Semiconductor devices and data storage systems including the same

A semiconductor device comprising:

• a substrate having a first region, a second region, and a third region;
• gate electrodes stacked on the substrate and spaced apart from each other in the first region and the second region, and the gate electrodes extending in a first direction to have a stepped shape in the third region;
• interlayer insulating layers alternately stacked with the gate electrodes;
• channel structures passing through the gate electrodes in the first region, including a channel layer, and disposed in a first pattern;
• dummy structures passing through the gate electrodes in the second region and disposed in a second pattern, different from the first pattern;
• and
• support structures passing through the gate electrodes in the third region,
• wherein the second region is disposed between the first region and the third region,
• wherein a size of at least a portion of the dummy structures is larger than a size of each of the support structures.

A data storage system comprising:

• a semiconductor device including
• a base substrate,
• circuit devices on the base substrate,
• a substrate disposed on the circuit devices and the substrate having a first region, a second region, and a third region.
• gate electrodes stacked on the substrate and spaced apart from each other in the first region and the second region, and the gate electrodes extending in a first direction to have a stepped shape in the third region,
• interlayer insulating layers alternately stacked with the gate electrodes,
• channel structures passing through the gate electrodes in the first region, the channel structures including a channel layer and disposed in a first pattern,
• dummy structures passing through the gate electrodes in the second region, the dummy structures disposed in a second pattern, different from the first pattern,
• support structures passing through the gate electrodes in the third region, and
• an input/output pad electrically connected to the circuit devices;
• and
• a controller electrically connected to the semiconductor device through the input/output pad and controlling the semiconductor device,
• wherein the second region is disposed between the first region and the third region, and
• wherein a size of at least a portion of the dummy structures is larger than a size of each of the support structures.