Semiconductor memory devices, methods for fabricating the same and electronic systems including the same

A semiconductor memory device comprising:

• a first substrate that includes a cell array region and an extension region arranged in a first direction;
• a mold structure including mold insulation films and gate electrodes alternately stacked on an upper surface of the first substrate;
• a channel structure in the cell array region that penetrates through the mold structure and intersects the gate electrodes;
• a first dam region in the extension region that has a closed loop in a plane parallel to the upper surface of the first substrate and that cuts the mold structure;
• a second dam region in the extension region that is spaced apart from the first dam region in the first direction, that has a closed loop in the plane parallel to the upper surface of the first substrate, and that cuts the mold structure;
• pad insulation films in the first dam region and second dam region that are alternately stacked with the mold insulation films and that include a material different from the mold insulation films;
• a second substrate including an upper surface that faces a lower surface of the first substrate;
• a peripheral circuit element on the upper surface of the second substrate;
• and
• a first through via in the first dam region that penetrates through the first substrate, the mold insulation films, and the pad insulation films, and connects a gate electrode of the gate electrodes with the peripheral circuit element.

A semiconductor memory device comprising:

• a first substrate;
• a mold structure that includes a plurality of alternately stacked mold insulation films and gate electrodes;
• a channel structure that penetrates the mold structure and that intersects the gate electrodes;
• first and second block separation regions that extend in a first direction parallel to an upper surface of the first substrate and that cut the mold structure;
• first and second dam regions between the first and second block separation regions and spaced apart from each other, the first and second dam regions each cutting the mold structure and each having a closed loop when viewed in a plan view;
• pad insulation films in the first dam region and the second dam region, the pad insulation films alternately stacked with the mold insulation films and including a material different from the mold insulation films;
• and
• a through via in the first dam region that penetrates through the first substrate, the mold insulation films, and the pad insulation films,
• wherein the second dam region has a smaller perimeter in the plan view than the first dam region.