V.I.Goriletsky
Received September 25, 1998
The causes of diameter variations of the crystal being grow
by Kyropolous method have been considered at the initial stage of
longitudinal crystal growth with automated mass control of the crystallizing
melt. It has been shown that when crystals over 300 mm diameter
are grown, the local changes of the front shape are the main cause
of considerable diameter variations. There changes are due to jump-like
changes of heat-exchange conditions between the crystal surface and
the environment, and those, in turn, result in structural, optical
and other defects in the crystal. The technique for process control
to prevent the above-mentioned effect is proposed. A particular case
of single crystal growing without pulling from melt is described (automated
method by Kyropolous).