We present 3D unsteady analysis of melt turbulent convection coupled with heat transfer in the crystal and crucible during 300 mm CZ Si crystal growth. The 3D analysis includes the calculation of the crystallization front geometry, validated by comparing to experimental data and results obtained with a conventional 2D model. At the second step, an analysis of defect incorporation and evolution in the crystal has been performed within a 2D model. (C) 2002 Elsevier Science B.V. All rights reserved.