Some micropipes were dissociated into several closed-core screw dislocations during vapor phase epitaxy. Electrical properties of Ni-Schottky barrier diodes (SBDs) fabricated on the 4H-SiC epilayer containing continuous and dissociated micropipes were investigated based on current-voltage (I-V) characteristic curves. An improvement of reverse blocking performance by the micropipe dissociation was confirmed, because the continuous micropipe caused premature breakdown and the dissociated micropipe withstood up to 1000 to 2000 V. The wide variation of breakdown voltage was recognized not only in the SBDs including dissociated micropipe but also in SBDs without micropipe. Thus, significant lowering of the reverse blocking performance by the presence of the dissociated micropipe was not recognized.