JP3552278B2 - Method for producing silicon single crystal - Google Patents

Description

【００５０】
表１から明らかなように、本発明が規定する条件でシリコン単結晶を製造すれば、リングＯＳＦの発生位置をウェーハの最外周部にすることができ、しかも、ウェーハ面内の酸素析出物の密度を １０^５ｃｍ^−３程度に留めることができる。
【００５１】
【発明の効果】
本発明のシリコン単結晶の製造方法によれば、ウェーハ加工後の熱酸化処理によって発生するリングＯＳＦでＬＳＩ製造プロセスに支障が生ずることがなく、また酸化膜耐圧特性を低下させるウェーハ面内の酸素析出物の密度を抑制することができる。したがって、結晶品質に優れた単結晶を高能率に製造することができる。
【図面の簡単な説明】
【図１】引上げられた単結晶を溶融液および界面との関係で概略的に示した図である。
【図２】ウェーハに発生するリングＯＳＦの外径（ｍｍ）と結晶成長速度（ｆｐ：ｍｍ／ｍｉｎ ）との関係を示す図である。
【図３】リングＯＳＦの外径（ｍｍ）と単結晶の成長速度（ｆｐ：ｍｍ／ｍｉｎ ）およびシリコンの融点から１３００℃までの高温度範囲における結晶軸方向の温度勾配（Ｇ： ℃／ｍ）で表される係数（ｆｐ／ Ｇ： ｍｍ^２／℃・ｍｉｎ ）との関係を示す図である。
【図４】赤外散乱トモグラフ法での測定結果および冷却速度を示した図であり、（ａ）は酸素析出物の密度を、（ｂ）は酸素析出物の散乱強度の平方根を示し、（ｃ）は、１１５０℃〜１０００℃の温度範囲での冷却速度を示す。
【図５】チョクラルスキー法の実施状態を示す概略断面図である。
【符号の説明】
１…坩堝、 １ａ…石英製容器、 １ｂ…黒鉛製容器、 ２…加熱ヒーター、
３…種結晶、 ４…溶融液、 ５…単結晶[0001]
[Industrial applications]
The present invention relates to a method for manufacturing a silicon single crystal, and more particularly, to a method for manufacturing a silicon single crystal having excellent crystal quality such as an oxide film breakdown voltage characteristic by a Czochralski method.
[0002]
[Prior art]
Although there are various methods for producing a silicon single crystal used as an LSI material, a Czochralski method (hereinafter, referred to as a CZ method) is mainly employed as a method capable of industrial mass production.
[0003]
FIG. 5 is a schematic cross-sectional view showing an embodiment of the CZ method. In FIG. 5, reference numeral 1 denotes a crucible, which has a double structure including an inner quartz crucible 1a and an outer graphite crucible 1b. A heater 2 is provided outside the crucible 1, and a material for crystal formation melted by the heater, that is, a silicon melt 4 is accommodated in the crucible 1. By bringing the lower end of the seed crystal 3 attached to the tip of the pull rod or wire into contact with the surface of the melt 4 and pulling the seed crystal 3 upward while rotating the crucible and the seed crystal, the lower end of the melt 3 4 grows the solidified single crystal 5 at a constant growth rate. Usually, the growth rate employed is between 1.0 and 2.0 mm / min.
[0004]
During the pulling, oxygen impurities dissolved in the silicon melt from the quartz crucible are taken into the crystal. Therefore, supersaturated oxygen is dissolved in the silicon crystal lattice of the pulled single crystal. The interstitial oxygen atoms dissolved in the supersaturation cause defects (eg, oxygen precipitates, oxygen-induced stacking faults, dislocations, etc.) due to oxygen in the LSI manufacturing process, particularly in the thermal oxidation step, and these defects are generated in the device. In the active region, device characteristics are significantly reduced.
[0005]
In recent years, with the increase in the degree of integration of MOS devices, the thickness of a gate oxide film has been reduced, and there has been a strong demand for improvement in the reliability of the gate oxide film, that is, in the oxide film breakdown voltage characteristics. However, the reliability of the gate oxide film of a silicon single crystal wafer manufactured by the CZ method is remarkably inferior to that of a silicon single crystal wafer manufactured by a floating method (hereinafter, referred to as an FZ method) or an epitaxially grown wafer. For example, when an oxygen precipitate in a silicon single crystal, which is considered to be a cause of deteriorating the oxide film breakdown voltage characteristic, is measured by an infrared scattering tomography method, the density is 10 ⁶ cm ⁻³ in a silicon single crystal manufactured by the CZ method. The density is higher than that of oxygen precipitates in a single crystal grown by the FZ method or in an epitaxially grown wafer.
