate η affects the doping concentration of the single crystal silicon rod during growth, thus affecting the resistivity and axial uniformity of the resistivity in the single crystal silicon rod. Therefore, by controlling the volatilization rate η and the liquid outlet distance H1 to satisfy the above relationship, it can be ensured that the volatilization rate η of antimony is always in a relatively stable state during the growth of single crystal silicon rod, thereby keeping the resistivity in the single crystal silicon rod in a stable state, and also avoiding the cost of adding antimony raw materials due to excessive volatilization of antimony.

[0154] Understandably, the volatility of Group III-V elements also affects the doping of hydrogen in the crystal. When the volatility of Group III-V elements is high, the surface tension of the silicon melt decreases, making it easier for hydrogen to form bubbles on the surface of the silicon melt and escape. This reduces the solubility of hydrogen in the silicon melt, resulting in a decrease in the amount of hydrogen doped into the crystal. Therefore, by controlling the value of the liquid outlet distance H1 to control the volatility η of Group III-V elements to an ideal range, it is also possible to further control the ideal doping concentration of hydrogen in the single-crystal silicon rod.

[0155] Understandably, the height of crucible 30 within the single-crystal furnace 100 can be adjusted in real time. During the growth of the single-crystal silicon rod, the liquid level of silicon melt 40 in crucible 30 decreases as the length of the single-crystal silicon rod increases. By real-time detection of the liquid outlet distance H1 within the single-crystal furnace 100 and adjustment of the height of crucible 30, it is ensured that the liquid outlet distance H1 remains essentially constant after the silicon raw material melts to form silicon melt 40. Maintaining an essentially constant liquid outlet distance H1 means that, during the process of maintaining the liquid outlet distance H1 by adjusting the height of crucible 30, the error between the actual liquid outlet distance H1 and the preset liquid outlet distance does not exceed ±5% (approximately ±1 to 2 mm). The height of crucible 30 can be adjusted using a screw jack or hydraulic lifting device, or assisted by an automated control system, or by other height adjustment devices, which will not be elaborated further.

[0156] The distance H1 between the liquid outlet and the infrared measuring device is detected by a CCD (Charge-Coupled Device), which can be achieved in the following way:

[0157] 1) Install the CCD infrared measurement device in a position where the liquid surface of silicon liquid 40 inside the single crystal furnace 100 can be clearly observed, such as near the observation window on the side or top of the furnace body. Ensure that the device is installed firmly and can withstand the high temperature and possible vibration of the working environment of the single crystal furnace 100, while ensuring that the optical path is not blocked by other structures or components inside the furnace.

[0158] 2) Use optical components such as infrared lenses and mirrors to construct an optical path so that the infrared radiation emitted from the surface of the silicon liquid 40 can be focused onto the CCD detector.

[0159] 3) After the material preparation is completed, the CCD detector is calibrated for temperature and space, and the signal intensity curves corresponding to the temperature and position of the silicon liquid 40 are recorded.

[0160] 4) In the steps of re-injection, crystal pulling, shoulder placement, shoulder rotation and equal diameter, the acquired infrared images are processed to calculate the height of the liquid surface through the temperature characteristics of the silicon liquid 40, and then the liquid outlet distance H1 is calculated.

[0161] By maintaining a relatively constant liquid outlet distance H1, a stable temperature field and airflow field can be formed within the single crystal furnace 100. On the one hand, this maintains a suitable temperature gradient at the solid-liquid interface, ensuring uniform temperature distribution of the silicon liquid 40 and avoiding abnormal growth and defects in the silicon crystal. On the other hand, it controls the convection of the silicon liquid 40, ensuring uniform distribution of doped elements and further improving the uniformity of doping concentration. It also enables the single crystal silicon rod to grow uniformly, reducing crystal defects and improving the overall quality of the single crystal silicon rod.

[0162] In some embodiments, the volatile rate η satisfies: 5% ≤ η ≤ 25%.

[0163] It is understandable that the volatility η can be any value or a range between any two of the following: 5%, 10%, 15%, 20%, and 25%. When the volatility η meets the above range, the doping concentration of group III-V elements and hydrogen elements during crystal rod growth can be effectively controlled, thereby ensuring that the single crystal silicon rod has uniform resistivity in the axial direction and uniform hydrogen element concentration in the radial direction.

[0164] In some embodiments, a flow guide cylinder 10 is provided inside the single crystal furnace 100. The flow guide cylinder 10 includes a first section 11 and a second section 12 connected to each other, satisfying the following:

[0165] tanα = H2 / W1, and 0 ≤ tanα ≤ 0.58;

[0166] Where α is the angle formed by the second segment 12 and the first direction X, in °; H2 is the height of the projection of the second segment 12 in the second direction, in mm; W1 is the length of the projection of the second segment 12 in the first direction, in mm; where the first direction and the second direction intersect.

[0167] Wherein, the included angle α is the angle formed by the second segment 12 and the first direction X, in degrees; H2 is the height of the projection of the second segment 12 in the second direction Y, in mm; W1 is the length of the projection of the second segment 12 in the first direction X, in mm; as Figure 1 As shown, the first direction X is horizontal, and the second direction Y is vertical, intersecting the second direction Y. In some embodiments, the first direction X and the second direction Y are perpendicular to each other.

