Abstract: Silicon platelets essentially free of iron are precipitated from a solution of metallurgical grade silicon in molten aluminum and are melted in contact with silica slag to produce a refined metallurgical silicon (RMS). By directionally solidifying the refined silicon-slag melt, a directionally solidified refined metallurgical silicon (DS/RMS) is separated from a region of solidified melt having a high concentration of impurities rejected by the silicon as it solidifies. The resulting RMS and DS/RMS materials are low-cost, multigrained products having a substantially higher impurity content than in conventional high purity semiconductor grade silicon while, at the same time, have suitable properties for desirable solar cell and other silicon applications.

Abstract: Silicon platelets essentially free of iron are precipitated from a solution of metallurgical grade silicon in molten aluminum and are melted in contact with silica slag to produce a refined metallurgical silicon (RMS). Multigrained boules of said RMS are pulled by the Czochralski method on a rotating silicon seed rod from a melt of said RMS. Alternatively, the silicon-slag melt can be directionally solidified to produce a directionally solidified refined metallurgical silicon (DS/RMS) separated from a region of solidified melt having a high concentration of impurities rejected by the silicon as it solidifies. Multigrained DS/RMS boules are pulled from a melt of said DS/RMS. Alternatively, the DS/RMS is remelted and directionally solidified a second time with single crystal DS/RMS boules being pulled from a melt of the twice directionally solidified material.

Abstract: Silicon platelets essentially free of iron are precipitated from a solution of metallurgical grade silicon in molten aluminum and are melted in contact with silica slag to produce a refined metallurgical silicon. The silicon-slag melt solidified in a unidirectional manner so as to directionally solidify said silicon. A directionally solidified refined metallurgical silicon (DS/RMS) ribbon is pulled from a melt of the thus-refined silicon. This DS/RMS ribbon is a low-cost product having a substantially higher impurity content level than in conventional high purity semiconductor grade silicon while, at the same time, being useful for solar cell applications.

Abstract: Epitaxial and diffusion-type planar diodes and solar cells utilize low-cost refined metallurgical silicon substrates having a substantially higher impurity content than conventional high-cost, high purity semiconductor grade silicon. The epitaxial type products have an n-on-p-on-p substrate configuration, while the diffusion-type products have pentavalent impurities diffused therein to form a p-n junction in the low cost silicon substrate. One embodiment employs a multigrained refined metallurgical silicon (RMS) prepared by precipitating essentially iron-free silicon platelets from a solution of metallurgical grade silicon in molten aluminum, melting said refined platelets, in contact with a silica slag and pulling silicon boules from a melt of said refined metallurgical silicon (RMS).