[0006]
There is a strong correlation between the density of oxygen precipitates observed immediately after the growth of the single crystal and the oxide breakdown voltage characteristics of the MOS device. By reducing the density of oxygen precipitates, the oxide breakdown voltage characteristics are improved. Can be done. However, oxygen precipitates grown during crystal growth are extremely stable thermally, and it is difficult to eliminate them at the thermal oxidation temperature (1250 ° C. or lower) commonly used in LSI manufacturing processes. When such oxygen precipitates are generated in the active region of the semiconductor device, not only the reliability of the gate oxide film is lowered but also the device characteristics are lowered due to the deterioration of the junction leak characteristics.
[0007]
When a silicon single crystal is pulled at a predetermined growth rate (0.8 mm / min) or higher, a ring-shaped oxygen-induced stacking fault (hereinafter referred to as a ring-shaped defect) is formed on the wafer surface by processing the silicon single crystal into a wafer and then performing a thermal oxidation treatment. , Ring OSF) may occur. Normally, since the ring OSF is generated at the outer peripheral portion of the wafer surface outside the active region, the ring OSF itself does not affect the manufacturing process. However, in the inner region of the ring OSF, oxygen precipitates having high thermal stability grown during crystal growth are distributed at a high density of about 10 ⁶ cm ⁻³ (however, the outer region of the ring OSF is not included). Has no oxygen precipitates). For this reason, there has been a problem that the reliability of the gate oxide film is lowered and the junction leak characteristic is lowered.
[0008]
Conventionally, as a method of suppressing the density of oxygen precipitates in a silicon single crystal pulled by the CZ method, it has been proposed to grow the single crystal at a low speed of 0.8 mm / min or less (for example, See JP-A-2-267195).
[0009]
By adopting such a low crystal growth rate, the present inventors can prevent the presence of oxygen precipitates in the single crystal or extremely reduce the density thereof, and significantly reduce the oxide film breakdown voltage characteristics. Confirmed that it can be improved.
[0010]
However, the growth rate of the single crystal means the pulling rate of the silicon single crystal, and is directly linked to the production rate of the silicon single crystal. Generally, in the industrial production of silicon single crystals, a pulling speed of 1.0 mm / min or more is adopted as described above. Will be greatly reduced.
[0011]
On the other hand, regarding the quality of the wafer, when the growth rate of the silicon single crystal is reduced (for example, 0.8 to 0.6 mm / min), the ring OSF is generated at the center of the wafer surface, and The density of oxygen precipitates in the wafer surface corresponding to the inner region may increase to about 10 ⁴ cm ⁻³ . When the growth rate is further reduced (for example, 0.6 mm / min or less), ring OSFs are not generated in the wafer surface, but dislocation clusters are newly generated at an area density of about 10 ³ cm ^−2. In addition, intrinsic gettering ability, which is an excellent property of a silicon single crystal manufactured by the CZ method, is significantly reduced.
[0012]
When a silicon single crystal of such quality is used for LSI manufacturing, the reliability of the gate oxide film is increased, but the overall reliability of the semiconductor device is reduced due to the generation of dislocation clusters and the remarkable decrease in intrinsic gettering ability. There was a problem that the property was reduced.
[0013]
[Problems to be solved by the invention]
The present invention overcomes the problems of the silicon single crystal manufacturing technique described above, reduces the density of oxygen precipitates in the wafer surface, and manufactures a silicon single crystal having excellent crystal quality such as oxide film breakdown voltage characteristics. The task was to establish a method.
[0014]
[Means for Solving the Problems]
The present inventors have studied the nucleation of oxygen precipitates and ring OSFs in a silicon single crystal observed immediately after crystal growth, and as a means of controlling the growth thereof, as a temperature gradient or cooling of a pulled silicon single crystal. Focused on speed.
