Abstract: A semiconductor device includes a stack structure including mold layers and horizontal conductive layers, which are alternately stacked. A channel structure vertically extending in the stack structure is provided. A pillar structure vertically extending in the stack structure is provided. A contact plug connected to a corresponding one of the horizontal conductive layers is disposed. The pillar structure includes a pillar extending through the horizontal conductive layers, and extensions protruding from a side surface of the pillar. Each extension is horizontally aligned with a corresponding one of the horizontal conductive layers.

Abstract: A semiconductor device including a peripheral circuit layer on a substrate; a lower stack and upper stack on the substrate; a stopper layer on the upper stack and including an insulating material; an upper mold layer on the stopper layer; a cell channel structure extending through the layers, a side surface of the cell channel structure contacting the stopper layer; first and second capping layers; a word line separation structure including a protrusion protruding toward the stopper layer; and a bit line contact plug connected to the cell channel structure, wherein an inner side surface of the stopper layer is offset from an inner side surface of the upper stack, and in contact with the word line separation structure.

Abstract: A semiconductor device includes a stack structure including mold layers and horizontal conductive layers, which are alternately stacked. A channel structure vertically extending in the stack structure is provided. A pillar structure vertically extending in the stack structure is provided. A contact plug connected to a corresponding one of the horizontal conductive layers is disposed. The pillar structure includes a pillar extending through the horizontal conductive layers, and extensions protruding from a side surface of the pillar. Each extension is horizontally aligned with a corresponding one of the horizontal conductive layers.