直拉法单晶硅生长的氧含量控制研究

doi:10.16553/j.cnki.issn1000-985x.2025.0028

摘要/Abstract

摘要： 直拉法生长的单晶硅是制备N型高效太阳能电池的原材料，晶体中的氧含量直接关系到太阳能电池的效率和稳定性。通过改变单晶硅生长过程中的坩埚壁面温度分布减少氧溶解是降低晶体中氧含量的重要方法。本文提出了三种改变坩埚壁面温度分布的加热器结构方案，并通过数值模拟研究了其对温度分布、熔体流动、结晶界面形状和氧杂质输运的影响规律。研究结果表明：采用长侧部加热器方案时，坩埚壁面温度呈现先增后减的分布趋势，其结晶界面挠度和氧含量较高；采用短侧部加热器方案和隔热环方案时，坩埚壁面温度呈现单调递增的分布趋势，其结晶界面挠度和氧含量较低，这与不同方案下的温度分布、熔体流动及氧杂质在坩埚壁面的溶解和在熔体中的输运特性密切相关；进一步总结提出了一套完整的氧输运分析方法，即通过绘制氧在熔体内部的输运路径，明确结晶界面处氧的准确来源及输运过程，为降低单晶硅内部的氧含量提供了理论依据和方法支撑。

关键词: 太阳能用单晶硅; 直拉法; 热质输运; 结晶界面; 氧杂质; 数值模拟

Abstract: Single crystal silicon by Czochralski method is the raw material for preparing N-type high-efficiency solar cells， and its oxygen content is directly related to the efficiency and stability of solar cells. Reducing the oxygen dissolution rate by changing the crucible wall temperature distribution during the growth of single crystal silicon is an important method for oxygen reduction. This paper proposes three structural solutions of the heater to change the temperature distribution of the crucible wall and studies their effects on temperature distribution， melt flow， crystallization interface shape and oxygen impurity transport by numerical simulation. The results show that when the long side heater is used， the crucible wall temperature increases first and then decreases， and its crystallization interface deflection and oxygen content are the highest， when the short side heater scheme and the insulation ring scheme are used， the crucible wall temperature presents a monotonically increasing distribution， and the crystallization interface deflection and oxygen content are lower， which are closely related to the temperature distribution， the melt flow， and the solubility of the oxygen impurities in the crucible wall and transport properties in the different schemes. A complete set of oxygen transport analysis methods is further summarised and proposed： the exact source and transport process of oxygen at the crystallization interface are clarified by mapping the transport path of oxygen in the melt. This method provides a theoretical basis for reducing the oxygen content inside single crystal silicon.

Key words: monocrystalline silicon for solar energy; Czochralski method; thermal and mass transport; crystallization interface; oxygen impurity; numerical simulation

中图分类号:

O782⁺.5

李建铖, 钟泽琪, 王军磊, 李早阳, 文勇, 王磊, 刘立军. 直拉法单晶硅生长的氧含量控制研究[J]. 人工晶体学报, 2025, 54(9): 1525-1533.

LI Jiancheng, ZHONG Zeqi, WANG Junlei, LI Zaoyang, WEN Yong, WANG Lei, LIU Lijun. Control of Oxygen Content During the Growth of Single Crystal Silicon by Czochralski Method[J]. Journal of Synthetic Crystals, 2025, 54(9): 1525-1533.

图/表 12

图1 不同设计方案的示意图

Fig.1 Schematic diagram of different design options

表1 材料物性参数

Table 1 Physical properties parameters of materials

Material	Density /（kg⋅m^-3）	Heat capacity /（J⋅kg^-1⋅K^-1）	Thermal conductivity /（W⋅m^-1⋅K^-1）	Emissivity	Viscosity /（Pa⋅s）	Latent heat /（J⋅kg^-1）
Silicon melt	2 530	1 000	64	0.3	8×10^-4	1 810 000
Argon	—	520.64	0.01+2.5×10^-5T	—	4.95×10^-6	—
Silicon crystal	2 330	1 059	22	0.7	—	—
Quartz	2 650	1 232	4	0.85	—	—
Graphite	2 300	2 019	90	0.8	—	—
Steel	7 900	477	15	0.6	—	—
Carbon felt	2 101	-317+4.03T-2.4×10^-4T²+5.0×10^-7T³	0.334-1.83×10^-4T+2.15×10^-7T²-1.89×10^-11T³	0.45	—	—
Carbon/Carbon composite materials	1 450	1 800	40	0.8	—	—

图2 网格无关性验证结果

Fig.2 Grid-independence verification results

图3 硅熔体内部温度分布（单位：K）

Fig.3 Temperature distribution in the silicon melt （Unit： K）

图4 坩埚壁面温度沿Y轴分布

Fig.4 Crucible wall temperature distribution along the Y-axis

图5 硅熔体内部流函数分布（单位：kg/s）

Fig.5 Stream function distribution in the silicon melt （Unit： kg/s）

图6 结晶界面挠度径向分布

Fig.6 Radial distribution of deflection at the crystalline interface

图7 熔体内部氧含量分布（单位：ppma）及氧输运路径（箭头线）

Fig.7 Oxygen content distribution （unit： ppma） and oxygen transport path in the melt （arrow line）

图8 氧溶解速率沿对称面内坩埚内壁面位置的分布

Fig.8 Distribution of oxygen dissolution rate along the position of the inner wall surface of the crucible in the symmetry plane

图9 坩埚底部中心到结晶界面中心处湍流黏度分布

Fig.9 Distribution of turbulent viscosity from the center of the crucible bottom to the center of the crystalline interface

图10 结晶界面处氧含量

Fig.10 Oxygen content at the crystalline interface

图11 实验和计算的氧含量结果

Fig.11 Experimental and calculation results of oxygen content

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