A semiconductor device is provided as follows. A peripheral circuit structure is disposed on a first substrate. A cell array structure is disposed on the peripheral circuit structure. A second substrate is interposed between the peripheral circuit structure and the cell array structure. The cell array structure includes a stacked structure, a through hole and a vertical semiconductor pattern. The stacked structure includes gate electrodes stacked on the second substrate. The through hole penetrates the stacked structure and the second substrate to expose the peripheral circuit structure. The vertical semiconductor pattern is disposed on the peripheral circuit structure, filling the through hole.