电子束熔炼制备太阳能级多晶硅的研究现状与发展趋势

doi:10.15541/jim20140664

摘要/Abstract

摘要：

电子束熔炼具有高能量密度、高真空度等优点, 能够有效地去除硅中的挥发性杂质, 使其在制备太阳能级多晶硅材料方面具有巨大的优势和广阔的应用前景, 目前已经实现了产业化应用, 成为冶金法制备太阳能级硅材料的关键环节之一。本文在阐述挥发性杂质去除的热力学原理的基础上, 对其去除效果和去除机制进行了总结。同时, 针对电子束熔炼技术目前存在的问题, 结合作者在这些方面的探索, 从数值模拟、节能型熔炼方式以及与定向凝固技术的耦合等角度对现阶段的研究重点进行了综述, 并对其未来的发展趋势进行了展望。

关键词: 电子束熔炼, 多晶硅, 挥发性杂质, 综述

Abstract:

Electron beam melting is an effective method to remove volatile impurities in silicon due to its characteristics of high energy density and high vacuum degree, which has huge advantages and wide application prospects in preparation of solar-grade silicon. Currently it has been successfully applied in industry and become one of the key procedures for preparation of solar-grade silicon by metallurgical route. Based on the thermodynamic principle of the volatile impurities removal, the removal efficiency and mechanism are summarized in this paper. According to current problems of this technology combined with our own experience, the emphasis of current research is reviewed from the points of numerical simulation, energy-saving melting technology and coupling with directional solidification technology. The future development direction of this technology is also proposed.

Key words: electron beam melting, solar-grade silicon, volatile impurities, review

中图分类号:

TF134
TF89

谭毅, 石爽, 姜大川. 电子束熔炼制备太阳能级多晶硅的研究现状与发展趋势[J]. 无机材料学报, 2015, 30(8): 785-792.

TAN Yi, SHI Shuang, JIANG Da-Chuan. Progress in Research and Development of Solar-grade Silicon Preparation by Electron Beam Melting[J]. Journal of Inorganic Materials, 2015, 30(8): 785-792.

图/表 9

图1 硅中主要杂质的蒸发系数与温度的关系[20]

Fig. 1 Volatility coefficients of impurities in silicon as a function of temperature[20]

图2 电子束熔炼多晶硅过程示意图[21]

Fig. 2 Schematic diagram of silicon refining by electron beam melting[21]

图3 电子束熔炼制备的硅锭的宏观形貌[20]

Fig. 3 Morphologies of electron beam melted silicon ingot[20](a) Surface; (b) Bottom; (c) Cross section

图4 杂质在电子束熔炼制备的硅锭中的分布[26]

Fig. 4 Distribution of impurities in electron beam melted silicon ingot[26]

图5 硅中杂质蒸发的速率常数与温度的关系[15, 28-29, 37]

Fig. 5 Rate constant of impurity evaporation from silicon as a function of temperature[15, 28-29, 37]

图6 挥发性杂质从硅熔体到气相的传输过程[29]

Fig. 6 Schematic diagram of the migration process of impurity atom during different steps[29]

图7 0.5 kg的硅在电子束熔炼时的参数优化结果[42]

Fig. 7 The optimum value of melting parameters for 0.5 kg silicon by electron beam melting[42]

图8 小功率、浅熔池熔炼方式示意图[44]

Fig. 8 Process of electron beam melting with low power and shadow melten pool[44]

图9 电子束诱导多晶硅定向凝固铸锭[46]

Fig. 9 Directional solidified silicon ingot induced by electron beam[46]

