A vertical semiconductor device includes; a pattern structure including a plurality of insulation patterns and a plurality of gate electrodes that are alternately and repeatedly stacked on a substrate, wherein the pattern structure includes a first gate electrode serving as a gate electrode of an erase transistor, wherein the first gate electrode is one of the plurality of gate electrodes; and a channel structure in a channel hole passing through the pattern structure, wherein the channel structure includes a data storage structure, a first channel, an undoped semiconductor liner, a doped semiconductor pattern, a filling insulation pattern and a capping pattern, wherein the data storage structure, the first channel, the undoped semiconductor liner, and the doped semiconductor pattern are sequentially disposed on a sidewall of the first gate electrode.