Numerical simulation of thermophysical performance's effect on sapphire crystal growth with SAPMAC method

Large size sapphire crystal growth with SAPMAC method is achieved by controlling the temperature gradient of system to control the whole growth process, and the values and distribution of temperature gradient in crystal and melt has the important effect on crystal growth. The thermophysical performance of crystal material also has great effect on heat transfer and temperature distribution in crystal and melt. The effect of thermophysical performance of material on crystal growth was simulated. The results show that smaller thermal conductivity can reduce the temperature gradient and interface convexity ratio effectively when the crystal and melt has the same conductivities; the bigger radial conductivity and smaller axial conductivity are convenient for keep the little interface convexity ratio; the effect of thermal capacity and heat of fusion on temperature distribution can be negligible. A high quality sapphire crystal was produced by choosing a axial as the orientation, whose diameter is as long as 230 mm.