[0168] In some embodiments, the included angle α can be the included angle formed by the line connecting the beginning and end of the second segment 12 and the first direction X.

[0169] Understandably, the first section 11 of the flow guide tube 10 forms a closed sidewall, typically a cylindrical structure, upright and surrounding the crucible 30. It provides a vertical flow channel for hydrogen and protective gases, allowing the gases to flow in a specific direction, thus ensuring stable convection near the single-crystal silicon rod and crucible 30, and ensuring a consistent crystal growth environment. The second section 12 of the flow guide tube 10 connects to the first section 11 and forms the bottom. The second section 12 extends inward from its connection with the first section 11 into the flow guide tube 10, while tilting towards the side closer to the molten silicon 40, so that the direction of extension of the second section 12 forms an angle α with the first direction X. When tanα = 0, the second section 12 is parallel to the first direction X.

[0170] In some embodiments, the value of tanα is preferably 0.0001≤tanα≤0.58, that is, the second segment 12 forms an acute angle α with the first direction X.

[0171] It is understandable that the value of tanα can be any value or a range between any two of 0.001, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.58. During the gas flow within the single-crystal furnace 100, the included angle α also affects the volatilization of dopant elements. The larger the included angle α, the lower the real-time volatilization rate of Group III-V elements, while also allowing more oxygen to enter the single-crystal silicon rod. Conversely, the smaller the included angle α, the higher the real-time volatilization rate of Group III-V elements. Therefore, controlling the value of tanα to meet the above-mentioned range ensures that both antimony and oxygen in the single-crystal silicon rod have reasonable contents.

[0172] In some embodiments, the guide tube 10 has a maximum diameter D max ,satisfy:

[0173] D max ≥2W1+W2;

[0174] The first segment 11 and the second segment 12 together form a receiving cavity 13. The end of the receiving cavity 13 near the liquid surface of the silicon liquid 40 has a through hole 14. W2 is the maximum size of the through hole 14 along the first direction X, in mm.

[0175] In some embodiments, the receiving cavity 13 has a through hole 14 at one end near the silicon liquid 40, and W2 is the maximum size of the through hole 14 in mm. It is understood that W2 is greater than or equal to the target diameter of the single crystal silicon rod.

[0176] In some embodiments, the maximum diameter D max Satisfies: 700mm≤D max ≤1200mm.

[0177] In some embodiments, the length W1 satisfies: 155mm ≤ W1 ≤ 455mm.

[0178] In some embodiments, the maximum dimension W2 satisfies: 290mm≤W2≤390mm.

[0179] In some embodiments, the height H2 satisfies: 0 ≤ H2 ≤ 300 mm.

[0180] It is understandable that the maximum diameter D max The values ​​(in mm) of _____ can be any value or any two values ​​between 700, 800, 900, 1000, 1100, and 1200; the values ​​(in mm) of length W1 can be any value or any two values ​​between 155, 200, 250, 300, 350, 400, and 455; the values ​​(in mm) of maximum dimension W2 can be any value or any two values ​​between 290, 310, 330, 350, 370, and 390; the values ​​(in mm) of height H2 can be any value or any two values ​​between 0, 50, 100, 150, 200, 250, and 300. When W1, W2, H2, and D _____, the maximum dimension W2 can be any value or any two values ​​between 290, 310, 330, 350, 370, and 390. max When the above value range is met, the volume Vs of the gas flow region can be within the ideal range, thereby further optimizing the guiding effect of the guide tube 10 in the growth process of single crystal silicon rod, so that the resistivity, oxygen content and hydrogen content of the prepared single crystal silicon rod have ideal uniformity.

[0181] It is understandable that when the first section 11 of the guide tube 10 is enclosed to form a cylindrical structure, the diameter of the guide tube 10 can gradually decrease along the vertical direction toward the crucible 30, or it can remain unchanged, controlling the maximum diameter D. maxBy satisfying the above relationships, the flow direction and speed of the protective gas in the single crystal furnace 100 can be further adjusted, thereby improving the stability of the single crystal silicon rod crystal structure during the crystal pulling process.

[0182] In some embodiments, the single crystal furnace 100 includes a top cover 20, the top cover 20 is provided with a first vent 21 and a second vent 22, the first vent 21 is arranged around the second vent 22, the first vent 21 is used to introduce hydrogen into the single crystal furnace 100, and the second vent 22 is used to introduce protective gas into the single crystal furnace 100.

[0183] Among them, such as Figure 1 As shown, the first vent 21 and the center of the top cover 20 have a first distance D1, and the second vent 22 has a diameter D2, satisfying:

[0184] 2D1>D2.

[0185] like Figures 1-3 As shown, the second vent 22 is a channel penetrating the top cover 20, and there are several first vents 21, which are arranged around the outer periphery of the second vent 22; the number of first vents 21 is preferably 8 to 10. During the crystal pulling process, hydrogen gas enters the guide tube 10 through the first vent 21 and comes into contact with the silicon liquid 40 in the crucible 30 to achieve doping. The protective gas enters the guide tube 10 through the second vent 22 and flows in the area inside and outside the guide tube 10 to protect the single crystal silicon rod. It can be understood that the protective gas can be directly introduced into the guide tube 10 through the second vent 22, or it can be introduced through a device such as a furnace tube, and then flow through the second vent 22 into the guide tube 10. When the first spacing D1 and the diameter D2 of the second vent satisfy 2D1>D2, the hydrogen gas can have a large flow space in the guide tube 10 and mix thoroughly and evenly with the protective gas, thereby improving the uniformity of the doping process.

