Two kinds of diffuse x-ray scattering were found in a very perfect silicon single crystal. One of them forms a cigar shape, extending along the [111] direction. The other is a disk shape whose normal is also parallel to the [111] direction in reciprocal space. Both diffuse scatterings are predominant along the crystal pulling [111] direction. From simple Fourier inversion of the shapes of the diffuse scatterings, it is concluded that the platelike defects and needlelike defects are the origins of the diffuse scatterings. The platelike defects observed differ from those observed by Patel for Czochralski silicon with heat treatment.

Two kinds of diffuse x-ray scattering due to defects were observed from a very perfect silicon single crystal. One forms the shape of a cigar, elongated along the [111] direction, and the other is a disk, which is broad and perpendicular to the [111] direction. The cigar-shaped diffuse scattering is asymmetric around the 111 relp with respect to the Bragg peak. Fourier transforms reveal two types of defects; platelike defects [200 Å (φ) ×30 Å (t)] of vacancy type and needlelike defects (400 A (l)). The platelike defect dimensions are in fairly good agreement with those of B-swirl defects observed by de Kock et al. The platelike defects also have a close correlation with the crystal pulling direction. They are contained predominantly in the (111) planes for a crystal grown along the [111] direction.