A semiconductor device includes a stack structure having a plurality of interlayer insulation layers and a plurality of gate electrode layers which are alternately stacked on a substrate, a ferroelectric insulation layer and a channel layer sequentially stacked on a sidewall of a trench that penetrates the stack structure, and a capping oxide pattern disposed between the ferroelectric insulation layer and each of the plurality of interlayer insulation layers. The capping oxide pattern and the ferroelectric insulation layer include the same metal oxide material.