Semiconductor devices

A semiconductor device, comprising:

• a substrate having first and second regions;
• gate electrodes that are stacked to be spaced apart from each other in a first direction perpendicular to an upper surface of the substrate in the first region, the gate electrodes extending by different lengths in a second direction perpendicular to the first direction in the second region;
• first separation regions arranged in the first and second regions to pass through the gate electrodes, to extend in the second direction, and to be spaced apart from each other in a third direction perpendicular to the first and second directions;
• second separation regions arranged between the first separation regions to pass through the gate electrodes and to extend in the second direction, portions of the second separation regions being spaced apart from each other in the second direction in the second region;
• and
• an insulation region extending in the third direction to separate at least one of the gate electrodes into two portions adjacent to each other in the second direction,
• wherein the second separation regions include:
• second central separation regions arranged in a single form in the first region and arranged to be spaced apart from each other in a straight line in the second region, and
• second auxiliary separation regions arranged in the second region only, the insulation region being between the first separation region and the second central separation region extending from the first region.