Semiconductor devices and data storage systems including the same

Abstract

A semiconductor device includes a peripheral circuit structure including: a first substrate, circuit devices on the first substrate, a lower wiring structure electrically connected to the circuit devices, a lower insulating layer covering the lower wiring structure, and a diffusion barrier layer on the lower insulating layer; and a memory cell structure including a second substrate including first and second regions on the peripheral circuit structure, gate electrodes stacked and spaced apart from each other in a first direction perpendicular to an upper surface of the second substrate in the first region and extending in a second direction perpendicular to the first direction to form a staircase shape in the second region, and channel structures penetrating the gate electrodes in the first direction and each including a channel layer. The diffusion barrier layer includes a first material layer having a hydrogen permeability lower than a hydrogen permeability of silicon nitride.