Stabilizing influence of the coriolis force during melt growth on a centrifuge

Abstract Results are presented of model experiments in a test cell and of numerical calculations simulating the influence of buoyancy-driven convection during crystal growth of semiconductors on a centrifuge. It is clearly demonstrated that the action of the Coriolis force causes two very different flow states (I, II), depending whether the rotation sense of the flow is in the same or opposite direction to that of the centrifuge. Type I is very similar to that normally observed on earth. Type II is only observed on the centrifuge and has a very large stability range of steady convection which can be used to grow striation-free crystals. The results of this paper give an excellent agreement between experiments and numerical modelling which finally leads to a fully satisfying explanation of the crystal growth results on a centrifuge observed in our group nearly ten years ago.