DIRECT OBSERVATION OF MARANGONI CONVECTION-INDUCED OSCILLATION AT SILICON MELT SURFACE

Marangoni convection-induced oscillation at the molten silicon surface of a half-zone liquid column was directly observed using real-time moire phase-shift interferometry. The oscillation frequency was analyzed by applying the Fourier transformation to the data of relative displacement versus time relationship of the melt surface. Several peaks of oscillation frequencies were observed at 0.5–5 Hz, being higher than the frequencies at 0.1–0.3 Hz observed in the previous studies by the temperature measurement using thermocouples and the x-ray flow visualization technique.