Density anomaly effect upon silicon melt flow during Czochralski crystal growth I. Under the growth interface

Abstract

Temperature fluctuations under the growth interface region were measured to evaluate the flow structure during the Czochralski silicon growth process. The impurities which influence the density anomaly of the silicon melt are doped as experimental parameters. The flow structure of this region was found to be basically a random one that is supposed to represent the “soft turbulence” induced by Rayleigh-Bénard convection. The addition of gallium to the melt changes the flow structure to a laminar-like one when the melt depth is shallow while the flow structure is still similar to a soft turbulence in the cases of boron-doped 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.