Semiconductor memory device having horizontally spaced selection structures and electronic system including the same

Abstract

Disclosed are semiconductor devices and electronic systems including the same. The semiconductor device may include a stack structure extending in a first direction and including gate electrodes vertically stacked on a substrate, selection structures horizontally spaced apart on the stack structure, an upper isolation structure between the selection structure and extending in the first direction on the stack structure, and vertical structures penetrating the stack structure and the selection structures. The vertical structures include first vertical structures arranged along the first direction and penetrating portions of the upper isolation structure. Each selection structure includes a selection gate electrode and a horizontal dielectric pattern that surrounds top, bottom, and sidewall surfaces of the selection gate electrode. Each selection gate electrode includes a line part extending in the first direction, and an electrode part vertically protruding from the line part and surrounding at least a portion of each first vertical structure.