Oxygen distribution on a multicrystalline silicon ingot grown from upgraded metallurgical silicon

被引:23
作者
Di Sabatino, M. [1 ,2 ]
Binetti, S. [3 ]
Libal, J. [3 ]
Acciarri, M. [3 ]
Nordmark, H. [2 ]
Ovrelid, E. J. [2 ]
机构
[1] Norwegian Univ Sci & Technol NTNU, Dept Mat Sci & Engn, NO-7491 Trondheim, Norway
[2] SINTEF Mat & Chem, NO-7465 Trondheim, Norway
[3] Univ Milano Bicocca, UNIMIB, Dept Mat Sci, I-20125 Milan, Italy
关键词
Silicon; Oxygen; Feedstock; Defects; Lifetime;
D O I
10.1016/j.solmat.2010.09.013
中图分类号
TE [石油、天然气工业]; TK [能源与动力工程];
学科分类号
0807 ; 0820 ;
摘要
Oxygen precipitation creates centers of recombination of carriers. Therefore, oxygen concentration and its chemical configuration must be controlled. In this study, the oxygen distribution on a multicrystalline silicon ingot produced by directional solidification of upgraded metallurgical silicon is investigated. The highest amount of oxygen was detected close to the bottom of the ingot. Most of the oxygen present was interstitial but there were approximately 5-10 ppma oxygen present as precipitates. FT-IR and TEM confirmed the presence of many oxygen precipitates, mainly segregated at grain boundaries and dislocations. Lifetime measurements by QSSPC were performed on as grown- and passivated wafers, and after P-gettering. A correlation between the lifetime values and the presence of oxygen precipitates has been found and it has been shown that the electrical properties could be improved if an appropriate annealing step would be applied. Oxygen content may dramatically reduce the solar cell performances and efficiencies (estimated reduction of 1-3% absolute values). (C) 2010 Elsevier B.V. All rights reserved.
引用
收藏
页码:529 / 533
页数:5
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