Semiconductor devices and data storage systems including the same

Abstract

A semiconductor device includes a first structure including a substrate, circuit devices, a lower interconnection structure electrically connected to the circuit devices, and a second structure on the first structure. The second structure includes a conductive plate layer; gate electrodes on the conductive plate layer and extending in a first direction; separation regions penetrating through the gate electrodes and extending in the first direction; channel structures penetrating through the gate electrodes and respectively including a channel layer; through-contact plugs spaced apart from the gate electrodes and extending in the vertical direction to be electrically connected to the lower interconnection structure of the first structure; first and second contacts electrically connected to the channel layer and the through-contact plugs, respectively; bitlines electrically connecting at least one of each of the first and second contacts to each other; and dummy contacts connected to the bitlines and spaced apart from the through-contact plugs.