Convection in a Czochralski crucible - Part 1: non-rotating crystal

摘要

A Czochralski melt is simulated in a model experiment and by numerical analysis. We use a transparent fluid (0.65 cSt silicone oil with Pr-6.8) which is contained in a transparent sapphire crucible (40 mm inner diameter, 40 mm height, crystalline material). A copper rod(e.g.14 diameter) is used to simulate the growing crystal. An imposed temperature difference between the crucible and the crystal dummy gives rise to convective flow in the fluid. Forced convection by crystal rotation has also been applied but will be treated in part 2 of this paper. Our experiment models to a good degree the growth of oxide and fluoride crystals from noble metal crucibles. Flow visualization and flow velocity measurements are performed. We report the flow patterns observed in the fluid for different parameters (temperature difference. Fluid depth, meniscus, free surface cooling.