Thermal stress inhibition in double crucible Czochralski large diameter crystal growth

In this paper we consider the problem of thermal stress inhibition in double crucible Czochralski crystal growth by means of a thermal tube with linear temperature distribution computationally determined from solution with adiabatic boundary condition, which provides the formation of a stressless one-dimensional temperature distribution along the growing crystal. We study how this linear temperature distribution applied along the thermal tube is “transferred” into the growing crystal depending on the gap between crystal and inner tube surfaces, within which complex radiative-convective heat transfer takes place. Calculations presented in the paper suggest that linear temperature distribution along the thermal tube allows an order of magnitude stress reduction in 80-100 mm diameter crystals of LiNbO3