INTEGRATED CIRCUIT DEVICES AND ELECTRONIC SYSTEMS INCLUDING THE SAME

Integrated circuit devices may include: a gate stack extending on a substrate in a first direction that may be parallel to a main surface of the substrate, the gate stack including a plurality of gate electrodes overlapping each other in a vertical direction that may be perpendicular to the main surface of the substrate; a channel structure extending through the gate stack and extending in the vertical direction; a word line cut opening extending through the gate stack in the vertical direction and extending in the first direction; and an upper support layer on the gate stack and including a hole overlapping the word line cut opening in the vertical direction. An upper surface of the channel structure is in contact with a lower surface of the upper support layer.