Study of inhomogeneous radial distribution of defects in as-grown and annealed Czochralski Silicon crystals by multi-chroic infrared light scattering tomography

Multi-chroic infrared light scattering tomography (MC-IR-LST) and transmission electron microscopy (TEM) were used to systematically investigate the inhomogeneous radial distribution of defects in as-grown and annealed Czochralski silicon (CZ-Si) crystals. A new defect morphology of dark stripes observed for the first time by the MC-IR-LST system in a special region in the as-grown CZ-Si crystal. After annealing the crystal at 1150°C for 16 h in an O2 atmosphere, dark stripes that became scattered in width and deep in contrast were clearly visible in an OSF-ring area. The location of these stripes in the as-grown crystal coincided with that in the annealed CZ-Si crystal, where many stacking faults and oxygen-precipitate-related polyhedral defects were revealed by TEM analysis. This means that the dark stripes were generated during crystal growth as original grown-in defects. Quantitative measurement of the inhomogeneous radial distribution of defects in the annealed crystal was made and the characteristics of the defects in different regions of the crystal were analytically discussed.