Preparation method for monocrystalline silicon and monocrystalline silicon

Abstract

A preparation method for monocrystalline silicon and monocrystalline silicon. The preparation method comprises: pulling a crystal bar, wherein the crystal bar grows upwards from a silicon melt; and applying a magnetic field to the silicon melt, wherein in the growth direction of the crystal bar, the magnetic field has a zero magnetic field plane, and a first distance H1 is formed between the zero magnetic field plane and the liquid level of the silicon melt, and satisfies: 0≤H1≤60 mm. In the monocrystalline silicon growth process, the distance between the magnetic field and the silicon melt is controlled, and the oxygen content of the prepared monocrystalline silicon is controlled to be 0.5×1017 atoms / cm3-3.0×1017 atoms / cm3.

Description

A method for preparing single crystal silicon and single crystal silicon

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 21, 2023, with application number 202311230049.1 and invention name “A method for preparing single crystal silicon and single crystal silicon”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the field of single crystal growth technology, and specifically relates to a method for preparing single crystal silicon and single crystal silicon. Background Art

[0003] IGBT devices require silicon wafers with minimal oxygen concentration. This is because during the IGBT manufacturing process, silicon wafers undergo heat treatments involving high-temperature diffusion at approximately 900°C and sintering at approximately 750°C. Oversaturated interstitial oxygen can segregate and precipitate within the silicon crystal, forming oxygen donors, oxygen precipitates, and secondary defects, adversely affecting the device. The generation of oxygen donors leads to a decrease in the resistivity of N-type IGBTs and poor device resistivity stability. Furthermore, IGBT silicon wafers must be free of crystal defects, preventing defects caused by oxygen precipitation during the thermal treatment of the device manufacturing process. Technical issues

[0004] During the IGBT manufacturing process, oxygen donors, oxygen precipitates, and secondary defects are formed. Oxygen donors cause a decrease in the resistivity of N-type IGBTs, resulting in poor device resistivity stability. Furthermore, if void defects (COP defects) in the silicon wafer enter the gate oxide film (GOI) of the IGBT device, they can degrade the GOI characteristics and damage the insulation of the gate oxide film. Technical Solutions

[0005] An embodiment of the present application provides a method for preparing single crystal silicon, including: pulling a crystal rod, the crystal rod growing upward from a silicon melt; applying a magnetic field to the silicon melt, the magnetic field having a zero magnetic field plane along the growth direction of the crystal rod, and a first distance H1 between the zero magnetic field plane and the liquid surface of the silicon melt, satisfying: 0≤H1≤60mm.

[0006] In some embodiments, a heat shield is provided on the periphery of the crystal ingot, and along the growth direction of the crystal ingot, a second distance H2 is present between the heat shield and the liquid surface of the silicon melt, satisfying: 15 mm ≤ H2 ≤ 35 mm.

[0007] In some embodiments, a water cooling screen is provided on the periphery of the crystal rod, and along the growth direction of the crystal rod, a third distance H3 is present between the water cooling screen and the liquid surface of the silicon melt, satisfying: 300 mm ≤ H3 ≤ 600 mm.

[0008] In some embodiments, the magnetic field has a field strength ranging from 700 GS to 1100 GS.

[0009] In some embodiments, during the step of pulling the crystal rod, the rotation speed of the crystal rod is in a range of 8 rpm to 15 rpm.

[0010] In some embodiments, in the step of pulling the crystal rod, the pulling rate of the crystal rod is in the range of 0.3 mm / min to 0.5 mm / min.

[0011] In some embodiments, during the crystal rod pulling step, the crystal rod is placed in a purge atmosphere, and the pressure range of the purge atmosphere is 1600Pa to 2500Pa.

[0012] In some embodiments, the purge atmosphere includes argon.

[0013] In some embodiments, the oxygen content of the crystal rod is in the range of 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 .

[0014] In some embodiments, the silicon melt is in a crucible, and the crucible rotates at a speed ranging from 0.5 rpm to 4 rpm.