参考文献 53

[1]	SWANSON R M.Photovoltaics power up.Science, 2009, 324(5929): 891-892.
[2]	POWELL D M, WINKLER M T, CHOI H J, et al.Crystalline silicon photovoltaics: a cost analysis framework for determining technology pathways to reach baseload electricity costs.Energy Environ. Sci., 2012, 5(3): 5874-5883.
[3]	COLETTI G.Sensitivity of state-of-the-art and high efficiency crystalline silicon solar cells to metal impurities.Prog. Photovoltaics, 2013, 21(5): 1163-1170.
[4]	TYAGI V V, RAHIM N A A, RAHIM N A, et al. Progress in solar PV technology: research and achievement.Renew. Sust. Energ. Rev., 2013, 20: 443-461.
[5]	BUONASSISI T, ISTRATOV A A, MARCUS M A, et al.Engineering metal-impurity nanodefects for low-cost solar cells.Nat. Mater., 2005, 4(9): 676-679.
[6]	HUDELSON S, NEWMAN B K, BERNARDIS S, et al.Retrograde melting and internal liquid gettering in silicon.Adv. Mater., 2010, 22(35): 3948-3953.
[7]	PIZZINI S.Towards solar grade silicon: challenges and benefits for low cost photovoltaics.Sol. Energy Mater. Sol. Cells, 2010, 94(9): 1528-1533.
[8]	CIFTJA A.Rrefining of solar cell silicon through metallurgical routes.JOM, 2012, 64(8): 933-934.
[9]	CORTES A D S, SILVA D S, VIANA G A, et al. Solar cells from upgraded metallurgical-grade silicon purified by metallurgical routes.J. Renew. Sustain. Energy, 2013, 5(2): 123-129.
[10]	YU W Z, MA W H, LV G Q, et al.Low-cost process for silicon purification with bubble adsorption in Al-Si melt.Metall. Mater. Trans. B, 2014, 45(4): 1573-1578.
[11]	FANG M, LU C H, HUANG L Q, et al.Multiple slag operation on boron removal from metallurgical-grade silicon using Na2O-SiO2 slags.Ind. Eng. Chem. Res., 2014, 53(30): 12054-12062.
[12]	CHOUDHURY A, HENGSBERGER E.Electron beam melting and refining of metals and alloys.ISIJ Int., 1992, 32(5): 673-681.
[13]	BAKISH R.The substance of a technology: Electron-beam melting and refining.JOM, 1998, 50(11): 28-30.
[14]	CASENAVE D, GAUTHIER R, PINARD P.A study of the purification process during the elaboration by electron bombardment of polysilicon ribbons designed for photovoltaic conversion.Sol. Energy Mater., 1981, 5(4): 417-423.
[15]	IKEDA T, MAEDA M.Purification of metallurgical silicon for solar-grade silicon by electron beam button melting.ISIJ Int., 1992, 32(5): 635-642.
[16]	KATO Y, HANAZAWA K, BABA H, et al.Purification of metallurgical grade silicon to solar grade for use in solar cell wafers.Tetsu To Hagane-J. Iron Steel Inst. Jpn., 2000, 86(11): 9-16.
[17]	YUGE N, ABE M, HANAZAWA K, et al.Purification of metallurgical-grade silicon up to solar grade. Prog. Photovoltaics, 2001, 9(3): 203-209.
[18]	MITRASINOVIC A M, D'SOUZA R, UTIGARD T A. Impurity removal and overall rate constant during low pressure treatment of liquid silicon.J. Mater. Process. Technol., 2012, 212(1): 78-82.
[19]	SAFARIAN J, TANGSTAD M.Vacuum refining of molten silicon.Metall. Mater. Trans. B, 2012, 43(6): 1427-1445.
[20]	王强. 电子束熔炼提纯冶金级硅工艺研究. 大连: 大连理工大学硕士学位论文, 2010.
[21]	WANG Q, DONG W, TAN Y, et al.Impurities evaporation from metallurgical-grade silicon in electron beam melting process.Rare Metals, 2011, 30(3): 274-277.
[22]	SUN J L, ZHANG J, WANG H W, et al.Purification of metallurgical grade silicon in an electron beam melting furnace.Surf. Coat. Technol., 2013, 228: S67-S71.
[23]	LIU T, DONG Z Y, ZHAO Y W, et al.Large scale purification of metallurgical silicon for solar cell by using electron beam melting.J. Cryst. Growth, 2012, 351(1): 19-22.
[24]	MIYAKE M, HIRAMATSU T, MAEDA M.Removal of phosphorus and antimony in silicon by electron beam melting at low vacuum.J. Jpn. Inst. Met., 2006, 70(1): 43-46.
[25]	OSOKIN V A, SHPAK P A, ISHCHENKO V V, et al.Electron- beam technology for refining polycrystalline silicon to be used in solar power applications.Metallurgist, 2008, 52(1/2): 121-127.
[26]	PIRES J C S, BRAGA A F B, MEI P R. Profile of impurities in polycrystalline silicon samples purified in an electron beam melting furnace.Sol. Energy Mater. Sol. Cells, 2003, 79(3): 347-355.
[27]	PIRES J C S, OTUBO J, BRAGA A F B, et al. The purification of metallurgical grade silicon by electron beam melting.J. Mater. Process. Technol., 2005, 169(1): 16-20.
