In a memory device and a method of manufacturing the memory device, a pair of channel layers included in the memory device may be formed on a sidewall of the sacrificial single crystalline layer pattern located on a protrusion of a semiconductor substrate. Accordingly, an etch damage may be reduced at the channel layer. The sacrificial single crystalline layer pattern may be removed to generate a void between the pair of the channel layers. As a result, a generation of a coupling effect may be reduced between the channel layers.