PRODUCTION OF HIGH PURITY SILICON FOR SOLAR CELL WITH THREE-LAYER PROCESS METHOD

摘要

At present, polysilicon with 99.9999% purity has been used to solar cell raw. The traditional method of producing polysilicon is improved SIEMENS method. In this paper, the authors explored a new molten salt electrolysis method for purifying industrial silicon. Electrolytic process for purifying the industrial silicon was called the three-layer process, in which silicon is refined from a lower anodic molten layer of impure silicon, via an intermediate electrolyte layer of molten salts, to a top cathodic layer of pure silicon. The electrolytic process was carried out at temperature 1450-1500°C. The industrial silicon fed into the cell may be electrolytically refined to high purity silicon but impurities as Al, Fe, Ca, B, P decreased obviously with ICP-AES test.