Semiconductor devices and data storage systems including the same

Abstract

A semiconductor device may include a lower interconnection structure electrically connected to circuit devices on a first substrate, a lower bonding structure connected to the lower interconnection structure and an upper bonding structure, an upper interconnection structure connected to the upper bonding structure, a second substrate on the upper interconnection structure, gate electrodes between the upper interconnection structure and the second substrate, channel structures penetrating through the gate electrodes. The gate electrodes may be spaced apart from each other in a vertical direction. The gate electrodes may include first and second gate electrodes. Each of the channel structures may include a channel layer, which may include a first semiconductor material layer adjacent to the first gate electrodes and a second semiconductor material layer adjacent to the second gate electrodes. Each of the first and second semiconductor material layers may have a single crystal structure or a single crystal-like structure.