[0186] In some embodiments, the first spacing D1 satisfies: 350mm≤D1≤500mm.

[0187] In some embodiments, the diameter D2 of the second vent 22 satisfies: 500mm≤D2≤800mm.

[0188] It is understood that the value of the first spacing D1 (unit: mm) can be any value or a range between any two of 350, 380, 410, 440, 470, and 500. The value of the diameter D2 of the second vent 22 (unit: mm) can be any value or a range between any two of 500, 550, 600, 650, 700, 750, and 800.

[0189] In some embodiments, a guide tube 10 is provided inside the single crystal furnace 100, and the guide tube 10 has a maximum diameter D.max Satisfying: D max ≥2D1;

[0190] The bottom of the guide tube 10 and the top cover 20 have a third distance H3, which satisfies: 0.5m≤H3≤1.5m.

[0191] It is understandable that the value of the third spacing H3 (unit: m) can be any value among 0.5, 0.7, 0.9, 1.1, 1.3, and 1.5, or a range between any two values.

[0192] Based on the above embodiments, such as Figure 4 As shown in the shaded area, the first segment 11 and the second segment 12 enclose a receiving cavity 13, within which a first gas flow region 50 is provided. A second gas flow region 60 is provided between the outer wall of the guide tube 10 and the inner wall of the single crystal furnace 100, and between the growing single crystal silicon rod and the inner wall of the single crystal furnace 100. It is understood that the second gas flow region 60 is located within the single crystal furnace 100, and the gas flow region is above the surface of the silicon melt 40. Furthermore, the second gas flow region 60 surrounds the guide tube 10 (and also surrounds the growing single crystal silicon rod). It is understood that the second gas flow region 60 includes a first region 61 and a second region 62, wherein the first region 61 is the region for gas flow between the guide tube 10 and the inner wall of the single crystal furnace 100, and the second region 62 is the region for gas flow located above the surface of the silicon melt 40 and after deducting the volume of the single crystal silicon itself.

[0193] In some embodiments, the volume Vs of the second gas flow region 60 satisfies: Vs = V1 + V2. Wherein, V1 is the first volume of the first region 61, and V2 is the second volume of the second region 62.

[0194] It is understandable that the value of the first volume V1 of the first region 61 is affected by the maximum diameter D of the included angle. max Influenced by the third spacing H3, the value of the second volume V2 of the second region 62 is affected by the orifice distance H1 and the maximum diameter D. max The influence of the first volume V1 and the second volume V2 can be adjusted to change the flow direction and speed of the protective gas in the single crystal furnace 100, so that the gas is split after reaching the crystal growth interface. Therefore, the volume Vs of the second gas flow region 60 can be controlled to have a reasonable size, which can adjust the blowing force of the protective gas on the growth interface of the single crystal silicon rod and improve the stability of the crystal structure of the single crystal silicon rod during the crystal pulling process.

[0195] This application also provides a silicon wafer prepared from a single-crystal silicon rod as described in any of the above embodiments; the silicon wafer contains antimony and hydrogen; wherein the concentration of antimony is 1E+14cm⁻¹. -3 Up to 8E+15cm-3 The concentration of hydrogen is 2E+13cm. -3 Up to 1E+17cm -3 .

[0196] In some embodiments, the concentration of antimony is 2E+14cm⁻¹. -3 Up to 7E+15cm -3 The concentration of hydrogen is 1E+15cm. -3 Up to 7E+16cm -3 .

[0197] In some embodiments, the concentration of antimony is 1E+15cm⁻¹. -3 Up to 7E+15cm -3 The concentration of hydrogen is 3E+15cm. -3 Up to 6E+16cm -3 .

[0198] In some embodiments, the resistivity of the single-crystal silicon rod is ρΩ·cm, satisfying: 0.1≤ρ≤7. For example, ρΩ·cm can be any one value or a range between any two values ​​selected from 0.1Ω·cm, 0.2Ω·cm, 0.3Ω·cm, 0.4Ω·cm, 0.5Ω·cm, 0.8Ω·cm, 1Ω·cm, 1.5Ω·cm, 2Ω·cm, 2.5Ω·cm, 3Ω·cm, 3.5Ω·cm, 4Ω·cm, 4.5Ω·cm, 5Ω·cm, 5.5Ω·cm, 6Ω·cm, 6.5Ω·cm, and 7Ω·cm.

[0199] In some embodiments, the resistivity of the single-crystal silicon rod is ρΩ·cm, satisfying: 0.4≤ρ≤1.5.

[0200] In some embodiments, the resistivity of the single-crystal silicon rod is ρΩ·cm, satisfying: 0.6≤ρ≤1.5.

[0201] In some embodiments, the resistivity of the single-crystal silicon rod is ρΩ·cm, satisfying: 0.8≤ρ≤1.4.

