Removal of phosphorus contained in silicon by treatment vacuum

Abstract:

The demand for photovoltaic is increasing the rate of over 20% per year in the international Market in the last decade due to diversification program in the energy matrix. This study aims to investigate the removal of phosphorus by vacuum from metallurgical grade silicon (MGSi) (98.5% to 99%) to obtain the solar grade silicon (SGCi) (99.999% to 99.99999% Si) Experiments were carried out in vacuum induction furnace, varying parameters such as temperature, time and the area exposed to the vacuum/volume to molten silicon. The results of chemical analysis were obtained coupled plasma (ICP) and evaluated based on kinetic and thermodynamic aspects of the reaction of vaporization of the phosphorus in the silicon. The phosphorus was decreased from 33 to approximately 1,5 ppm P after three hours of vacuum treatment, concluding that phosphorus removal by vacuum is technically feasible.


Reference:
LOTTO, André Alexandrino; FERREIRA NETO, João Batista; MOURÃO, Marcelo Breda. Remoção de fósforo contido em silício por tratamento a vácuo. In: CONGREESO ANUAL DA ABM, 68., 2013, Belo Horizonte. Anais… 12 p.

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