Carbon concentration and particle precipitation during directional solidification of multicrystalline silicon for solar cells

Lijun Liu, Satoshi Nakano, Koichi Kakimoto

Research output: Contribution to journalArticle

93 Citations (Scopus)

Abstract

The content and uniformity of carbon and silicon carbide (SiC) precipitates have an important impact on the efficiency of solar cells made of multicrystalline silicon. We established a dynamic model of SiC particle precipitation in molten silicon based on the Si-C phase diagram. Coupling with a transient global model of heat transfer, computations were carried out to clarify the characteristics of carbon segregation and particle formation in a directional solidification process for producing multicrystalline silicon for solar cells. The effects of impurity level in silicon feedstock and solidification process conditions on the distributions of substitutional carbon and SiC precipitates in solidified silicon ingots were investigated. It was shown that the content of SiC particles precipitated in solidified ingots increases markedly in magnitude as well as in space with increase in carbon concentration in silicon feedstock when it exceeds 1.26×1017 atoms/cm3. The distribution of SiC precipitates can be controlled by optimizing the process conditions. SiC precipitates are clustered at the center-upper region in an ingot solidified in a fast-cooling process but at the periphery-upper region for a slow-cooling process.

Original languageEnglish
Pages (from-to)2192-2197
Number of pages6
JournalJournal of Crystal Growth
Volume310
Issue number7-9
DOIs
Publication statusPublished - Apr 1 2008

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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