Semicrystalline material from metallurgical grade silicon

A functional approach to producing solar cell material from metallurgical grade Si is presented as a means to producing polycrystalline cells of acceptable efficiencies without costly, separate purification steps. Grain boundaries were found to be generally absent from cells manufactured from mixtures of metallurgical grade Si and semiconductor grade Si. It was concluded that impurities were sinking into the grain boundaries, and acceptable cells could be produced without expensive chemical refinement techniques. The Simultaneously Present Large Impurity Technology (SPLIT) program was initiated to deal with cells with high impurity contents. Current construction of an Si feedstock plant to produce 1000 tons of metallurgical grade Si is noted.