[0015]
As a result, at the stage of producing a silicon single crystal, the crystal growth rate (ie, pulling rate: mm / min) and the temperature in the crystal axis direction in a high temperature range from the melting point of silicon (1410 ° C. to 1414 ° C.) to 1300 ° C. By keeping the relationship with the gradient (° C./mm) constant on the premise of a predetermined range of the temperature gradient G, the ring OSF generated by the thermal oxidation treatment after the wafer processing can prevent the ring OSF from being used in a range not used for LSI manufacturing. It has been found that oxygen precipitates in the crystal can be reduced in density (about 10 ⁵ cm ⁻³ ) by suppressing the cooling rate in the medium temperature region of the single crystal.
[0016]
The present invention has been completed based on such knowledge, and has a gist of the following method for producing a silicon single crystal.
[0017]
That is, in the method of manufacturing a silicon single crystal by the Czochralski method, the crystal growth rate is fp (mm / min), and the temperature gradient in the crystal axis direction in the temperature range from the melting point of silicon to 1300 ° C. is G (° C. / mm), the temperature gradient G in the crystal axis direction is set to 2.6 to 3.5 ° C./mm, the coefficient represented by fp / G is set to 0.25 mm ² / ° C. min or more, and 1150 ° C. A method for producing a silicon single crystal, characterized in that a crystal growth is performed at a cooling rate of 2.0 ° C./min or less and 1.1 ° C./min or more in a temperature range from to 1000 ° C.
[0018]
Here, the temperature gradient (° C./mm 2) is the rate at which the crystal is cooled, similarly to the cooling rate, and is indicated by the temperature (° C.) at which the crystal is cooled per unit length (1 mm) of the crystal.
[0019]
FIG. 1 is a diagram schematically showing a pulled single crystal 5 in relation to a melt 4 and an interface. Figure x ₀ on the crystal axes, that is, the interface on the X-X axis, the crystal so that initiate clotting from this position, x ₀ is the position of the melting point of silicon. x ₁ is the crystalline position on X-X axis, expressed by the distance from the interface (or the distance from the crystal bottom). Accordingly, if the _{x 1} and crystal is 1300 ° C. position, the temperature gradient G above, (1410 ℃ -1300 ℃) / ( the distance from _{x 0} to _{x 1:} mm) becomes.
[0020]
[Action]
The present inventors used a CZ method crystal manufacturing apparatus (four kinds) in which the apparatus size, the growth rate, the temperature gradient, and the like were different and the manufacturing conditions were different, and the relationship between the growth rate of the single crystal and the temperature gradient in the crystal. The occurrence of ring OSF due to thermal oxidation after wafer processing was investigated. The results of this survey are summarized below.
[0021]
{Circle around (1)} When using a crystal manufacturing apparatus under the same conditions, the outer diameter of the ring OSF generated on the wafer depends on the crystal growth speed, and the outer diameter of the ring OSF generated when the crystal is grown at a low speed becomes smaller. However, when the crystal manufacturing apparatus under different conditions is used, the outer diameter of the ring OSF generated on the wafer is different even at the same growth rate.
[0022]
{Circle around (2)} Even when using a crystal manufacturing apparatus under different conditions, if the temperature gradient in the crystal axis direction in a high temperature range from the melting point of silicon to about 1300 ° C. is controlled in addition to the growth rate of the single crystal, it is possible to obtain a wafer. The outer diameter of the generated ring OSF can be controlled. That is, the coefficient (fp / G: mm ² / ° C. · min) represented by the growth rate (fp: mm / min) of the single crystal and the temperature gradient (G: ° C./mm) in the axial direction of the single crystal is controlled. By doing so, the outer diameter of the generated ring OSF can be uniquely determined.
[0023]
FIG. 2 shows the relationship between the outer diameter (mm) of the ring OSF generated on the wafer and the crystal growth rate (fp: mm / min). Further, FIG. 3 shows the outer diameter (mm) of the ring OSF, the growth rate of the single crystal (fp: mm / min), and the temperature gradient in the crystal axis direction (G: ° C./m) in the high temperature range from the melting point of silicon to 1300 ° C. ) Indicates the relationship with the coefficient (fp / G: mm ² / ° C. · min).
