Semiconductor memory device

A semiconductor memory device comprising:

• a substrate including a peripheral circuit;
• an interconnection array disposed on the peripheral circuit;
• a cell stack structure disposed on the interconnection array, the cell stack structure including gate electrodes stacked in a vertical direction to form a cell step structure;
• a dummy stack structure disposed on the interconnection array, the dummy stack structure including sacrificial layers stacked in the vertical direction to form a dummy step structure parallel to the cell step structure;
• and
• a doped semiconductor layer disposed between the cell stack structure and the interconnection array and extending to overlap with the dummy stack structure,
• wherein the interconnection array includes a first lower conductive pattern including a center region overlapping with a slit between the cell step structure and the dummy step structure, a first region extending to overlap with the dummy step structure from the center region, and a second region extending to overlap with the cell step structure from the center region, and
• wherein the slit extends to penetrate the doped semiconductor layer.

A semiconductor memory device comprising:

• a substrate including a peripheral circuit;
• an interconnection array disposed on the peripheral circuit;
• a cell stack structure disposed on the interconnection array, the cell stack structure including gate electrodes stacked in a vertical direction to form a cell step structure;
• a dummy stack structure disposed on the interconnection array, the dummy stack structure including sacrificial layers stacked in the vertical direction to form a dummy step structure parallel to the cell step structure;
• and
• a contact plug penetrating the dummy stack structure,
• wherein the interconnection array includes a first lower conductive pattern including a center region overlapping with a slit between the cell step structure and the dummy step structure, a first region extending to overlap with the dummy step structure from the center region, and a second region extending to overlap with the cell step structure from the center region.