Method for evaluating degree of crystal orientation in polycrystalline silicon, selection method for polycrystalline silicon rods, and production method for single crystal silicon

Abstract

When a plate-like sampleextracted from a polycrystalline rod is evaluated, peaks can appear in a φ-scanning chart. The smaller the number of such peaks, and the narrower the half-value width of the peak, the more suitable the polycrystalline silicon rod is as a raw material for producing single-crystal silicon. It is preferable that the number of peaks in the φ-scanning chart is, for both the Miller index planes <111> and <220>, equal to or smaller than 24/cmwhen converted into unit per area of the plate-like sample. It is also preferable that the value obtained by multiplying the peak half-value width by δL=2πR/360, where Ris the radius of the sample, is defined as an inhomogeneous crystal grain size, and that a polycrystalline silicon rod of which all the inhomogeneous crystal grain sizes are smaller than 0.5 mm is selected as a raw material for producing single-crystal silicon.