[0202] In some embodiments, this embodiment also provides a silicon wafer, which is prepared from a single-crystal silicon rod. The silicon wafer contains antimony and hydrogen; the concentration of antimony is 1E+14cm⁻¹. -3 Up to 8E+15cm -3 The concentration of hydrogen is 2E+13cm. -3 Up to 1E+17cm -3 .

[0203] In some embodiments, the concentration of antimony in the silicon wafer is 2E+14cm⁻¹. -3 Up to 7E+15cm -3The concentration of hydrogen is 1E+15cm. -3 Up to 7E+16cm -3 .

[0204] In some embodiments, the concentration of antimony in the silicon wafer is 1E+15cm⁻¹. -3 Up to 7E+15cm -3 The concentration of hydrogen is 3E+15cm. -3 Up to 6E+16cm -3 .

[0205] In some embodiments, the thickness of the silicon wafer is 70–150 μm.

[0206] In some embodiments, the silicon wafer is circular, and the diameter of the silicon wafer is 223–330 mm.

[0207] In some embodiments, this application also provides a method for preparing a single-crystal silicon rod, comprising:

[0208] Silicon-containing raw materials are prepared and placed in a single crystal furnace 100;

[0209] Then, the following steps are performed sequentially: material preparation, re-addition, welding, temperature stabilization, crystal pulling, shoulder expansion, shoulder rotation, and equal diameter measurement to obtain a single crystal silicon rod.

[0210] Hydrogen gas is introduced in at least one of the following steps: material preparation, re-addition, welding, temperature stabilization, crystal pulling, shoulder expansion, shoulder rotation, and equalization; and

[0211] In at least one of the following steps: chemical processing, re-injection, welding, temperature stabilization, crystal introduction, shoulder expansion, shoulder rotation, and equal diameter, an elemental metal or alloy containing antimony is introduced.

[0212] In some embodiments, the silicon-containing raw materials include virgin polycrystalline silicon or a combination of recycled materials. The raw materials can be polycrystalline or granular, or they can be fed in proportion to 20%-80% recycled materials.

[0213] In some embodiments, the melting process is specifically carried out using a heater to melt solid silicon into liquid silicon. Before melting, the single crystal furnace 100 is evacuated and leak-checked to ensure the airtightness of the furnace during the crystal pulling process, allowing the single crystal pulling process to proceed smoothly. The melting stage includes the initial melting stage, the middle melting stage, and the later melting stage. When the heater heats the crucible 30, the edge of the crucible 30 is closer to the thermal field and has a higher temperature, while the center of the crucible 30 has a lower temperature. The edge of the crucible 30 melts first, followed by the center and top. Therefore, by controlling the melting power, the rotation speed of the crucible 30, the inert gas flow rate, the hydrogen flow rate, and the pressure inside the single crystal furnace 100, the edge of the crucible 30 is melted first, and the center is melted last, so as to remove impurities and unmelted materials from the crucible 30. The initial crystallization stage involves: a crystallization power of 30-150 kW, a quartz crucible rotation speed of 1-5 r / min, an inert gas flow rate of 40-120 slpm, a hydrogen flow rate of 40-120 slpm, a pressure of 5-30 torr inside the single crystal furnace, and a crystallization time of 1-5 hours. The intermediate crystallization stage involves: a crystallization power of 50-150 kW, a quartz crucible rotation speed of 1-5 r / min, and an inert gas flow rate of 4... The initial reaction time is 0-120 slpm, with a hydrogen flow rate of 40-120 slpm, a pressure of 5-30 torr inside the single crystal furnace 100, and a reaction time of 5-15 hours. In the later stages of reaction: the rotation speed of the quartz crucible 30 is 1-12 r / min, the pressure inside the single crystal furnace 100 is 5-30 torr, the inert gas flow rate is 40-120 slpm, the hydrogen flow rate is 40-120 slpm, and the heater power is 50-150 kW. Inert protective gas is introduced throughout the reaction process; the flow of inert gas helps to remove some impurities and reaction product gases.

[0214] In some embodiments, refeeding refers to using a refeeder to replenish the material to meet the load-bearing requirements of the quartz crucible 30, such as simultaneous doping of conventional alloys. After refeeding, an antimony-containing elemental metal or alloy can be introduced into the silicon material. Specifically, after the refeeding is completed and before the seed crystal is fused, the antimony-containing metal or alloy is placed in the doping spoon and then placed into the molten silicon 40 after the material is melted and before the seed crystal is fused.

[0215] In some embodiments, fusion welding refers to the process of slowly lowering a seed crystal into the molten silicon surface before crystal growth begins, bringing the seed crystal temperature close to the molten silicon temperature, and then allowing the seed crystal to come into contact with the molten silicon. This process is commonly referred to as "seed crystal lowering." After the seed crystal is lowered, it fuses with the molten silicon. Once the surface temperature reaches the requirements for single crystal growth, the surface temperature and the seed crystal lifting speed can be controlled to achieve single crystal growth. The power of the main heater is adjusted to bring the molten silicon temperature in the furnace to 1460 degrees Celsius, and the seed crystal is manually lowered into the molten silicon to melt it, reaching a molten state.

