Provided are a semiconductor device and a method of fabricating the same. The method may include forming an electrode structure including insulating layers and electrode layers alternatingly stacked on a substrate, forming a channel hole to penetrate the electrode structure, forming a data storage layer on a sidewall of the channel hole, and forming a semiconductor pattern on a sidewall of the data storage layer to be electrically connected to the substrate. The electrode layers may be metal-silicide layers, and the insulating layers and the electrode layers may be formed in an in-situ manner using the same deposition system.