Study on silicon melt convection during the RF-FZ crystal growth process I. experimental flow visualization

Silicon melt convection during the floating zone (FZ) crystal growth proces s under radio-frequency (RF) heating has been observed directly by using an X-ray radiography system with particle tracking velocimetry (PTV) in order to investigate the effect of the RF-induced electromagnetic field on the s ilicon melt convection. The result reveals that the silicon melt convection is fully affected by the RF induced electromagnetic field and the directio n of convection becomes opposite to the natural convection. The obtained ma ximum velocity was 0.1 m/s which was 4-5 times higher than CZ system and th e velocity field is fluctuated randomly. This will probably cause strong st riation in the crystal. (C) 1999 Elsevier Science B.V. All rights reserved.