Cu对Al-50%Si合金法提纯太阳能级多晶硅过程中初晶硅Al含量影响研究

摘要/Abstract

摘要： Al-Si合金法提纯具有生产成本低、除杂效率高、副产物单一等特点,是一种极具潜力的太阳能级多晶硅原料的制备方法。在该工艺路线中,Al作为溶剂不可避免地会对Si产生污染,如何降低初晶硅中Al的含量是亟需解决的问题之一。本文通过向Al-50%Si合金中加入Cu,分析Cu对合金溶液热力学性能的影响,结合Cu的存在方式,探讨Cu对Al污染的抑制作用。结果表明:在Al-50%Si合金中添加10%(质量分数)Cu后,合金中Al的活度系数降低至0.714 8;初晶硅中Al的含量从250.960 mg/kg降低到181.637 mg/kg,比未添加Cu时减少了27.62%,同时,Cu在初晶硅中的残留仅为12.6 mg/kg,低于Cu在Si中的固溶度。可见,在Al-Si合金中引入Cu并未对初晶硅造成二次污染。因此,采用Al-Si-Cu三元合金体系进行提纯制备太阳能级多晶硅能够有效抑制Al对初晶硅的污染。

关键词: Al-Si合金, Cu, Al含量, 活度系数, Al₂Cu, 初晶硅

Abstract: Al-Si alloy purification method is an up-and-coming method for the preparation of solar-grade polysilicon raw materials because of its low production cost, high removal efficiency and single by-product. In this process, Al as a solvent will inevitably contaminate Si, and how to reduce the content of Al in primary silicon is one of the urgent problems to be solved. In this paper, a small amount of Cu was added to Al-50%Si alloy, the effect of Cu on the thermomechanical properties of the alloy solution was analyzed, and the inhibitory effect of Cu on Al contamination in combination with the existing form of Cu was explored. The results show that the activity coefficient of Al in the alloy reduces to 0.714 8 with 10% (mass fraction) Cu addition. The content of Al in the primary silicon reduces from 250.960 mg/kg to 181.637 mg/kg, which is 27.62% less than that without the addition of Cu. Meanwhile, the residual Cu in primary silicon is only 12.6 mg/kg, which is lower than the solid solution of Cu in Si. The introduction of Cu into the Al-Si alloy does not cause secondary contamination of the primary silicon. Therefore, using Al-Si-Cu ternary alloy system for purification to prepare solar-grade polysilicon can effectively suppress Al contamination of primary silicon.

Key words: Al-Si alloy, Cu, Al content, activity coefficient, Al₂Cu, primary silicon

中图分类号:

O782
TQ127.2

陈文雨, 刘家旭, 刘嘉霖, 陈嘉慧, 张银涛, 唐洪, 赵紫薇, 高忙忙. Cu对Al-50%Si合金法提纯太阳能级多晶硅过程中初晶硅Al含量影响研究[J]. 人工晶体学报, 2023, 52(9): 1660-1667.

CHEN Wenyu, LIU Jiaxu, LIU Jialin, CHEN Jiahui, ZHANG Yintao, TANG Hong, ZHAO Ziwei, GAO Mangmang. Effect of Cu on the Al Content of Primary Silicon During the Purification of Solar-Grade Polysilicon by Al-50%Si Alloy Method[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2023, 52(9): 1660-1667.

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