THE EFFECTS OF PULLING RATES ON THE SHAPE OF CRYSTAL-MELT INTERFACE IN SI SINGLE-CRYSTAL GROWTH BY THE CZOCHRALSKI METHOD

The temperature profile and the shape of the crystal/melt interface in a Czochralski (CZ) furnace for large Si single crystal growth was sim ulated taking into consideration the fluid flow and surface radiationa l heat transfer. The view factors of the surface elements were calcula ted for radiation heat transfer. Two phases (crystal and melt) were tr eated as a continuous phase by assigning artificially large viscosity to the solid phase and the latent heat was accounted for by iterative heat evolution method, This simulation model of a CZ system was applie d to the growth process of a 6 inch Si single crystal to study the eff ects of pulling rates on the interface shape. It was found that the in terface becomes more concave to the melt as the crystal grows or as th e pulling speeds become higher, and that the interface height is linea rly dependent upon the pulling rate.