[0015] In some embodiments, the crucible is heated by a heater, and the heating power of the heater ranges from 40 kW to 90 kW.

[0016] In some embodiments, the resistivity of the crystal rod is 20Ω.cm -1 ~150Ω.cm -1 The range of nitrogen doping of the crystal rod is 0~5×10 13 atoms / cm 3 .

[0017] Correspondingly, the embodiment of the present application further provides a single crystal silicon, which is prepared by the above-mentioned single crystal silicon preparation method, and the oxygen content of the single crystal silicon is 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 .

[0018] In some embodiments, the oxygen content of the single crystal silicon is 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 . Beneficial effects

[0019] The present application provides a method for preparing single crystal silicon and single crystal silicon. The method for preparing single crystal silicon of the present application includes: pulling a crystal rod, wherein the crystal rod grows upward from a silicon melt; applying a magnetic field to the silicon melt, wherein the magnetic field has a zero magnetic field plane along the growth direction of the crystal rod, and a first distance H1 is provided between the zero magnetic field plane and the liquid surface of the silicon melt, satisfying the following: 0≤H1≤60mm. The present application controls the oxygen content of the prepared single crystal silicon to 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 The single crystal silicon is used in the manufacture of IGBT devices and can improve the performance of IGBT devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0021] FIG1 is a schematic diagram of the structure of the equipment used to prepare single crystal silicon in an embodiment of the present application;

[0022] Description of the drawings: 1-crystal rod, 2-silicon melt, 3-liquid surface of silicon melt, 4-heat shield, 5-water cooling screen, 6-crucible, 7-heater, 8-magnetic field device, 9-zero magnetic field plane.

[0023] Implementation Methods of the Application

[0024] The following will provide a clear and complete description of the technical solutions in the embodiments of the present application, in conjunction with the embodiments of the present application. It should be noted that the embodiments described are only a portion of the embodiments of the present application, and are not intended to be exhaustive. All other embodiments derived by persons skilled in the art based on the embodiments of the present application without inventive effort are intended to fall within the scope of protection of the present application. Furthermore, in the description of the present application, the term "including" means "including but not limited to." The terms "first," "second," and "third," etc., are used merely as designations and do not impose numerical requirements or establish an order. Various embodiments of the present application may be presented in the form of a range. It should be understood that describing in a range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the present application. Therefore, the range description should be considered to specifically disclose all possible subranges and individual numerical values ​​within the range. For example, a range description of 1 to 6 should be considered to specifically disclose subranges, such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., as well as individual numerical values ​​within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range.

[0025] The performance of single crystal silicon used to manufacture silicon wafers for IGBT devices (Insulate-Gate Bipolar Transistor) affects the quality of IGBT devices. To improve the quality of single crystal silicon, the present application provides a method for preparing single crystal silicon. As shown in FIG1 , the direction in which the X-axis extends is the bottom-up direction described in the present application, which is also the growth direction of the crystal rod 1 of the present application. The crucible 6 of the present application contains molten silicon 2, and the crystal rod 1 grows upward from the liquid surface 3 of the silicon molten liquid. The crystal rod 1 is surrounded by a heat shield 4.

[0026] In the present application, a second distance H2 mm is defined between the heat shield 4 and the silicon melt surface 3. In the present application, the distance between the heat shield 4 and the silicon melt surface 3 refers to the distance between the lower edge of the heat shield 4 and the silicon melt surface 3. In the present application, the distance between the heat shield 4 and the silicon melt surface 3 can be controlled by controlling the position of the heat shield 4 or the crucible 6.

[0027] In addition, a water-cooling shield 5 is provided on the periphery of the crystal ingot 1. A third distance H3 mm is defined between the water-cooling shield 5 and the silicon melt liquid level 3. In this application, the distance between the water-cooling shield 5 and the silicon melt liquid level 3 refers to the distance between the lower edge of the water-cooling shield 5 and the silicon melt liquid level 3. In this application, the distance between the water-cooling shield 5 and the silicon melt liquid level 3 can be controlled by controlling the position of the water-cooling shield 5 or the crucible 6.

