Semiconductor device and data storage systems including a semiconductor device

Abstract

A semiconductor device including a first semiconductor structure overlapping a second semiconductor structure, the second semiconductor structure having first and second regions and including a plate layer; gate electrodes spaced apart from each other in a first direction; channel structures passing through the gate electrodes; gate separation regions extending in a second direction; first and second upper isolation regions dividing an upper gate electrode into first, second and third sub-gate electrodes between adjacent gate separation regions; and contact plugs extending in the first direction, each of the first and second upper isolation regions has a region extending in a third direction, and the first sub-gate electrode has a first pad region having a first width and a second pad region having a second width narrower than the first width in a fourth direction, and the first sub-gate electrode is connected to one of the contact plugs.