  Czochralski-grown boron-doped silicon crystals were studied by the techniques
of the low-angle mid-IR-light scattering and electron-beam-induced current. The
large-scale accumulations of electrically-active impurities detected in this
material were found to be different in their nature and formation mechanisms
from the well-known impurity clouds in a float zone-grown silicon. A
classifcation of the large-scale impurity accumulations in CZ Si:B is made and
point centers constituting them are analyzed in this paper. A model of the
large-scale impurity accumulations in CZ-grown Si:B is also proposed.