[0028] A magnetic field device 8 for generating a CUSP is located around crucible 6. This device consists of upper and lower coils with opposite currents flowing through them. This device provides an inhomogeneous magnetic field, with a zero magnetic field plane 9 of the inhomogeneous magnetic field being a first distance H1 mm from the surface 3 of the silicon melt. In Figure 1 , "○" indicates current flowing out of the page, and "×" indicates current flowing into the page. A heater 7 is located around crucible 6 to maintain a temperature suitable for single crystal silicon growth by heating crucible 6.

[0029] In some embodiments, the present invention provides a method for preparing single crystal silicon, comprising: pulling a crystal ingot 1, wherein the crystal ingot 1 grows upward from a silicon melt 2; applying a magnetic field (CUSP magnetic field) to the silicon melt 2, wherein the magnetic field has a zero magnetic field plane 9, and a first distance H1 mm is defined between the zero magnetic field plane 9 of the non-uniform magnetic field and the liquid surface 3 of the silicon melt, satisfying the following: 0 ≤ H1 ≤ 60 mm. For example, the value of H1 (mm) can be any value selected from 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60, or a range consisting of any two values. By controlling the position at which the CUSP magnetic field is applied to the silicon melt 2, the present invention changes the distribution and intensity of the transverse and longitudinal magnetic fields in the melt, thereby controlling melt convection, thereby changing the generation, transport, and volatilization of oxygen, and changing the temperature gradient at the solid-liquid interface, thereby significantly reducing the oxygen content in the single crystal silicon while controlling the COP.

[0030] In some embodiments, a heat shield 4 is provided on the periphery of the crystal ingot 1. The lower edge of the heat shield 4 is at a second distance H2 from the liquid surface 3 of the molten silicon liquid, satisfying the following: 15 mm ≤ H2 ≤ 35 mm. For example, the value of H2 (mm) can be any value among 15, 20, 30, 35, or a range consisting of any two values. By controlling the distance between the lower edge of the heat shield 4 and the liquid surface 3 of the molten silicon liquid, the present application can change the ability of the airflow to blow above the melt surface, thereby facilitating oxygen volatilization, reducing the oxygen content of the single crystal silicon, and improving the radial temperature gradient difference of the thermal field. This controls the residence time of the crystal ingot 1 at 900°C to 1100°C, thereby controlling the COP defects of the crystal ingot.

[0031] In some embodiments, a water-cooling shield 5 is provided on the periphery of the crystal ingot 1. A third distance H3 is provided between the lower edge of the water-cooling shield 5 and the liquid surface 3 of the molten silicon liquid, satisfying the following conditions: 300 mm ≤ H3 ≤ 600 mm. For example, the value of H3 (mm) can be any value of 300, 350, 400, 450, 500, 550, 600, or a range consisting of any two values. By controlling the distance between the lower edge of the water-cooling shield 5 and the liquid surface 3 of the molten silicon liquid, the present application can control the radial temperature gradient of the thermal field, control the residence time of the crystal ingot 1 at 900°C to 1100°C, and achieve control of the COP defects of the crystal ingot.

[0032] In some embodiments, the field strength of the non-uniform magnetic field is 700 GS to 1100 GS. For example, the field strength (GS) of the non-uniform magnetic field is any value among 700, 800, 900, 1000, 1100, or a range consisting of any two values. The present application controls the field strength (GS) of the non-uniform magnetic field to change the transverse and longitudinal magnetic field strengths in the melt, thereby controlling the melt convection, achieving the purpose of changing the generation, transmission, and volatilization of oxygen, and changing the temperature gradient at the solid-liquid interface, thereby significantly reducing the oxygen content in the crystal rod 1 while controlling the COP.

[0033] In some embodiments, the rotation speed of the crystal ingot 1 is 8 rpm to 15 rpm. For example, the rotation speed (rpm) of the crystal ingot 1 can be any value among 8, 9, 10, 11, 12, 13, 14, and 15, or a range consisting of any two values. By controlling the rotation speed of the crystal ingot 1, the present application can control the temperature distribution and heat convection of the melt, thereby controlling the oxygen content of the single crystal silicon.

