Effects of crystal rotation on the carbon transport in the top-seeded solution growth of SiC single crystal

Abstract

To achieve a high and uniform growth rate for the solution growth of silicon carbide (SiC), the fluid flow and carbon transport in the solution should be well estimated and controlled. The application of crystal rotation is effective in controlling the flow pattern and carbon transport in the SiC growth system. In this paper, the effects of crystal rotation on the solution flow, carbon concentration and growth rate for growing SiC crystals were numerically investigated by using a global heat and mass transfer model. The results indicated that crystal rotation strongly enhances the convection in the solution and makes the upward flow proceed deeper, resulting in the distribution of radial temperature along the growth interface turning from convex to concave towards the solution with the increase in the crystal rotation rate. Consequently, the carbon transport in the solution is strengthened, leading to an increase in the maximum value of the growth rate with a higher crystal rotation rate. However, the radial uniformity of the crystal growth rate along the growth interface becomes poor due to the hot solution moving upward to the center of the seed crystal with the increase in the crystal rotation rate. In the present study, it is found that the intensity of the forced convection vortex generated by an intermediate crystal rotation rate is beneficial to obtain a uniform distribution of growth rate and a relatively high growth rate.