H. Machida et al., SPIRAL GROWTH OF RUTILE SINGLE-CRYSTAL BOULES IN THE EDGE-DEFINED, FILM-FED GROWTH-PROCESS, Journal of crystal growth, 137(1-2), 1994, pp. 82-85
Spiral growth of rutile crystal boules, obtained by the edge-defined,
film-fed growth (EFG) method, is analyzed using the results of radiati
ve spectral measurements of the die top during crystal growth. The obs
ervation of spiral growth is connected with the absorption of thermal
radiation in the growing crystal which shields the heat transfer from
the die top. In such a case, the temperature distribution on the dic t
op is largely dependent on the location of the growing crystal on the
die top. The meniscus tends to move to an area free from growing cryst
al on the die top. This results in an asymmetry of the temperature dis
tribution which is difficult to change and a spiral crystal results.