
124 Crystal Growth and Evaluation of Silicon for VLSI and ULSI
The crystals grown by the CZ method are slowly allowed to cool to room temperature
to avoid the creation of point defects. Fast cooling of crystal arrests many atomic move-
ments, and this may create randomness within the grown crystal, leading to many unex-
pected defects. Several studies have been carried out on the inuence of cooling conditions
and isotherm shapes within the grown crystals. Optimization of cooling conditions were
reported from time to time. Crystal cooling at this stage is one of the crucial issues to
terminating the crystal growth. References [297–302] provid