Semiconductor device and data storage system including the same

Abstract

A semiconductor device includes a stack structure including a gate stack region and dummy stack region. The gate stack region includes interlayer insulating layers and gate electrodes alternately stacked. The dummy stack region includes dummy insulating layers and dummy horizontal layers alternately stacked. A separation structure penetrates the stack structure. A vertical memory structure penetrates the gate stack region in a first region. A plurality of gate contact structures electrically connect to the gate electrodes in a second region. The gate electrodes include a first gate electrode and a second gate electrode disposed on a level higher than the first gate electrode. Each of the gate contact structures includes a gate contact plug and a first insulating spacer. The gate contact plugs include a first gate contact plug penetrating the second gate electrode and contacting the first gate electrode, and a second gate contact plug contacting the second gate electrode.