Suppression of the surface roughness by adjusting the temperature distribution in the top-seeded solution growth of SiC crystal.

Spontaneous nucleation of SiC particles and giant macroscopic steps result in the surface roughness of the grown crystal for the top-seeded solution growth of SiC crystal. To suppress the surface roughness, the temperature gradient was carefully adjusted by changing the relative position of the crucible and induction coils. The numerical simulation and experimental results show that the surface morphology of the grown crystal becomes smoother and there are fewer spontaneous nucleation particles attached to the growth surface with the decrease in the relative crucible position, due to the increase of temperature at the entire solution surface and the reducing of temperature gradient near the growth surface. Accordingly, a lower temperature gradient, a larger solution velocity, a higher carbon concentration, and a smaller carbon supersaturation near the growth surface can be obtained when the relative position between the crucible and the induction coil is 70 mm, which is demonstrated to be the most favorable for the elimination of spontaneous nucleation of small SiC particles and suppressing surface roughening with the full width at half maximum (FWHM) of 37.5 arcsec of 4H-SiC crystals.