METHOD FOR EVALUATING CRYSTAL GRAIN SIZE DISTRIBUTION OF POLYCRYSTALLINE SILICON, METHOD FOR SELECTING POLYCRYSTALLINE SILICON ROD, POLYCRYSTALLINE SILICON ROD, POLYCRYSTALLINE SILICON MASS, AND METHOD FOR PRODUCING SINGLE CRYSTALLINE SILICON

摘要

PROBLEM TO BE SOLVED: To provide a technique which contributes to such a case that polycrystalline silicon suitable as a raw material for producing single crystalline silicon is selected with high quantitative property and reproducibility and the single crystalline silicon is produced stably.SOLUTION: When a crystal grain size distribution of the polycrystalline silicon is evaluated, a collected disk-shaped sample 20 is disposed at such a position that Bragg reflection from the Miller index plane (hkl) is detected; the disk-shaped sample 20 is rotated in-plane around the center thereof at a rotation angle so that an X-ray irradiation range, which is defined by a slit, scans the principal plane of the disk-shaped sample 20; a chart showing the rotation angle () dependency of the disk-shaped sample 20 of the Bragg reflection intensity is obtained; a change amount of the diffraction intensity of a baseline of the scan/chart, which intensity is changed per a unit rotation angle, is calculated as a primary differential value; the distortion degree is calculated when a normal distribution curve of the absolute values of the change amounts is formed; and the polycrystalline silicon suitable as the raw material for producing the single crystalline silicon is selected by using the calculated distortion degree as an evaluation index of the crystal grain size distribution.