[0024]
In FIGS. 2 and 3, the four types of manufacturing apparatuses 1 to 4 used are manufacturing apparatuses based on the CZ method, but the manufacturing conditions of the single crystal are different due to structural differences. However, in any of the manufacturing apparatuses, a quartz crucible having a diameter of 16 ″ is arranged, 35 kg of high-purity polycrystalline silicon is put as a raw material in the crucible, boron is doped, and the polycrystalline silicon is heated and melted. A silicon single crystal having a diameter of 150 mm and a crystal growth orientation of <100> was grown to a length of 700 mm (provided that the single crystal used had a crystal position within the range of 200 mm to 500 mm from the bottom). A total of 12 silicon single crystals were produced at growth rates of 0.4, 0.65, 0.75 and 0.95 mm / min (maximum pulling speed in each production apparatus).
[0025]
As is clear from FIG. 2, in any of the manufacturing apparatuses, as the crystal growth rate becomes lower, the position where the ring OSF is generated changes from the outer periphery to the center of the wafer, and the generated ring OSF is removed. Outer diameter becomes smaller. However, different manufacturing apparatuses have different outer diameters of the generated ring OSF even at the same crystal growth rate.
[0026]
As shown in FIG. 3, the coefficient (fp / G) represented by the crystal growth rate (fp: mm / min) and the temperature gradient (G: ° C./m) in the crystal axis direction during pulling of the silicon single crystal is set to 0. When the temperature is controlled to 0.22 mm ² / ° C. · min or less, almost no ring OSF is generated even if the thermal oxidation treatment is performed after the wafer processing. On the other hand, when the coefficient (fp / G) is in the range of 0.22 to 0.25 mm ² / ° C. · min, the ring OSF is generated at the center of the wafer surface (a portion having a radius of 15 to 60 mm from the center). . Further, when the coefficient (fp / G) exceeds 0.25 mm ² / ° C. · min, the ring OSF is generated on the outer peripheral portion of the wafer surface.
[0027]
By processing the relationship between the crystal growth rate (fp) and the temperature gradient (G) in the crystal axis direction by a coefficient (fp / G), the position where the ring OSF is generated is uniquely determined without depending on the manufacturing apparatus. be able to.
[0028]
In the method of the present invention, the pulling condition is set so that the coefficient (fp / G) becomes 0.25 mm ² / ° C. · min or more, so that the ring OSF generated by the thermal oxidation treatment is generated on the outer peripheral portion of the wafer surface. To grow a single crystal.
[0029]
Furthermore, the present inventors have made detailed studies on the nucleation of oxygen precipitates formed during crystal growth and the growth behavior thereof, and as a result, utilize the point defects, particularly vacancies, in the silicon single crystal. Thus, it was found that the density and the like of the oxygen precipitate observed in the crystal can be controlled.
[0030]
Generation of oxygen precipitates in the silicon single crystal proceeds by a reaction represented by the following formula (A).
[0031]
(1 + z) Si + 2Oi + 2yV = SiO 2 + zI ··· (A)
Here, Si: silicon atoms at lattice positions, Oi: oxygen atoms between lattices V: vacancies, I: silicon atoms between lattices, SiO ₂ : oxygen precipitates y: vacancies absorbed with the growth of oxygen precipitates Coefficient z representing the proportion of holes: coefficient representing the proportion of interstitial silicon atoms released with the growth of the oxygen precipitate On the other hand, the free energy of formation △ G of the oxygen precipitate is expressed by the following equation (B). You. However, for simplicity, the contribution of interstitial silicon and the contribution of strain due to the growth of precipitates are not considered here.
[0032]
^{△ G = -n (r) KTln} (Co / Co *) -yn (r) KTln (Cv / Cv *) + 4 πr 2 σ ··· (B)
Here, n (r): the number of oxygen atoms in the oxygen precipitate of radius r: K: Boltzmann constant, T: temperature, Co is the oxygen concentration Co ^* : thermal equilibrium concentration of oxygen, Cv: vacancy concentration Cv ^* : vacancy Thermal equilibrium concentration, σ: Interfacial energy of oxygen precipitates From the equation (B), if the vacancy concentration Cv is lower than the thermal equilibrium concentration Cv ^* , the second term {−yn (r) KTln (Cv / Cv ^* )} is Positive, increasing the energy barrier for nucleation, making nucleation difficult. Conversely, if the vacancy concentration Cv is present in excess of the thermal equilibrium concentration Cv ^* , the second term {-yn (r) KTln (Cv / Cv ^* )} becomes negative, and the energy barrier is reduced. Therefore, nucleation proceeds easily, and according to the experimental results of the present inventors, oxygen precipitation becomes possible even at a relatively high temperature of about 1150 ° C. Further, when the crystal temperature is lowered with the pulling of the single crystal, the thermal equilibrium concentrations of oxygen and vacancies Co ^* and Cv ^* are lowered, so that the energy barrier is further sharply lowered. Nucleation is easier.
