CGSim software can be applied to modeling and optimization of silicon growth by Czochralski method including improvement of the hot zone design, recipe (time-dependent value of heater power, crystal rotation rate, crucible rotation rate, crystal pulling rate), effect of magnetic fields, optimization of the temperature ramp down schedule in the cooling phase. Most common objectives of the simulations are testing of the hardware modification, minimizing the probability of the crystalline structure loss, reduction of energy consumption, shortening of the growth cycle, increasing the process stability, achieving higher crystal quality in terms of residual stress and doping uniformity.

In case of 300 mm silicon, the influence of melt convection on the shape of the crystallization front is especially pronounced. Here, unlike Czochralski growth of smaller diameter Si ingots, heat and mass transfer is mostly governed by turbulent flow structures. Essential 3D features of the turbulent melt fluctuations, especially under the crystal, result in non-uniform heat supply into the crystallization front and, therefore, strongly non-uniform and unsteady crystallization rate distribution. These phenomena can be directly modeled in 3D unsteady analysis. 3D unsteady approach implemented in CGSim was successfully applied to simulate industrial Czochralski growth of 300 mm diameter silicon crystals, see [1, 2] for details.

Publications

[1] “Calculation of bulk defects in CZ Si growth: impact of melt turbulent fluctuations”, V.V. Kalaev, D.P. Lukanin, V.A. Zabelin, Yu.N. Makarov, J. Virbulis, E. Dornberger, W. von Ammon, J. Crystal Growth, 250/1-2 (2003) pp. 203-208.

[2] “Advances in the simulation of heat transfer and prediction of the melt-crystal interface shape in silicon CZ growth”, D.P. Lukanin, V.V. Kalaev, Yu. N. Makarov, T. Wetzel, J. Virbulis, and W. von Ammon, J. Crystal Growth, 266/1-3 (2004) pp. 20 – 27.