We have investigated the origin of micropipe defects (MPs). 6H-SiC single crystals including MPs were grown at both conditions of normal and Si-added atmosphere. The MP densities (MPDs) were 0 cm(-2) and 22.5 cm(-2) for representative area of the crystals grown in normal and Si-added atmosphere, respectively. A new technique with the Vickers indenter was used to expose an inner surface of a MP for Auger electron spectroscopy analysis. The analysis revealed that no specific evidence for Si-droplet was found at the starting point of the MP in 6H-SiC single crystal that was grown in the Si-added atmosphere. Although a large number of small angle boundaries and screw dislocations were observed in the region around MPs even in a low MPD (similar to1 cm(-2)) crystal, screw dislocation density were similar to 6x10(2) cm(-2) in other region.