Semiconductor devices and data storage systems including the same

Abstract

A semiconductor device includes a lower structure; a pattern structure including first to third pattern layers sequentially stacked on the lower structure; gate electrodes stacked on the pattern structure and spaced apart from each other in a first direction that is perpendicular to an upper surface of the pattern structure, and a channel structure passing through the gate electrodes. The channel structure includes a channel layer and a metal-semiconductor compound layer. The metal-semiconductor compound layer contacts the channel layer and the second pattern layer. The channel structure passes through the second and third pattern layers and extends into the first pattern layer. The second pattern layer has a first metal layer contacting the metal-semiconductor compound layer. At least a portion of the metal-semiconductor compound layer overlaps the lower gate electrode in a second direction perpendicular to the first direction.