The 6H-SiC single crystals were grown using a self-designed crystal grower by the sublimation method. The grown crystals were typically 30 mm in diameter and 10 mm in length. Optimum growth conditions were established as follows : the temperature of the raw material was $2150~2250^{circ}C$, the temperature of the substrate was $1950~2050^{circ}C$, the temperature difference between the raw material and substrate was about $200^{circ}C$, growth pressure was 50~200 torr and growth rate was 300~700 $mu extrm{m}$/hr. Optical microscopy was used for observing the surface of the 6H-SiC single crystal grown and the phenomenological approach was performed on the formation mechanism of the defects in the 6H-SiC crystal. Especially, the micropipes in the as-grown surface were examined to determine the formation mechanisms of the micropipes.