Calculations are performed with an integrated process model for Czochralski oxide growth in which internal radiative heat transfer through the crystal is approximated. For the first time, melt/crystal interfaces are predicted which are deeply convex toward the melt and similar in shape to those observed experimentally. These results provide additional support for the importance of internal radiation in these systems. The inversion of these deep interfaces is also examined as a function of forced and natural convection in the melt. Finally, a new mechanism for the onset of crystal spiraling is postulated from observations of superheated crystal regions in some calculations.