[0033]
In the cooling process of the single crystal in the temperature range of 1150 ° C. to 1000 ° C., if the vacancy concentration Cv is present in excess of the thermal equilibrium concentration Cv ^* , nucleation is possible in this temperature range. Because of the high temperature of the crystals, the growth rate of oxygen precipitates is high. However, the vacancies are absorbed and consumed with the growth of the precipitates, so that the vacancy concentration Cv in the crystal starts to decrease, and as a result, the second term ｛-yn (r) KTln in the equation (B) Since (Cv / Cv ^* )｝ gradually increases, the energy barrier for nucleation increases with the progress of precipitation, and nucleation starts to be suppressed again.
[0034]
Therefore, when the vacancy concentration Cv in the crystal in the temperature range where oxygen precipitation starts (around 1150 ° C.) is constant and is present in excess of the thermal equilibrium concentration Cv ^* , the density of oxygen precipitates formed And the size thereof (hereinafter referred to as size) depend on the cooling rate of the single crystal in the temperature range of 1150 ° C. to 1000 ° C. (or the residence time of the crystal in the temperature range of 1150 ° C. to 1000 ° C.). In other words, if the cooling rate in this temperature range is reduced, the residence time of the crystal becomes longer, so that the growth of the oxygen precipitate is promoted and its size becomes larger. Further, since the vacancy concentration Cv decreases with the growth of the oxygen precipitate, the nucleation of the precipitate is suppressed, and the density of the oxygen precipitate subsequently generated decreases.
[0035]
Next, the fact that the density distribution and size of oxygen precipitates in a single crystal can be controlled by adjusting the cooling rate in the temperature range of 1150 ° C. to 1000 ° C. will be described based on experimental data.
[0036]
The method of manufacturing the silicon single crystal used in the experiment is almost the same as that of FIGS. 2 and 3, in which 50 kg of high-purity polycrystalline silicon is charged into a 16 ″ -diameter quartz crucible and doped with boron. Thereafter, the polycrystalline silicon was heated and melted, and was pulled up to a crystal length of 800 mm as a silicon single crystal having a diameter of 130 mm and a crystal growth direction of <100>.
[0037]
To adjust the cooling rate, when the length of the single crystal becomes 300 mm during pulling, the crystal growth rate (pulling rate) is changed from 1.1 mm / min to 0.5 mm / min, and When the length became 450 mm, the growth rate was changed from 0.5 mm / min to 1.1 mm / min to produce a crystal. As described above, by changing the crystal growth rate during the pulling of the crystal, it is possible to continuously change the cooling rate of the silicon single crystal at a position in the crystal growth axis direction.
[0038]
The silicon single crystal thus manufactured was processed into a wafer, mirror-polished, and the density and size of the oxygen precipitate present at the center of the wafer were measured by infrared scattering tomography.
[0039]
4A and 4B are graphs showing the measurement results by the infrared scattering tomography method and the cooling rate. FIG. 4A shows the density of the oxygen precipitate, and FIG. 4B shows the square root of the scattering intensity of the oxygen precipitate. Is shown. Here, the square root of the scattering intensity is considered to be a value proportional to the volume of the oxygen precipitate as the scatterer, and thus indicates the size of the oxygen precipitate. Further, FIG. 4 (c) shows the result of actually measuring the cooling rate in the temperature range of 1150 ° C. to 1000 ° C. at each crystal position.
[0040]
As is clear from FIG. 4 (a), when the crystal position is in the range of 180 mm to 255 mm, the cooling rate is 1.1 ° C./min, the density of oxygen precipitates is about 10 ⁵ cm ⁻³ , It is significantly reduced compared to the range. At other crystal positions, the density of oxygen precipitates gradually increases as the cooling rate increases, and when the cooling rate exceeds 2.0 ° C./min, the density increases to 10 ⁶ cm ⁻³ or more.
[0041]
On the other hand, from FIG. 4 (b), it is presumed that the square root of the scattering intensity is increased when the crystal position is in the range of 180 mm to 255 mm, and the size of the oxygen precipitate is increased.
