Semiconductor devices with align key structure for stack structures and data storage systems including the same

Abstract

Semiconductor devices may include a first stack structure including interlayer insulating layers and gate electrodes alternately stacked in a first direction perpendicular to an upper surface of a substrate on a first region of the substrate and including a first lower stack structure and a first upper stack structure, a second stack structure including the interlayer insulating layers and sacrificial insulating layers alternately stacked in the first direction on a second region of the substrate and including a second lower stack structure and a second upper stack structure, a channel structure penetrating the first upper stack structure and the first lower stack structure, extending in the first direction, and including a channel layer, and an align key structure penetrating the second lower stack structure and extending in the first direction. The second upper stack structure may include a first align key region on the align key structure.