OXYGEN-TRANSFER DURING SINGLE SILICON CRYSTAL-GROWTH IN CZOCHRALSKI SYSTEM WITH VERTICAL MAGNETIC-FIELDS

Oxygen transfer in silicon melts during crystal growth under vertical magnetic fields is investigated numerically and experimentally. A thre e-dimensional numerical simulation, including melt convection and oxyg en transport, is carried out to understand how oxygen transfers in the melt under magnetic fields. Oxygen concentrations in single silicon c rystals grown from the melt under these magnetic fields are experiment ally measured by using on infrared absorption technique. The results o btained are compared to results from a numerical simulation. An anomal ous increase is observed in the oxygen concentration of the grown crys tals under a magnetic field of about 0.03 T. The cause of this anomaly is identified as Benard instability, since the temperature at the bot tom of the crucible is higher than that at interface. When the tempera ture at the bottom is decreased, the Benard cell can be removed, and a monotonic decrease in the oxygen concentration in the single silicon crystals can be observed.