[0216] In some embodiments, during the temperature stabilization stage, the rotation speed of the quartz crucible 30 is 4-12 r / min, the pressure inside the single crystal furnace 100 is 5-30 torr, the flow rate of the inert gas is 40-120 slpm, the flow rate of the hydrogen gas is 40-120 slpm, and the heater power is 30-150 kW. The silicon solution is stabilized at a temperature of 1430-1470°C to facilitate the subsequent crystal pulling process.

[0217] In some embodiments, crystal pulling is a process of effectively eliminating dislocations by adjusting the pulling speed within a suitable range for crystal formation. Antimony-containing elemental metals or alloys can be added during the crystal pulling process. During the crystal pulling stage, the rotation speed of the quartz crucible 30 is 4-12 r / min, the pressure inside the single crystal furnace 100 is 5-30 torr, the flow rate of inert gas is 40-120 slpm, the flow rate of hydrogen is 40-120 slpm, the heater power is 30-150 kW, and the seed crystal rotation speed is 0.5-20 r / min, selected according to actual needs. After preheating the seed crystal, welding and crystal pulling are performed. The average pulling speed during the crystal pulling process is 1-10 mm / min.

[0218] In some embodiments, shoulder formation is the stage of enlarging the diameter of the fine crystals to the required diameter specification; shoulder rotation is the stage of controlling the single crystal production direction from horizontal to vertical, stabilizing the diameter value. In both the shoulder formation and shoulder rotation stages, the shoulder pulling speed is 0.5-10 mm / min, and the seed crystal rotation speed is 0.5-20 r / min. That is, in the shoulder formation stage, the shoulder pulling speed is 0.5-10 mm / min, and the seed crystal rotation speed is 0.5-20 r / min; in the shoulder rotation stage, the shoulder pulling speed is 0.5-10 mm / min, and the seed crystal rotation speed is 0.5-20 r / min, selected according to actual needs.

[0219] In some embodiments, the constant diameter stage is a fully automated control stage for single crystal growth. Different parameters are set within different length ranges of constant diameter based on the effect of antimony volatilization. After the bract is broken, dopant is replenished according to the refeeding process. During the constant diameter growth stage, the rotation speed of the quartz crucible 30 is 4-12 r / min, the pressure inside the single crystal furnace 100 is 5-30 torr, the flow rate of inert gas is 40-120 slpm, the flow rate of hydrogen is 40-120 slpm, the heater power is 30-150 kW, and the seed crystal rotation speed is 0.5-20 r / min.

[0220] In some embodiments, a protective gas is introduced in any one of the steps of material preparation, re-injection, welding, temperature stabilization, crystal pulling, shoulder expansion, shoulder rotation, and equalization; wherein the volume ratio of hydrogen to protective gas is (3-80):100. For example, it can be any one of 3:100, 4:100, 5:100, 8:100, 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, 45:100, 50:100, 55:100, 60:100, 65:100, 70:100, 75:100, and 80:100.

[0221] In some embodiments, the hydrogen flow rate is 40–120 slpm. In some other embodiments, the hydrogen flow rate ranges from 60–120 slpm. In some other embodiments, the hydrogen flow rate ranges from 80–120 slpm. In some other embodiments, the hydrogen flow rate ranges from 100–120 slpm.

[0222] In some embodiments, the flow rate of the protective gas is 40–120 slpm. In some other embodiments, the flow rate ranges from 60–120 slpm. In some other embodiments, the flow rate ranges from 80–120 slpm. In some other embodiments, the flow rate ranges from 100–120 slpm. The protective gas is selected from inert gases such as argon and helium.

[0223] In some embodiments, the mass ratio of silicon-containing raw material to antimony-containing elemental metal or alloy is 100:(0.002-0.15). For example, it can be any ratio among 100:0.002, 100:0.005, 100:0.001, 100:0.005, 100:0.008, 100:0.01, 100:0.05, 100:0.1, 100:0.12, and 100:0.15.

[0224] In some embodiments, the furnace pressure of the single crystal furnace 100 is 5 to 30 torr. More preferably, the furnace pressure of the single crystal furnace 100 is 5 to 20 torr. More preferably, the furnace pressure of the single crystal furnace 100 is 5 to 15 torr.

[0225] In some embodiments, the temperature of the single crystal furnace 100 is 1400–1700°C. For example, it can be any one or a range between any two of 1400°C, 1450°C, 1500°C, 1550°C, 1600°C, 1650°C, and 1700°C.

[0226] Example 1

[0227] Polycrystalline silicon blocks or recycled materials are loaded into the quartz crucible 30. For example, solid silicon raw materials are first piled into the quartz crucible 30, and then the quartz crucible 30 filled with silicon material is placed into the single crystal furnace 100.

[0228] The single crystal furnace 100 is evacuated, and the solid silicon in the quartz crucible 30 is gradually melted into a molten state by using a bottom heater and a main heater with a power of 90KW.

[0229] Because the solid silicon material in the quartz crucible 30 is stacked and melted by heating, the actual volume occupied in the quartz crucible 30 is reduced. The melted silicon material does not reach the maximum loading capacity of the quartz crucible 30. Therefore, it is necessary to fill the quartz crucible 30 with silicon material a second time through a refiller. During the filling process, the heater simultaneously melts the silicon material in the quartz crucible 30.

