Plane-wave synchrotron x-ray topography observation of grown-in microdefects in a slowly pulled CZ-silicon crystal

Abstract

Plane-wave x-ray topography was used to characterize grown-in defects in silicon crystals grown by the Czochralski method at a slow speed. The 220 reflection rocking curves of the sample crystal were measured in a symmetric Laue case. Oscillatory profiles were clearly observed in the rocking curves and were in good agreement with those calculated from the dynamical theory of x-ray diffraction. Images of the grown-in defects were observed in the plane-wave x-ray topographs of the 220 reflection. The density of the defects was determined as 300 cm−3. The lattice strain around the defects was evaluated as 10−6 from the dependence of the defect image contrast on the x-ray incident angles. The defect images are discussed using a grown-in defect model of entangled dislocation loop clusters.