[0034] In some embodiments, the crystal rod 1 has a crystal pulling rate, and the crystal pulling rate range is: 0.3mm / min to 0.5mm / min. For example, the value of the crystal pulling rate is any value among 0.3, 0.35, 0.4, 0.45, 0.5, or a range consisting of any two values. During the crystal rod preparation process, the type of point defects that cause device defects is determined by the ratio of the crystal pulling rate (V) and the temperature gradient (G) at the solid-liquid interface. When V / G is greater than a critical value ξ, the vacancy concentration at the interface is higher than the interstitial concentration, and the point defects are mainly vacancies, and only vacancy-type defects are generated. When V / G is less than a certain critical value ξ, it is mainly self-interstitial atoms, forming a vortex defect of the dislocation ring type. When V / G is about 1.34×10 -3 cm 2 / min·K, the so-called "perfect silicon" can be obtained. When V / G is greater than 1.34×10 -3 cm 2 / min·K, vacancy defects, namely COP, are mainly generated. In order to control COP defects, in some embodiments, the crystal pulling rate and parameters in the crystal rod preparation process are controlled, and then the solid-liquid interface temperature gradient G is controlled. The COP defects can be reduced by controlling the value of V / G.

[0035] In some embodiments, the crystal rod 1 is placed in a purge atmosphere, and the pressure range of the purge atmosphere is 1600Pa to 2500Pa. For example, the pressure (Pa) of the purge atmosphere is any value among 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, or a range consisting of any two values. The present application affects the free interface gas flow rate and indirectly affects oxygen volatilization by controlling the pressure provided by the purge atmosphere; since the saturated vapor pressure of SiO is low, low furnace pressure is conducive to the escape of SiO, thereby affecting the oxygen content of the crystal rod 1 and ensuring that the oxygen content of the crystal rod 1 is maintained in a low range.

[0036] In some embodiments, the purge atmosphere includes argon.

[0037] In some embodiments, a heater 7 is provided on the periphery of the crucible 6, and the heating power of the heater 7 is 40 kW to 90 kW. For example, the heating power (kW) can be any value selected from 40, 50, 60, 70, 80, and 90, or a range consisting of any two values. By controlling the heating power, the present application can control the baking temperature of the quartz crucible by the heater and the oxygen content of the single crystal. If the power is lower than 40 kW, the heat source for the crystal pulling system is insufficient, the melting time of the silicon raw material is too long, and actual crystal pulling cannot be performed.

[0038] In some embodiments, the oxygen content of the crystal rod 1 is 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 For example, the oxygen content of the crystal rod 1 (atoms / cm 3 ) is 0.5×10 17 , 1×10 17 , 1.5×10 17 , 2×10 17 , 2.5×10 17 , 3.0×10 17 Any value or a range consisting of any two values ​​in the range. If the oxygen content of the crystal rod 1 of the present application is controlled within this range, the product performance of the prepared IGBT can be greatly improved. For example, the oxygen content in the crystal rod 1 is in the range of 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 .

[0039] In some embodiments, the molten silicon 2 is located in a crucible 6, and the crucible 6 rotates at a speed of 0.5 rpm to 4 rpm. For example, the crucible 6 rotation speed (rpm) can be any value selected from 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4, or a range consisting of any two values. By controlling the rotation speed of the crucible 6, the present application can control the temperature distribution and heat convection of the melt, thereby controlling the oxygen content in the crystal ingot 1.

[0040] In some embodiments, the resistivity of the crystal rod 1 is 20Ω.cm -1 ~150Ω.cm -1 . For example, the resistivity of crystal rod 1 (Ω.cm -1 ) is any value among 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, or a range consisting of any two values. When the resistivity of the crystal ingot 1 is within this range, the yield of the IGBT product can be improved. In some embodiments, the range of nitrogen doping of the crystal ingot 1 is 0 to 5×10 13 atoms / cm 3 . Such as crystal rod 1 nitrogen doping (atoms / cm 3 ) is 0, 1×10 13 , 2×10 13 , 3×10 13 , 4×10 13 , 5×10 13 The present application can also achieve the effect of reducing the COP size by controlling the range of nitrogen doping.

