Directional Growth of Bulk Silicon from Si-Al-Sn Melts

doi:10.15541/jim20150649

Abstract

Abstract:

To separate primary Si from Si-Al-Sn alloy, directional solidification method was applied in this study. The effects and mechanisms of the cooling rate, alloy composition, and G/R ratio on bulk Si growth were investigated for optimizing parameters. By using of the constitutional supercooling criterion for single-phase growth from melts, the effects of Sn addition have been explored as compared with Si-Al and Si-Sn alloys. Finally, with the application of electron probe micro analyzer, the microstructure of Si and the distribution of Al and Sn were analyzed. Based on the obtained results, the directional solidification method is verified to be an effective method to separate Si from Si-Al-Sn alloy without any metal inclusions. The contents of Al and Sn in bulk Si are almost equivalent to the corresponding solid solubility. The obtained results indicate that directional solidification method can be an appropriate and effective technique to separate Si from alloy.

Key words: Si-Al-Sn alloy, directional solidification method, bulk Si

CLC Number:

TF114
TF89

Li Ya-Qiong, Li Jia-Yan, Tan Yi, Zhang Li-Feng, Morita Kazuki. Directional Growth of Bulk Silicon from Si-Al-Sn Melts[J]. Journal of Inorganic Materials, 2016, 31(8): 791-796.

Figures/Tables 10

References 18

[1]	YOSHIKAWA T, MORITA K.Thermodynamics on the Solidification Refining of Silicon with Si-Al Melts. EPD Congress-TMS 2005 Annual Meeting and Exhibition. San Francisco, 2005: 549-558.
[2]	YOSHIKAWA T, MORITA K. Refining of Si by the solidification of Si-Al melt with electromagnetic force. ISIJ International, 2005, 45(7): 967--971.
[3]	MURRAY J, MCALISTER A.The Al-Si (aluminum-silicon) system.Journal of Phase Equilibria, 1984, 5: 74-84.
[4]	LI J Y, LIU Y, TAN Y, et al.Effect of tin addition on primary silicon recovery in Si-Al melt during solidification refining of silicon.Journal of Crystal Growth, 2013, 371: 1-6.
[5]	LI Y Q, TAN Y, LI J Y, et al.Effect of Sn content on microstructure and boron distribution in Si-Al alloy. Journal of Alloy and Compounds, 2014, 583(1): 85-90.
[6]	JACOBS M H G, SPENCER P J. A thermodynamic evaluation of the system Si-Sn.Calphad, 1996, 20: 89-91.
[7]	JIE W Q.Progress of solidification principles and the applications.Materials China, 2014, 6: 321-326.
[8]	KURZ W, FISHER K.Fundamentals of Solidification, Switzerland: Trans Tech Publications, 1986, 91.
[9]	NISHI Y, KANG Y, MORITA K.Control of Si crystal growth during solidification of Si-Al melt.Materials Transactions, 2010, 51(7): 1227-1230.
[10]	MA X D, YOSHIKAWA T, MORITA K.Si growth by directional solidification of Si-Sn alloys to produce solar-grade Si.Journal of Crystal Growth, 2013, 377(0): 192-196.
[11]	OHSHIMA Y, YOSHIKAWA T, MORITA K.Effect of solidification conditions on Si growth from Si-Cu melts.Supplemental Proceedings: Materials Processing and Energy Materials, 2011, 1: 677-684.
[12]	LI Y Q, TAN Y, MORITA K.Directional Growth of Bulk Silicon from Silicon-Aluminum-Tin Melts. EPD Congress 2015-TMS 2015 Annual Meeting and Exhibition. San Francisco, 2015: 197-208.
[13]	KVANDE R, MJ S Y, RYNINGEN B. Growth rate and impurity distribution in multicrystalline silicon for solar cells. Materials Scienc and Engineering:A, 2005, 413-414: 545-549.
[14]	KURODA E, SAITOH T.Growth and characterization of polycrystalline silicon ingots from metallurgical grade source material.Journal of Crystal Growth, 1979, 47(2): 251-260.
[15]	SAFARIAN J, KOLBEINSEN L, TANGSTAD M.Thermodynamic activities in silicon binary melts.Journal of Materials Science, 2012, 47: 5561-5580.
[16]	SAFARIAN J, KOLBEINSEN L, TANGSTAD M.Liquidus of silicon binary systems.Metallurgical and Materials Transactions B, 2011, 42: 852-874.
[17]	YOSHIKAWA T, MORITA K.Solid Solubilities and thermodynamic properties of aluminum in solid silicon.Journal of The Electrochemical Society, 2003, 150(8): 465-468.
[18]	OLESINSHI R W, ABBASCHIAN G J.The Si-Sn (silicon-tin) system.Journal of Phase Equilibria, 1984, 5(3): 273-276.