[0230] After the re-addition is completed, antimony (Sb) dopant is loaded into the doping spoon pre-installed in the single crystal furnace 100. Once the silicon material in the quartz crucible 30 has completely melted, the process switches to temperature control. Before the seed crystal is lowered and fused, the Sb dopant in the doping spoon is poured into the molten silicon 40, and the seed crystal is inserted into the liquid surface. Power parameters are controlled to reach the critical crystallization temperature at the liquid surface. The doping amount is calculated based on the target resistivity. Taking a full crucible of 1000 kg as an example, a single addition of primary polycrystalline silicon involves 20 g of antimony (Sb) dopant.

[0231] After the seed crystal and the liquid surface reach the crystallization temperature point, the seed crystal is pulled upwards. By adjusting parameters such as power and pulling speed, the actual single crystal diameter is placed within the range of 275-285mm for round rod diameter. After the shoulder is formed, the silicon rod equalization process is entered through the shoulder rotation process.

[0232] During the equal diameter process, the furnace pressure is adjusted to 8-15 torr, the gas flow rate to 100 slpm, the crystal rotation to 9-6 rpm, and the crucible rotation to 6-9 rpm. The power (50KW) is adjusted to control the volatilization of antimony. Once the equal diameter length is 4800mm, the silicon rod pulling is completed by finishing the process.

[0233] In addition to the other processes of the equal diameter process, in order to reduce the volatilization of antimony, the main method is to use a large furnace pressure to suppress the volatilization of antimony, with the furnace pressure between 15-30 torr.

[0234] Each of the above stages requires the introduction of hydrogen and protective argon gas, with a hydrogen / argon volume ratio of 50%; the hydrogen flow rate is 100 slpm and the argon flow rate is 120 slpm.

[0235] Examples 2-8

[0236] The specific preparation process is the same as in Example 1, except that the concentrations of antimony and hydrogen doping are different.

[0237] Comparative Examples 1-3

[0238] The specific preparation process is the same as in Example 1, except that hydrogen gas is not introduced and only antimony element is used for doping.

[0239] The specific elemental doping concentrations and test performance of Examples 1-5 and Comparative Examples 1-2 are shown in Table 1.

[0240] Among them, C a and C b The measurement was obtained directly from a 3000mm section of a single-crystal silicon rod; C a1 C a2 C b1 C b2 The measurements were taken from 10mm areas at the head and 10mm areas at the tail.

[0241] In Table 1, the head and tail refer to the positions 10mm from both ends of the monocrystalline silicon rod in the length direction, and the middle part refers to the position 3000mm from the end of the monocrystalline silicon rod.

[0242] Resistivity (Ω·cm) test: The resistivity of the crystal rod was tested using a KDY~1A resistivity tester.

[0243] The oxygen content (ppma) test method is as follows: oxygen content is measured at the tip of the crystal rod. The test method is in accordance with GB / T 1557~2018. The oxygen content in the crystal rod is tested using a Nicolet 6700 Fourier transform infrared spectrometer.

[0244] Minority carrier lifetime (μs) test: The minority carrier lifetime of the crystal rod was tested using a Sinton BLS-1 minority carrier lifetime tester.

[0245] Table 1

[0246]

[0247]

[0248] Furthermore, the single-crystal silicon rods obtained in Examples 6-8 and Comparative Example 3 were divided into four segments (N=4) of silicon rod units, each segment having the same size of 10 mm. The second and fourth segments were tested, and the specific characterization parameters are shown in Table 2. In Table 2, C1 represents the antimony doping concentration at the first end (head) of the second segment, C2 represents the antimony doping concentration at the second end (tail) of the second segment, C3 represents the antimony doping concentration at the first end (head) of the fourth segment, and C4 represents the antimony doping concentration at the second end (tail) of the fourth segment; C5 represents the hydrogen doping concentration at the first end (head) of the second segment, C6 represents the hydrogen doping concentration at the second end (tail) of the second segment, C7 represents the hydrogen doping concentration at the first end (head) of the fourth segment, and C4 represents the hydrogen doping concentration at the second end (tail) of the fourth segment.

[0249] Table 2

[0250]

[0251]

[0252] As shown in Tables 1 and 2, doping Czochralski silicon single crystals with specific concentrations of hydrogen and antimony can improve the effective segregation coefficient of antimony in crystalline silicon, resulting in a more uniform distribution of antimony in the single-crystal silicon rod. In Examples 1-5, 1E-3≤C is satisfied. a / C b Within the range of ≤4E+2, the uniform distribution of antimony and hydrogen can improve the uniformity of resistivity variation in single-crystal silicon rods. Therefore, Examples 1-5 have more uniform resistivity, lower oxygen content, and longer minority carrier lifetime compared to Examples 1-2. In Examples 6-8, the silicon rod units in different segments satisfy 0≤|C n-1 -C n | / C n ≤0.8 and 0≤|C s-1 -C s | / C s Within the range of ≤0.8, the difference in doping concentration between antimony and hydrogen elements in the silicon rod unit is relatively small, which can further reduce the gradient change in resistivity in the monocrystalline silicon rod, improve the oxygen content and lifespan of the monocrystalline silicon rod, and achieve precise resistivity control. This makes the resistivity of the monocrystalline silicon rod and its derivatives more uniform and concentrated, and can effectively improve the performance and production efficiency of Czochralski silicon monocrystalline silicon and cells.

