Abstract: Provided is a wafer for solar cell which can be produced using a polycrystalline semiconductor wafer cut out using a bonded abrasive wire, which wafer can be used for manufacturing a solar cell with high conversion efficiency. In a wafer for solar cell before acid texturing of the present invention, produced from a polycrystalline semiconductor wafer cut out using a bonded abrasive wire, an amorphous layer does not exist, and irregularities caused due to the cutting using the bonded abrasive wire are left in at least one surface of the wafer for solar cell.

Abstract: Provided is a wafer for solar cell which can be produced using a polycrystalline semiconductor wafer cut out using a bonded abrasive wire, which wafer can be used for manufacturing a solar cell with high conversion efficiency. In a wafer for solar cell before acid texturing of the present invention, produced from a polycrystalline semiconductor wafer cut out using a bonded abrasive wire, an amorphous layer does not exist, and irregularities caused due to the cutting using the bonded abrasive wire are left in at least one surface of the wafer for solar cell.

Abstract: A solar cell wafer having a porous layer on a surface of a semiconductor wafer typified by a silicon wafer, which can further reduce reflection loss of light at the surface. A solar cell wafer 100 of the present invention has a porous layer 11 having a pore diameter of 10 nm or more and 45 nm or less, on at least one surface 10A of a semiconductor wafer 10, and the layer thickness of the porous layer 11 is more than 50 nm and 450 nm or less.

Abstract: Provided is a method of producing a wafer for a solar cell that can produce the solar cell with high conversion efficiency. A method of producing a wafer for a solar cell according to the present invention comprises a first step of contacting lower alcohol to at least one surface of the semiconductor wafer and a second step, after the first step, of contacting hydrofluoric acid containing metal ion to the at least one surface of the semiconductor wafer, and a third step that is, after the second step, a step of contacting alkali solution to the at least one surface of the semiconductor wafer, a step of contacting acid solution containing hydrofluoric acid and nitric acid to the at least one surface of the semiconductor wafer, or a step of carrying out an oxidation treatment to the at least one surface of the semiconductor wafer.

Abstract: Provided is a wafer for solar cell which can be produced using a polycrystalline semiconductor wafer cut out using a bonded abrasive wire, which wafer can be used for manufacturing a solar cell with high conversion efficiency. In a wafer for solar cell before acid texturing of the present invention, produced from a polycrystalline semiconductor wafer cut out using a bonded abrasive wire, an amorphous layer does not exist, and irregularities caused due to the cutting using the bonded abrasive wire are left in at least one surface of the wafer for solar cell.

Abstract: Mirror-polishing a front surface of a silicon wafer using polishing liquid composed of an abrasive grain-free alkaline solution including water-soluble polymers simplifies a polishing process, thus leading to an increase in productivity and a reduction in cost, and reduces the density of LPDs attributable to processing and occurring in the front surface of a mirror-polished wafer, thus improving the surface roughness of the wafer front surface.

Abstract: The method for producing a silicon epitaxial wafer according to the present invention has: a growth step F at which an epitaxial layer is grown on a silicon single crystal substrate; a first polishing step D at which, before the growth step, at least a front surface of the silicon single crystal substrate is polished without using abrasive grains; and a second polishing step G at which at least the front surface of the silicon single crystal substrate is subjected to finish polishing after the growth step.

Abstract: Provided is a method of producing a wafer for a solar cell that can produce the solar cell with high conversion efficiency. A method of producing a wafer for a solar cell according to the present invention comprises a first step of contacting lower alcohol to at least one surface of the semiconductor wafer and a second step, after the first step, of contacting hydrofluoric acid containing metal ion to the at least one surface of the semiconductor wafer, and a third step that is, after the second step, a step of contacting alkali solution to the at least one surface of the semiconductor wafer, a step of contacting acid solution containing hydrofluoric acid and nitric acid to the at least one surface of the semiconductor wafer, or a step of carrying out an oxidation treatment to the at least one surface of the semiconductor wafer.

Abstract: A solar cell wafer having a porous layer on a surface of a semiconductor wafer typified by a silicon wafer, which can further reduce reflection loss of light at the surface. A solar cell wafer 100 of the present invention has a porous layer 11 having a pore diameter of 10 nm or more and 45 nm or less, on at least one surface 10A of a semiconductor wafer 10, and the layer thickness of the porous layer 11 is more than 50 nm and 450 nm or less.

Abstract: Mirror-polishing a front surface of a silicon wafer using polishing liquid composed of an abrasive grain-free alkaline solution including water-soluble polymers simplifies a polishing process, thus leading to an increase in productivity and a reduction in cost, and reduces the density of LPDs attributable to processing and occurring in the front surface of a mirror-polished wafer, thus improving the surface roughness of the wafer front surface.

