Crystal Growth from the Melt

the long version

The bulk single crystals of semiconductors (e.g. Si, GaAs) and oxides which are at present commercially produced have mostly non-uniform properties in the microscale (e.g. doping striations) and in the macroscale (longitudinal and lateral segregation). Such inhomogeneities are deleterious for the performance of the devices produced from these crystals. This book gives a review of the various origins of inhomogeneities occuring during crystal growth. It is shown that convection is the major source of the non-uniformities in the technically used growth configurations, e.g. Czochralski-, zone- and Bridgman-methods, because the growth rate is controlled by the heat transport. The formalism of hydrodynamics, especially dimensionless numbers, is used for a modeling of melt growth, giving a correlation between the occurrence of inhomogeneities and relevant growth parameters. The results of the theoretical and experimental modeling are found to correlate with results of real crystal growth, especially for cases of dominating buoyancy convection. Various measures in avoiding inhomogeneities are derived from the models and are discussed with respect to their efficiency and practical applicability.