PURIFICATION OF METALLURGICAL SILICON FOR SOLAR-GRADE SILICON BY ELECTRON-BEAM BUTTON MELTING

被引:100
作者
IKEDA, T
MAEDA, M
机构
[1] Institute of Industrial Science, University of Tokyo, Minato-ku, Tokyo 106, Roppongi
关键词
SILICON; REFINING; ELECTRON BEAM; PHOSPHORUS; ALUMINUM; CALCIUM; CARBON; EVAPORATION; SOLAR CELL; SOLAR GRADE;
D O I
10.2355/isijinternational.32.635
中图分类号
TF [冶金工业];
学科分类号
0806 ;
摘要
Behavior of various impurities such as carbon, phosphorus, boron, calcium, aluminum, iron and titanium in metallurgical-grade silicon has been investigated during electron beam button melting with various modifications. Carbon, phosphorus, calcium and aluminum were removed by Electron Beam Remelting (EBR) treatment under 10(-2) Pa for 30 min. Ninety percent of carbon, 75% of aluminum, 89% of calcium and 93% of phosphorus was removed. The lowest content of these impurities were 15 ppmw C, 470 ppmw Al, 150 ppmw Ca and 3 ppmw P, respectively. First order rate equation was used for the removal of carbon, calcium and aluminum, and second order equation fit for the dephosphorization. Rate constants for calcium, aluminum and carbon ranged from 0.01 to 0.1 min-1. That of phosphorus was from 0.003 to 0.01 ppmw-1 . min-1.
引用
收藏
页码:635 / 642
页数:8
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