Abstract: Provided is a process for producing a boron added silicon (purified silicon) in an energy saving mode from a reduced silicon obtained by reducing a silicon halide with a metal aluminium. The production process of the invention comprises reducing a silicon halide with a metal aluminium to give a reduces silicon, heating and melting the resulting reduced silicon, and adding boron thereto followed by solidification for purification under the condition of a temperature gradient provided in one direction in a mold. Preferably, after washed with an acid, the reduced silicon is heated and molten, and boron is added thereto. After the reduced silicon is heated and molten under reduced pressure, boron is added thereto. After heated and molten, the reduced silicon is purified by solidification in one direction, then heated and molten, and thereafter boron is added thereto.

Abstract: It is an object of the present invention to provide aluminum-containing silicon for n-type solar cells. It further provides a method of producing phosphorous-doped silicon refined form aluminum-containing silicone from an economical point of view. It provides silicon for n-type solar cells containing aluminum at a mass concentration of from 0.001 to 1.0 ppm and phosphorous at a mass concentration of from 0.0011 to 1.1 ppm, and having a mass concentration ratio of phosphorous to aluminum of 1.1 or greater. It further provides a method of producing phosphorous-doped silicon, including: preparing a melted mixture containing aluminum, phosphorous, and silicon, by heating and melting aluminum-containing silicon to obtain a melted product and adding phosphorous to the obtained melted product, or by adding phosphorous to aluminum-containing silicon to obtain a mixture and heating and melting the obtained mixture; and then solidifying the melted mixture in a mold under a temperature gradient in one direction.

Abstract: It is possible to efficiently obtain a purified material from a material containing a metalloid element such as silicon or metal element as the main component, and an impurity. The method for purifying a material, comprising bringing a material containing a metalloid element or metal element as the main component, and an impurity into contact with a compound represented by the following formula (1): AlX3 ??(1) wherein X is a halogen atom; to remove the impurity from the material.

Abstract: A standard temperature gradient (T0) and a standard solidification rate (R0) which meet the formula (1) are determined in advance based on C10max and Y0. k=[K1×Ln(R0)+K2]×[K3×exp[K4×R0×(K5×C2+K6)]]×[K7×T0+K8]?K9 (1) wherein k represents a coefficient selected from a range from 0.9 time to 1.1 times an aluminum effective distribution coefficient (k?) so measured as to meet the formula (2): C10max=k?×C2×(1?Y0)k?-1 (2) wherein k? represents analuminum effective distribution coefficient; C2 represents the concentration of aluminum in a silicon molten solution raw material.

Abstract: Provided is a process for producing a boron added silicon (purified silicon) in an energy saving mode from a reduced silicon obtained by reducing a silicon halide with a metal aluminium. The production process of the invention comprises reducing a silicon halide with a metal aluminium to give a reduces silicon, heating and melting the resulting reduced silicon, and adding boron thereto followed by solidification for purification under the condition of a temperature gradient provided in one direction in a mold. Preferably, after washed with an acid, the reduced silicon is heated and molten, and boron is added thereto. After the reduced silicon is heated and molten under reduced pressure, boron is added thereto. After heated and molten, the reduced silicon is purified by solidification in one direction, then heated and molten, and thereafter boron is added thereto.

Abstract: Provided is a process for producing a purified silicon by cutting off a crude silicon region, without determining the aluminium concentration in a directionally-solidified silicon. In the process of the invention, a standard solidification fraction (f0) satisfying the following formula (1) and formula (2) is obtained from the predetermined maximum level of aluminium concentration (C10max), the temperature gradient (T) and the solidification speed (R), and the directionally-solidified silicon is cut at the part having a solidification fraction (f) in the solidification step corresponding to f0. k = { K 1 × Ln ? ( R ) + K 2 } × { K 3 × exp ? [ K 4 × R × ( K 5 × C 2 + K 6 ) ] } × { K 7 × T + K 8 } - K 9 ( 1 ) [wherein k is a coefficient selected from a range of from 0.9 times to 1.