Profile of impurities in polycrystalline silicon samples purified in an electron beam melting furnace

The photovoltaic properties of the polycrystalline silicon depend mainly on the crystalline structure (grain size and presence of defects) and of the purity of the material. The production of monocrystalline silicon for high-efficiency solar cells requires an extremely complex and expensive process. Therefore, the production of photovoltaic energy for terrestrial use, on a large scale, demands an alternative and low-cost method, especially in terms of purification of the starting material. The use of metallurgical grade silicon and the purifying of the same, through melting in electron beam furnace under a 10−3 Pa vacuum, is a method, which is able to provide high-purity material (99.999% Si). In this research, the results of the chemical analysis of polycrystalline silicon purified in an electron beam melting furnace, specially in terms of distribution of impurity due to their position in the sample related to the direction of solidification, are presented.