[28]	PENG X, DONG W, TAN Y, et al.Removal of aluminum from metallurgical grade silicon using electron beam melting.Vacuum, 2011, 86(4): 471-475.
[29]	SHI S, DONG W, PENG X, et al.Evaporation and removal mechanism of phosphorus from the surface of silicon melt during electron beam melting.Appl. Surf. Sci., 2013, 266: 344-349.
[30]	TAN Y, GUO X L, SHI S, et al.Study on the removal process of phosphorus from silicon by electron beam melting.Vacuum, 2013, 93: 65-70.
[31]	彭旭. 电子束熔炼冶金硅中杂质蒸发行为研究. 大连: 大连理工大学硕士学位论文, 2011.
[32]	姜大川. 电子束熔炼提纯多晶硅的研究. 大连: 大连理工大学博士学位论文, 2012.
[33]	ASGHAR H M N U K, TAN Y, SHI S, et al. Removal of oxygen from silicon by electron beam melting.Appl. Phys. A, 2014, 115(3): 753-757.
[34]	SASAKI H, KOBASHI Y, NAGAI T, et al. Application of electron beam melting to the removal of phosphorus from silicon: toward production of solar-grade silicon by metallurgical processes. Adv. Mater. Sci. Eng., 2013, 2013: 857196-1-8.
[35]	SAFARIAN J, TANGSTAD M.Kinetics and mechanism of phosphorus removal from silicon in vacuum induction refining.High Temp. Mater. Process., 2012, 31(1): 73-81.
[36]	HANAZAWA K, YUGE N, KATO Y.Evaporation of phosphorus in molten silicon by an electron beam irradiation method.Mater. Trans., 2004, 45(3): 844-849.
[37]	KEMMOTSU T, NAGAI T, MAEDA M.Removal rate of phosphorus from molten silicon.High Temp. Mater. Process., 2011, 30(1/2): 17-22.
[38]	MAIJER D M, IKEDA T, COCKCROFT S L, et al.Mathematical modeling of residual stress formation in electron beam remelting and refining of scrap silicon for the production of solar-grade silicon.Mater. Sci. Eng. A, 2005, 390(1/2): 188-201.
[39]	KRAZE A, MUIZNIEKS A, BERGFELDS K, et al.Reduction of silicon crust on the crucible walls in silicon melt purifying processes with electron beam technology by low-frequency travelling magnetic fields.Magnetohydrodynamics, 2011, 47(4): 369-383.
[40]	CHOI S H, JANG B Y, LEE J S, et al.Effects of electron beam patterns on melting and refining of silicon for photovoltaic applications.Renew. Energy, 2013, 54: 40-45.
[41]	WEN S T, TAN Y, SHI S, et al.Thermal contact resistance between the surfaces of silicon and copper crucible during electron beam melting.Int. J. Therm. Sci., 2013, 74: 37-43.
[42]	TAN Y, WEN S T, SHI S, et al.Numerical simulation for parameter optimization of silicon purification by electron beam melting. Vacuum, 2013, 95: 18-24.
[43]	JIANG D C, TAN Y, SHI S, et al.Removal of phosphorus in molten silicon by electron beam candle melting.Mater. Lett., 2012, 78: 4-7.
[44]	JIANG D C, TAN Y, SHI S, et al.Evaporated metal aluminium and calcium removal from directionally solidified silicon for solar cell by electron beam candle melting.Vacuum, 2012, 86(10): 1417-1422.
[45]	JIANG D C, TAN Y, SHI S, et al.Research on new method of electron beam candle melting used for removal of P from molten Si.Mater. Res. Innov., 2011, 15(6): 406-409.
[46]	TAN Y, SHI S, GUO X L, et al.Effect of cooling rate on solidification of electron beam melted silicon ingots.Vacuum, 2013, 89: 12-16.
[47]	TAN Y, REN S Q, SHI S, et al.Removal of aluminum and calcium in multicrystalline silicon by vacuum induction melting and directional solidification.Vacuum, 2014, 99: 272-276.
[48]	JIANG D C, REN S Q, SHI S, et al.Phosphorus removal from silicon by vacuum refining and directional solidification.J. Electron. Mater., 2014, 43(2): 314-319.
[49]	JIANG D C, SHI S, TAN Y, et al.Research on distribution of aluminum in electron beam melted silicon ingot.Vacuum, 2013, 96: 27-31.
[50]	YUGE N, HANAZAWA K, KATO Y.Removal of metal impurities in molten silicon by directional solidification with electron beam heating.Mater. Trans., 2004, 45(3): 850-857.
[51]	LEE J K, LEE J S, JANG B Y, et al. Directional solidification behaviors of polycrystalline silicon by electron-beam melting. Jpn. J. Appl. Phys., 2013, 52(10): 10MB09-1-5.
[52]	LEE J K, LEE J S, JANG B Y, et al. Impurity segregation behavior in polycrystalline silicon ingot grown with variation of electron-beam power. Jpn. J. Appl. Phys., 2014, 53(8): 08NJ05-1-6.
[53]	MEI P R, MOREIRA S P, CARDOSO E, et al.Purification of metallurgical silicon by horizontal zone melting.Sol. Energy Mater. Sol. Cells, 2012, 98: 233-239.