METHOD FOR EVALUATING CRYSTAL GRAIN SIZE DISTRIBUTION OF POLYCRYSTALLINE SILICON

摘要

The method comprises following steps; a collected disk sample (20) is disposed at a position where Bragg reflection from a Miller index plane is detected; the disk sample (20) is rotated in-plane about the center thereof by a rotation angle φ so that an X-ray irradiation region defined by a slit φ-scans the principal plane of the disk sample (20); a chart showing the dependence of intensity of the Bragg reflection on the rotation angle (φ) of the disk sample (20) is determined; the amount of change per a unit rotation angle of diffraction intensity of a baseline of the φ scan chart is determined as a first derivative value; skewness in the normal distribution of the absolute value of the amount of change is calculated; and the skewness is used as an evaluation index of the crystal grain size distribution to select polycrystalline silicon.

主权项

1. A method for evaluating crystal grain size distribution of polycrystalline silicon by an X-ray diffraction method, the method comprising:
preparing a plate sample of the polycrystalline silicon; disposing the plate sample at a position where Bragg reflection from a Miller index plane is detected; rotating the plate sample in-plane about the center thereof by a rotation angle φ so that an X-ray irradiation region defined by a slit φ-scans a principal plane of the plate sample; determining a φ scan chart showing the dependence of intensity of the Bragg reflection from the Miller index plane on the rotation angle (φ) of the plate sample; determining the amount of change per a unit rotation angle of diffraction intensity of a baseline of the φ scan chart as a first derivative value; calculating skewness in the normal distribution of the absolute value of the amount of change by the following equation:b=n∑i=1n(xi-x_s)3(n-1)(n-2)[Expression1] wherein n represents the number of data; s represents standard deviation; xi represents the i-th data; and x bar represents an average value; and using the skewness (b value) as an evaluation index of the crystal grain size distribution.