DENSITY ANOMALY EFFECT UPON SILICON MELT FLOW DURING CZOCHRALSKI CRYSTAL-GROWTH .1. UNDER THE GROWTH INTERFACE

Temperature fluctuations under the growth interface region were measur ed to evaluate the flow structure during the Czochralski silicon growt h process. The impurities which influence the density anomaly of the s ilicon melt are doped as experimental parameters. The flow structure o f this region was found to be basically a random one that is supposed to represent the ''soft turbulence'' induced by Rayleigh-Benard convec tion, The addition of gallium to the melt changes the flow structure t o a laminar-like one when the melt depth is shallow while the flow str ucture is still similar to a soft turbulence in the cases of boron-dop ed and undoped at the same melt depth. These results suggest that the density anomaly of the silicon melt influences the melt flow structure of this region.