Method for evaluating crystallinity of polycrystalline silicon

Abstract

The present invention involves: positioning a collected plate-shaped specimen (20) in a position where a Bragg reflection from a first Miller index surface <h1k1l1> is detected; in-plane rotating the plate-shaped specimen (20) at a rotation angle (phi) with the center of the plate-shaped specimen (20) as the center of rotation in a manner such that the x-ray-irradiation region delimited by a slit phi-scans the principal surface of the plate-shaped specimen (20); obtaining a chart expressing the rotation-angle (phi) dependency of the plate-shaped specimen (20) of the Bragg reflection intensity from the Miller index surface <hkl>; obtaining a baseline diffraction intensity value (IB) from the chart; similarly obtaining a baseline diffraction intensity value (IB 2) from a phi-scan chart obtained from a second Miller index surface <h2k2l2>; and using the magnitude correlation between the IB 1 value and the IB 2 value as the evaluation indicator of the crystallinity of polycrystalline silicon.

Description

technical field [0001] The present invention relates to a method of evaluating the crystallinity of polycrystalline silicon by an X-ray diffraction method, and a method of selecting a polycrystalline silicon rod or a polycrystalline silicon block suitable as a raw material for stably producing single crystal silicon using the method. Background technique [0002] Monocrystalline silicon, which is indispensable in the manufacture of semiconductor devices, etc., is grown by the CZ method and the FZ method, and polycrystalline silicon rods and polycrystalline silicon blocks are used as raw materials at this time. Such polysilicon materials are often produced by the Siemens method (see Patent Document 1 and the like). The Siemens method refers to a method in which silane raw material gases such as trichlorosilane and monosilane are brought into contact with a heated silicon core wire, thereby depositing polysilicon on the surface of the silicon core wire by CVD (Chemical Vapor D...

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Problems solved by technology

[0004] In addition, in Patent Document 2, in the process of manufacturing polycrystalline silicon rods (polycrystalline silicon rods, polycrystalline silicon rods) by the Siemens method, needle-like crystals may be precipitated in the rods, and single crystal silicon rods are produced by the FZ method using the polycrystalline silicon rods. During the cultivation, it was pointed out that there was a problem that the melting of each crystallite was dependent on its size, so that it could not be melted uniformly, and the unmelted crystallites passed through the melting region in the form of solid particles to the single crystal rod, so that the unmelted particles form is introduced into the solidification plane of the single crystal, thereby causing defect formation

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