[0253] The single-crystal silicon rods and their preparation methods, as well as silicon wafers, provided in the embodiments of this application have been described in detail above. Specific examples have been used in this application to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A single-crystal silicon rod, characterized in that, The single-crystal silicon rod contains antimony and hydrogen, and the antimony doping concentration in the single-crystal silicon rod is C. a The hydrogen doping concentration in the single-crystal silicon rod is C. b The following condition is satisfied: 1E-3≤C a / C b ≤4E+2, preferably 2.5E-1≤C a / C b ≤3.5E+2.

2. A single-crystal silicon rod according to claim 1, characterized in that, The antimony doping concentration C in the single-crystal silicon rod a Satisfy: 1E+14cm -3 ≤C a ≤8E+15cm -3 ;or, The antimony doping concentration C in the single-crystal silicon rod a Satisfies: 2E+14cm -3 ≤C a ≤7E+15cm -3 ;or, The antimony doping concentration C in the single-crystal silicon rod a Satisfy: 1E+15cm -3 ≤C a ≤7E+15cm -3 .

3. A single-crystal silicon rod according to claim 1, characterized in that, The hydrogen doping concentration C in the single-crystal silicon rod b Satisfy: 2E+13cm -3 ≤C b ≤1E+17cm -3 ; or, The hydrogen doping concentration C in the single-crystal silicon rod b Satisfy: 1E+15cm -3 ≤C b ≤7E+16cm -3 ;or, The hydrogen doping concentration C in the single-crystal silicon rod b Satisfying: 3E+15cm -3 ≤C b ≤6E+16cm -3 .

4. A single-crystal silicon rod according to claim 1, characterized in that, The single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail that are disposed opposite to each other along the length direction. The antimony doping concentration at the head is C. a1 The antimony element has a doping concentration of C at the tail. a2 Satisfying: 0≤|C a1 -C a2 | / C a2 ≤0.

8.

5. A single-crystal silicon rod according to claim 4, characterized in that, The single-crystal silicon rod has a length direction, and the single-crystal silicon rod includes a head and a tail that are arranged opposite to each other along the length direction. The hydrogen doping concentration at the head is C. b1 The hydrogen doping concentration at the tail is C. b2 Satisfying: 0≤|C b1 -C b2 | / C b2 ≤0.

8.

6. A single-crystal silicon rod according to claim 5, characterized in that, The antimony element doping concentration C in the head a1 Satisfies: 2E+14cm -3 ≤C a1 ≤8E+15cm -3 ;or, The doping concentration of antimony in the tail is C a2 Satisfy: 1E+14cm -3 ≤C a2 ≤7E+15cm -3 ;or, The hydrogen doping concentration C in the head b1 Satisfy: 2E+13cm -3 ≤C b1 ≤1E+17cm -3 ;or, The hydrogen doping concentration C at the tail b2 Satisfy: 2E+13cm -3 ≤C b1 ≤1E+17cm -3 .

7. A single-crystal silicon rod according to claim 1, characterized in that, The single-crystal silicon rod has a length direction and includes a head and a tail disposed opposite to each other along the length direction. From the head to the tail, the single-crystal silicon rod is divided into N silicon rod units. Each silicon rod unit includes a first end and a second end disposed opposite to each other along the length direction, the first end being near the head and the second end being near the tail. The single-crystal silicon rod further satisfies: 0 ≤ |C| n-1 -C n | / C n ≤0.8; Among them, C n C represents the doping concentration of antimony at the second end of the nth silicon rod unit; n-1 This represents the doping concentration of antimony at the first end of the silicon rod unit in the nth segment; n is an integer greater than or equal to 2.

8. A single-crystal silicon rod according to claim 7, characterized in that, The single-crystal silicon rod has a length direction and includes a head and a tail disposed opposite to each other along the length direction. From the head to the tail, the single-crystal silicon rod is divided into S-segment silicon rod units. Each silicon rod unit includes a first end and a second end disposed opposite to each other along the length direction, the first end being near the head and the second end being near the tail. The single-crystal silicon rod further satisfies: 0 ≤ |C| s-1 -C s | / C s ≤0.8; Among them, C s C represents the hydrogen doping concentration at the second end of the s-th silicon rod unit; s-1 This represents the doping concentration of antimony at the first end of the silicon rod unit in the s-th segment; n is an integer greater than or equal to 2.

9. A single-crystal silicon rod according to claim 8, characterized in that, Any one of the n silicon rod units has the same dimension along its length; and / or, The dimension of any one of the n silicon rod units in the length direction is A mm, satisfying: 1 ≤ A ≤ 50; and / or, The n is an integer greater than or equal to 2 and less than or equal to 3000.