Abstract: An object of the present invention is to provided a wafer exhibiting excellent surface properties, in which variation in reaction, which has been concerned in surface treatment with a diffusion controlled process such as conventional wet treatment, is effectively suppressed in a method for surface treatment of a wafer involving a chemical treatment. Provided is a method for surface treatment of a wafer involving a chemical treatment, the chemical treatment including a reaction controlled process, and a diffusion controlled process following the reaction controlled process.

Abstract: The method for producing a silicon epitaxial wafer according to the present invention has: a growth step F at which an epitaxial layer is grown on a silicon single crystal substrate; a first polishing step D at which, before the growth step, at least a front surface of the silicon single crystal substrate is polished without using abrasive grains; and a second polishing step G at which at least the front surface of the silicon single crystal substrate is subjected to finish polishing after the growth step.

Abstract: After a water film is formed on a wafer front surface in a chamber, the water film is supplied sequentially with an oxidizing component of an oxidation gas, an organic acid component of an organic acid mist, an HF component of an HF gas, the organic acid mist, and the oxidizing component of the oxidation gas. As a result, the HF component and the organic acid component provide cleaning effect on the wafer surface, and a concentration of the cleaning components in the water film within a wafer surface can be even.

Abstract: A silicon oxide film on a wafer front surface, including on internal surfaces of pits, is removed by hydrogen fluoride gas. The pits are thus completely filled with a film growth component at a time of epitaxial film growth. Thereby, productivity is not reduced; wafer flatness is enhanced; and micro-roughness of the wafer front surface is improved.

Abstract: After a water film is formed on a wafer front surface in a chamber, the water film is supplied sequentially with an oxidizing component of an oxidation gas, an organic acid component of an organic acid mist, an HF component of an HF gas, the organic acid mist, and the oxidizing component of the oxidation gas. As a result, the HF component and the organic acid component provide cleaning effect on the wafer surface, and a concentration of the cleaning components in the water film within a wafer surface can be even.

Abstract: A silicon wafer cleaning method, comprising a first cleaning process, in which, after completion of mirror polishing of the surface, the silicon wafer is immersed in a non-ionic surfactant aqueous solution; a second cleaning process, in which the wafer, after completion of the first cleaning process, is immersed in a dissolved-ozone aqueous solution; and, a third cleaning process, in which the wafer, after completion of the second cleaning process, is immersed in an aqueous solution containing ammonia and hydrogen peroxide; and in which the processes are performed in succession.

Abstract: A silicon wafer cleaning method, comprising a first cleaning process, in which, after completion of mirror polishing of the surface, the silicon wafer is immersed in a non-ionic surfactant aqueous solution; a second cleaning process, in which the wafer, after completion of the first cleaning process, is immersed in a dissolved-ozone aqueous solution; and, a third cleaning process, in which the wafer, after completion of the second cleaning process, is immersed in an aqueous solution containing ammonia and hydrogen peroxide; and in which the processes are performed in succession.

Abstract: A method for analyzing impurities present in a silicon substrate. The method includes the steps of accommodating a silicon substrate resting on a support, and a solution for decomposing a silicon substrate which comprises a mixture of hydrofluoric acid, nitric acid and sulfuric acid, in an air-tight reaction vessel, in such a way as to keep the silicon substrate from directly contacting with the decomposing solution; allowing the decomposing solution to vaporize, thereby causing the substrate to decompose through vapor-phase reaction for sublimation, without heating or pressurizing the reaction vessel; and recovering the residue left by the decomposed substrate, to analyze the impurities contained in the substrate. This method makes it possible to determine the content of impurities that are present in a silicon substrate extremely precisely in a comparatively short time by decomposing the substrate through vapor-phase reaction without resorting to heating or pressurization.

Abstract: The method of this invention for analyzing impurities present in a silicon substrate comprises the steps of accommodating a silicon substrate resting on a support, and a solution for decomposing a silicon substrate which comprises a mixture of hydrofluoric acid, nitric acid and sulfuric acid, in an air-tight reaction vessel, in such a way as to keep the silicon substrate from directly contacting with the decomposition solution; allowing the decomposing solution to vaporize, thereby causing the substrate to decompose through vapor-phase reaction for sublimation, without heating or pressurizing the reaction vessel; and recovering the residue left by the decomposed substrate, to analyze the impurities contained in the substrate. This method makes it possible to determine highly precisely the content of impurities present in a silicon substrate in a comparatively short time by decomposing the substrate through vapor-phase reaction without resorting to heating or pressurization.