[0041] In the present application, the vacancy defect density of the crystal rod 1 is controlled to be 0-10 ea / piece, LLS (localized light-scatter, size ≥ 65 nm). The crystal rod 1 manufactured by the method of the present application achieves a low oxygen content level in the crystal rod 1 while reducing COP defects.

[0042] In some embodiments, the pulled crystal rod 1 is evenly sliced, and wafers are cut out for defect testing. In some embodiments, the diameter of the prepared crystal rod is 300 mm, and the thickness of the cut wafers is 0.775 mm. The cut wafers are tested for defectivity. 50 wafers cut from the head, 50 wafers cut from the middle, and 50 wafers cut from the tail of the crystal rod 1 are tested for defectivity. The average result of the test is: the vacancy defect density of the wafer is controlled at 0 to 10 ea / wafer. The applicant further randomly sampled 100 wafers cut from the crystal rod 1. The test results of the sampling also showed that the vacancy defect density of the wafers cut from the crystal rod 1 prepared in this application was controlled at 0 to 10 ea / wafer.

[0043] In some embodiments, the LLS test results are obtained by performing COP test on the prepared wafer using an SPX particle analyzer.

[0044] The embodiment of the present application further provides a single crystal silicon having an oxygen content of 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 In some specific embodiments, the oxygen content of the single crystal silicon is 0.5×10 17 atoms / cm 3 ~2.5×10 17 atoms / cm 3 .

[0045] In some embodiments, the following method is used to test the oxygen content in the head: using FT-IR (infrared spectroscopy), which is an analytical method for determining the molecular structure of a substance and identifying compounds based on information such as the relative vibration between atoms within the molecule and the molecular rotation.

[0046] In some embodiments, the resistivity of single crystal silicon is 20Ω.cm -1 ~150Ω.cm -1 The nitrogen doping range of single crystal silicon is 0~5×10 13 atoms / cm 3 Silicon wafers made from the single crystal silicon of the present application can significantly improve the product performance of IGBTs.

[0047] Example 1: Preparation of silicon raw material: Select polysilicon powder with a purity greater than 99.9% as the silicon raw material.

[0048] Feeding, heating, and melting: Silicon rods made from silicon powder are placed in a crucible 6, and the entire apparatus is then placed in a heating furnace. The furnace heats the silicon rods to 1600°C to 1620°C, melting them into a silicon melt 2.

[0049] Crystal growth: A rotating single-crystal silicon seed crystal is suspended on the surface of the silicon melt 2. The seed crystal is used as the starting point of the crystal rod 1. Crystal growth is carried out by rotation and lifting. The rotation speed of the crystal rod 1 is controlled to be 10 rpm, the pulling rate of the crystal rod 1 is 0.4 mm / min, the rotation speed of the crucible is 2 rpm, and the furnace pressure is maintained at 2000 Pa.

[0050] Cooling and solidification: When the crystal rod 1 grows to the desired size, the lifting and rotation are stopped to allow the silicon melt to cool and solidify to obtain single crystal silicon.

[0051] Example 2 to Example 9: The preparation method is the same as Example 1, except that the preparation parameters of the single crystal silicon are adjusted, see Table 1 for details.

[0052] Comparative Examples 1-2: The preparation method is the same as that of Example 1, except that the distance between the zero magnetic field interface of the CUSP and the surface of the silicon melt is adjusted.

[0053] Test method: The oxygen content in the head is tested using FT-IR infrared spectroscopy.

