Purification of crystalline layers by controlling the temperature gradient

The purification of the crystalline layers obtained in layer crystallizatio n has been carried out by a temperature gradient method. The effect of temp erature gradients on the migration of inclusions was studied. The effect of the structural configuration of the layers on the migration of inclusions was also explored. Impurity concentrations in the layers were obtained unde r variation of operating conditions such as the temperature gradient and co oling rate. The migration rate of inclusions and the impurity distribution obtained in the layer are modeled by a mass balance equation coupled with a n energy balance equation. The impurity distribution obtained by the model was verified with that which was obtained by the experiments. (C) 2001 Else vier Science B.V. All rights reserved.