Oxygen '96
Early Stages of Oxygen Precipitation in Silicon
COMPUTER SIMULATION OF DEFECTS DISTRIBUTION FORMED DURING
CZ-Si CRYSTAL GROWTH
K. Kawakami (a), H. Harada (a), T. Iwasaki (a) and
R. Habu (b)
(a) Advanced Technology Research Labs., Nippon Steel Co., 3434
Shimata, Hikari 743, JAPAN
(b) SKY Aluminium Co.,Ltd, 1351
Uenodai, Fukaya 366, JAPAN
Keywords: oxygen, silicon, vacancy, interstitial, OSF, AOP.
The nuclei of ring-likely-distributed OSF (R-OSF) in CZ-Si are known
to have characteristics shown below. (1) The radius of the ring is
decreased with the decrease of the crystal pull rate. (2) The nuclei
are not formed when the pull rate is smaller than a critical rate
which is proportional to the axial temperature gradient at the
solid/liquid interface. (3) They are formed most likely at the top of
ingots. We calculated the distributions of point defects formed during
crystal growth based on the model that the distributions of vacancies
and self interstitials could be determined by taking their diffusion
and annihilation into account. The calculation results were compared
with experimental ones. We found that the R-OSF behaviour can be
explained by assuming that the concentrations of vacancies and self
interstitials are the dominant factors to control the nucleation. The
nucleation of anomalous oxygen precipitation (AOP), which is occurred
in crystals that are abruptly detached from the melt, can also be
explained by the same assumption.
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Last modified: Wed Mar 13 16:19:11 GMT 1996
JG