[0054] Table 1 Preparation parameters and test results of Examples 1 to 9 and Comparative Examples 1 to 2

[0055] From the results in Table 1, it can be seen that when the CUSP magnetic field zero plane is located 20 mm and 40 mm below the silicon melt surface, the oxygen concentration at the head is higher than 2.5×10 17 atoms / cm 3 On the contrary, when the CUSP magnetic field zero surface position is located at 60mm, 40mm, 20mm, and 0mm above the melt surface, the head oxygen concentration is controlled at 2.5×10 17 atoms / cm 3 Below, the overall single crystal silicon oxygen content is within the range of 0.5×10 17～ 2.5×10 17 atoms / cm 3 .

[0056] At the same time, COP defects were detected on single-crystal silicon wafers after slicing. The results showed that when the CUSP magnetic field zero plane was located at 20mm and 40mm below the liquid surface, the LLS (size ≥ 65nm) results were greater than 10ea / wafer. However, when the CUSP magnetic field zero plane was located at 60mm, 40mm, 20mm, and 0mm above the liquid surface, the LLS (size ≥ 65nm) results were all less than 10ea / wafer.

[0057] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0058] The above is a detailed introduction to the preparation method of single crystal silicon and single crystal silicon provided in the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for preparing single crystal silicon, wherein: The method comprises: Pulling a crystal rod (1), wherein the crystal rod (1) grows upward from a silicon melt (2); A magnetic field is applied to the silicon melt (2), and along the growth direction (X) of the crystal rod (1), the magnetic field has a zero magnetic field plane (9), and a first distance H1 is present between the zero magnetic field plane (9) and the liquid surface (3) of the silicon melt, satisfying: 0≤H1≤60mm.

2. The method for preparing single crystal silicon according to claim 1, wherein: A heat shield (4) is provided on the periphery of the crystal rod (1); along the growth direction (X) of the crystal rod, there is a second distance H2 between the heat shield (4) and the liquid surface (3) of the silicon melt, satisfying: 15 mm ≤ H2 ≤ 35 mm.

3. The method for preparing single crystal silicon according to claim 1, wherein: A water cooling screen (5) is arranged on the periphery of the crystal rod (1); along the growth direction (X) of the crystal rod (1), the water cooling screen (5) and the liquid surface (3) of the silicon melt have a third distance H3, which satisfies: 300mm≤H3≤600mm.

4. The method for preparing single crystal silicon according to claim 1, wherein: The field strength of the magnetic field ranges from 700 GS to 1100 GS.

5. The method for preparing single crystal silicon according to claim 1, wherein: In the step of pulling the crystal rod (1), the rotation speed of the crystal rod (1) ranges from 8 rpm to 15 rpm.

6. The method for preparing single crystal silicon according to claim 1, wherein: In the step of pulling the crystal rod (1), the pulling rate of the crystal rod (1) is in the range of 0.3 mm / min to 0.5 mm / min.

7. The method for preparing single crystal silicon according to claim 1, wherein: In the step of pulling the crystal rod (1), the crystal rod (1) is placed in a purge atmosphere, and the pressure range of the purge atmosphere is 1600Pa to 2500Pa.

8. The method for preparing single crystal silicon according to claim 7, wherein: The purge atmosphere includes argon gas.

9. The method for preparing single crystal silicon according to claim 1, wherein: The oxygen content of the crystal rod (1) is in the range of 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 .

10. The method for preparing single crystal silicon according to claim 1, wherein: The silicon melt (2) is located in a crucible (6), and the rotation speed of the crucible (6) is in the range of 0.5 rpm to 4 rpm.

11. The method for preparing single crystal silicon according to claim 10, wherein: The crucible (6) is heated by a heater (7), and the heating power of the heater ranges from 40 kW to 90 kW.

12. The method for preparing single crystal silicon according to claim 1, wherein: The resistivity of the crystal rod (1) is 20Ω.cm -1 ~150Ω.cm -1 The range of nitrogen doping in the crystal rod (1) is 0 to 5×10 13 atoms / cm 3 .

13. A silicon monocrystalline, wherein: The single crystal silicon is prepared by the method for preparing single crystal silicon according to any one of claims 1 to 12, and the oxygen content of the single crystal silicon is 0.5×10 17 atoms / cm 3 ~3.0×10 17 atoms / cm 3 .

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