Abstract: In a crystalline silicon formation apparatus, a quick cooling method is applied to the bottom of a crucible to control a growth orientation of a polycrystalline silicon grain, such that the crystal grain forms twin boundary, and the twin boundary is a symmetric grain boundary, and the crystal grain is solidified and grown upward in unidirection to form a complete polycrystalline silicon, such that defects or impurities will not form in the polycrystalline silicon easily.

Abstract: In slicing a crystal bar into silicon wafers, an average about 40% of silicon would be loss due to the widths of slicing wires themselves. The fact that the silicon slurry is discarded as sludge or discarded after recovering silicon carbide particles causes a large waste of cost. If the silicon slurry (40% of silicon) could be recovered as the raw material for growing silicon crystal bars, the production cost would be lowered. The recovery method of silicon slurry according to the present invention could effectively obtain silicon raw material after removing impurities, which could recover the raw material used in solar crystals, further capable of increasing the silicon crystal production and lowering the cost.

Abstract: In slicing a crystal bar into silicon wafers, an average of about 40% of silicon would be loss due to the widths of slicing wire saws themselves. The fact that the silicon slurry is discarded or discarded after recovering silicon carbide particles causes a large waste of cost. According to the present invention, the silicon slurry undergoes an acid washing step and a high temperature separation step, wherein the heating temperature is between the melting points of silicon and silicon carbide, and the silicon slurry is resident for an appropriate time, such that the silicon and silicon carbide would be separated to obtain silicon. The present invention could recover the raw material used in solar crystals, further capable of increasing the silicon crystal production and lowering the cost.

Abstract: A method and construction of growing wafer ingot by having a thermal shield disposed on an opening of a crucible, an opening approximating a polygonal contour disposed on the thermal shield to control gas current, heat conduction and heat radiation in ingot growth, an isotherm of condensation temperature in ingot growth approaching a polygonal form to grow the ingot into a form approximating the preset sectional form of a polygon for minimizing the material to be cut off in the subsequent process of slicing wafer ingot into chips.