No.	Composition/mol%			Lowering rate/ (mm•min^-1)	Cooling rate/ (K•min^-1)	G/ (K•mm^-1)	Growth rate ,R/(×10³, mm.min^-1)	(G/R)/ (K∙min•mm^-2)	Bulk Si length/mm	Interface morphology
No.	Si	Al	Sn	Lowering rate/ (mm•min^-1)	Cooling rate/ (K•min^-1)	G/ (K•mm^-1)	Growth rate ,R/(×10³, mm.min^-1)	(G/R)/ (K∙min•mm^-2)	Bulk Si length/mm	Interface morphology
J2-1	30.8	59.2	10	0.02	0.063	3.13	1.05	2980.95	1.81	?
J2-2	28.9	56.1	15	0.02	0.063	3.13	0.67	4671.64	1.16	?
J2-3	26.5	53.5	20	0.02	0.063	3.13	0.63	4968.25	1.09	?
J2-4	22.2	47.8	30	0.02	0.063	3.13	0.88	3556.82	1.52	×
J2-5	26.5	53.5	20	0.02	0.076	3.79	0.92	4119.57	1.21	?
J2-6	24.5	50.5	25	0.02	0.076	3.79	0.95	3989.47	1.24	×
J2-7	22.2	47.8	30	0.02	0.076	3.79	1.01	3752.48	1.33	×
J2-8	30.8	59.2	10	0.02	0.094	4.69	1.15	4078.26	1.28	?
J2-9	26.5	53.5	20	0.02	0.094	4.69	3.87	1211.89	4.33	×
J4-1	28.9	56.1	15	0.04	0.125	3.13	1.76	1778.41	1.52	×
J4-2	26.5	53.5	20	0.04	0.125	3.13	1.71	1830.41	1.47	×
J4-3	33.5	61.5	5	0.04	0.152	3.79	2.13	1779.34	1.4	?
J4-4	26.5	53.5	20	0.04	0.152	3.79	9.51	398.53	6.24	×
J8-1	28.9	56.1	15	0.08	0.250	3.13	1.74	1798.85	0.75	×
J8-2	26.5	53.5	20	0.08	0.250	3.13	13.85	225.99	5.97	×
J8-3	24.5	50.5	25	0.08	0.250	3.13	3.41	917.89	1.47	×
J8-4	22.2	47.8	30	0.08	0.250	3.13	1.55	2019.35	0.67	×

No.	Composition/mol%			Lowering rate/ (mm•min^-1)	Cooling rate/ (K•min^-1)	G/ (K•mm^-1)	Growth rate ,R/(×10³, mm.min^-1)	(G/R)/ (K∙min•mm^-2)	Bulk Si length/mm	Interface morphology
No.	Si	Al	Sn	Lowering rate/ (mm•min^-1)	Cooling rate/ (K•min^-1)	G/ (K•mm^-1)	Growth rate ,R/(×10³, mm.min^-1)	(G/R)/ (K∙min•mm^-2)	Bulk Si length/mm	Interface morphology
J2-1	30.8	59.2	10	0.02	0.063	3.13	1.05	2980.95	1.81	?
J2-2	28.9	56.1	15	0.02	0.063	3.13	0.67	4671.64	1.16	?
J2-3	26.5	53.5	20	0.02	0.063	3.13	0.63	4968.25	1.09	?
J2-4	22.2	47.8	30	0.02	0.063	3.13	0.88	3556.82	1.52	×
J2-5	26.5	53.5	20	0.02	0.076	3.79	0.92	4119.57	1.21	?
J2-6	24.5	50.5	25	0.02	0.076	3.79	0.95	3989.47	1.24	×
J2-7	22.2	47.8	30	0.02	0.076	3.79	1.01	3752.48	1.33	×
J2-8	30.8	59.2	10	0.02	0.094	4.69	1.15	4078.26	1.28	?
J2-9	26.5	53.5	20	0.02	0.094	4.69	3.87	1211.89	4.33	×
J4-1	28.9	56.1	15	0.04	0.125	3.13	1.76	1778.41	1.52	×
J4-2	26.5	53.5	20	0.04	0.125	3.13	1.71	1830.41	1.47	×
J4-3	33.5	61.5	5	0.04	0.152	3.79	2.13	1779.34	1.4	?
J4-4	26.5	53.5	20	0.04	0.152	3.79	9.51	398.53	6.24	×
J8-1	28.9	56.1	15	0.08	0.250	3.13	1.74	1798.85	0.75	×
J8-2	26.5	53.5	20	0.08	0.250	3.13	13.85	225.99	5.97	×
J8-3	24.5	50.5	25	0.08	0.250	3.13	3.41	917.89	1.47	×
J8-4	22.2	47.8	30	0.08	0.250	3.13	1.55	2019.35	0.67	×