10. A single-crystal silicon rod according to claim 8, characterized in that, The single-crystal silicon rod satisfies at least one of the following characteristics: 1)1E+14cm -3 ≤C n ≤8E+15cm -3 ; 2)1E+14cm -3 ≤C n-1 ≤8E+15cm -3 ; 3) 2E+13cm -3 ≤C s ≤1E+17cm -3 ; 4)2E+13cm -3 ≤C s-1 ≤1E+17cm -3 。 11. A method for preparing a single-crystal silicon rod, characterized in that, include: A silicon raw material is provided, and a single crystal silicon rod is obtained through the steps of material preparation, repeated feeding, temperature stabilization, crystal pulling, shoulder formation, equal diameter formation, and finishing. In at least one of the steps of material preparation, repeated feeding, temperature stabilization, crystal pulling, shoulder formation, equal diameter formation, and finishing, hydrogen gas is introduced into the silicon raw material. Before the crystal pulling step, an antimony-containing elemental metal or alloy is added to the silicon raw material. Specifically, before the single-crystal silicon rod is fully grown, the doping concentration during the solidification process of the single-crystal silicon rod is adjusted to control the doping ratio of hydrogen and antimony to meet the following requirements: 1E-3≤C a / C b ≤4E+2; In the formula, C a C represents the doping concentration of the antimony element in the single-crystal silicon rod. b The hydrogen doping concentration in the single-crystal silicon rod is given.

12. The method for preparing a single-crystal silicon rod according to claim 11, characterized in that, The time required to introduce hydrogen gas into the silicon raw material satisfies the following: t 总 =t1+t2+t3+t4+t5+t6+t7, and 0.5h≤t 总 ≤82h; Among them, t 总 The total time for introducing hydrogen is t1, which is the time for introducing hydrogen during the material preparation stage; t2 is the time for introducing hydrogen during the re-feeding stage; t3 is the time for introducing hydrogen during the temperature stabilization stage; t4 is the time for introducing hydrogen during the crystallization stage; t5 is the time for introducing hydrogen during the shoulder formation stage; t6 is the time for introducing hydrogen during the equal diameter stage; and t7 is the time for introducing hydrogen during the finishing stage.

13. The method for preparing a single-crystal silicon rod according to claim 12, characterized in that, The time for introducing hydrogen gas into the silicon raw material also satisfies: t1: t2: t3: t4: t5: t6: t7=(0~10): (0~8): (0~2): (0~1.5): (0~3): (0～55)：(0～2)。 14. The method for preparing a single-crystal silicon rod according to claim 11, characterized in that, Also includes: After the re-feeding step, a protective gas is introduced into the silicon raw material; Wherein, the hydrogen gas and the protective gas form a mixed gas, and the volume percentage of the hydrogen gas in the mixed gas is 1-90%, preferably 5-90%; or, The flow rate of the hydrogen gas is 0.0001–180 slpm; or, The flow rate of the protective gas is 40–200 slpm.

15. The method for preparing a single-crystal silicon rod according to claim 11, characterized in that, Before the end of the re-addition step and the beginning of the equal diameter step, the volatilization rate η of the antimony element is controlled to satisfy: η=(H1 / 100mm)×100%-15%; Wherein, H1 is the liquid outlet distance in the single crystal furnace, in mm; the volatility η satisfies: 5% ≤ η ≤ 25%; the liquid outlet distance H1 satisfies: 20mm ≤ H1 ≤ 40mm.

16. The method for preparing a single-crystal silicon rod according to claim 15, characterized in that, The single crystal furnace is equipped with a flow guide tube, which includes a first section and a second section connected to each other, satisfying the following: tanα = H2 / W1, and 0 ≤ tanα ≤ 0.58; Where α is the angle formed by the second segment and the first direction, in °; H2 is the height of the projection of the second segment in the second direction, in mm; W1 is the length of the projection of the second segment in the first direction, in mm; and the first direction and the second direction intersect.

17. The method for preparing a single-crystal silicon rod according to claim 16, characterized in that, The guide tube has a maximum diameter D max ,satisfy: D max ≥2W1+W2; The first segment and the second segment together form a receiving cavity. The end of the receiving cavity near the liquid surface of the molten silicon has a through hole. W2 is the maximum size of the through hole along the first direction, in mm.

18. A silicon wafer, characterized in that, The silicon wafer is prepared from a single-crystal silicon rod as described in any one of claims 1-10 or from a single-crystal silicon rod prepared by the preparation method described in any one of claims 11-17; the silicon wafer contains antimony and hydrogen; wherein the concentration of antimony is 1E+14cm⁻¹. -3 Up to 8E+15cm -3 The concentration of hydrogen is 2E+13cm. -3 Up to 1E+17cm -3 ;or, The concentration of antimony is 2E+14cm. -3 Up to 7E+15cm -3 The concentration of hydrogen is 1E+15cm. -3 Up to 7E+16cm -3 ;or, The concentration of antimony is 1E+15cm. -3 Up to 7E+15cm -3 The concentration of hydrogen is 3E+15cm. -3 Up to 6E+16cm -3 .

19. A solar cell, characterized in that, Includes a silicon substrate, said silicon substrate being prepared from the silicon wafer of claim 18; The resistivity of the silicon substrate is 0.5-3 Ω·cm, and the thickness is 120-160 μm.

20. A solar cell according to claim 19, characterized in that, The silicon substrate includes a doped region, wherein hydrogen and antimony elements are doped into the doped region. The hydrogen concentration in the doped region is 2E+13cm⁻¹ -3 ~1E+17cm -3 ; The antimony concentration in the doped region is 1E+14cm⁻¹ -3 ~8E+15cm -3 .

Images