[0042]
However, it is known that there is a strong correlation between the density of oxygen precipitates and the oxide film breakdown voltage characteristics of MOS devices. However, there is no clear knowledge on the relationship between the size of oxygen precipitates and crystal quality. Not yet obtained.
[0043]
In the method of the present invention, in order to reduce the density of oxygen precipitates in the wafer surface, it is essential that the cooling rate in a temperature range from 1150 ° C. to 1000 ° C. be 2.0 ° C./min or less. Hereinafter, the effects of the method of the present invention will be described in detail based on examples.
[0044]
【Example】
Using a silicon single crystal manufactured under the following conditions as a test material, the location of the ring OSF generated in the thermal oxidation treatment after wafer processing and the density of oxygen precipitates observed on the wafer surface by infrared scattering tomography were measured. did.
[0045]
1. Production Method of Single Crystal 50 kg of high-purity polycrystalline silicon is put into a quartz crucible having a diameter of 16 ″, boron is doped, and the polycrystalline silicon is melted by heating. Then, a single crystal having a diameter of 150 mm and a crystal growth orientation of <100> is obtained. Pull up length 1000mm.
[0046]
2. Conditional crystal growth rate (fp) in the crystal temperature range from the melting point of silicon to 1300 ° C. The crystal growth rate (fp) is 0.7 to 1.2 mm / min, and the temperature gradient (G) in the crystal axis direction is 2.6 to 3.5 ° C. / Mm ^{2, the} coefficient represented by fp / G is 0.25 mm ² / ° C. min or more.
[0047]
3.1 Conditional cooling rate in the crystal temperature range from 150 ° C to 1000 ° C: 2.5 to 2.2 ° C / min, 2.0 to 1.8 ° C / min, 1.5 to 1.1 ° C / min And four conditions of 1.0 to 0.7 ° C./min.
[0048]
Table 1 shows the measurement results under the above conditions.
[0049]
[Table 1]

[0050]
As is evident from Table 1, when a silicon single crystal is manufactured under the conditions specified by the present invention, the ring OSF can be generated at the outermost peripheral portion of the wafer, and the oxygen precipitate in the wafer surface can be removed. The density can be kept at about 10 ⁵ cm ⁻³ .
[0051]
【The invention's effect】
According to the method for manufacturing a silicon single crystal of the present invention, the ring OSF generated by the thermal oxidation process after the wafer processing does not hinder the LSI manufacturing process, and the oxygen in the wafer surface that lowers the oxide film breakdown voltage characteristic. The density of the precipitate can be suppressed. Therefore, a single crystal having excellent crystal quality can be manufactured with high efficiency.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a pulled single crystal in relation to a melt and an interface.
FIG. 2 is a diagram showing a relationship between an outer diameter (mm) of a ring OSF generated on a wafer and a crystal growth rate (fp: mm / min).
FIG. 3 shows an outer diameter (mm) of a ring OSF, a growth rate of a single crystal (fp: mm / min), and a temperature gradient in a crystal axis direction in a high temperature range from the melting point of silicon to 1300 ° C. (G: ° C./m). FIG. 4 is a diagram showing a relationship with a coefficient (fp / G: mm ² / ° C. · min) represented by).
FIGS. 4A and 4B are diagrams showing a measurement result by an infrared scattering tomography method and a cooling rate. FIG. 4A shows the density of oxygen precipitates, FIG. 4B shows the square root of the scattering intensity of oxygen precipitates, c) shows a cooling rate in a temperature range of 1150 ° C to 1000 ° C.
FIG. 5 is a schematic cross-sectional view showing an embodiment of the Czochralski method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Crucible, 1a ... Quartz container, 1b ... Graphite container, 2 ... Heater,
3 ... seed crystal, 4 ... melt, 5 ... single crystal

Claims (1)

In a method of manufacturing a silicon single crystal by the Czochralski method, a crystal growth rate is fp (mm / min), and a temperature gradient in a crystal axis direction in a temperature range from the melting point of silicon to 1300 ° C. is G (° C./mm). , The temperature gradient G in the crystal axis direction is set to 2.6 to 3.5 ° C./mm, the coefficient represented by fp / G is set to 0.25 mm ² / ° C. min or more, and from 1150 ° C. to 1000 A method for producing a silicon single crystal, wherein a crystal is grown at a cooling rate of 2.0 ° C./min or less and 1.1 ° C./min or more in a temperature range up to 100 ° C.

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