A semiconductor device includes a stacked structure including a plurality of gate lines and a plurality of insulation patterns that are alternately stacked in a vertical direction, where the stacked structure defines a vertical hole that extends into the stacked structure and in the vertical direction, a channel film that extends into a vertical hole, and a multiple dielectric layer structure between the channel film and the stacked structure, where the multiple dielectric layer structure includes a plurality of interlayer dielectric layers and a plurality of ferroelectric layers that are alternately stacked and extend from the channel film toward the stacked structure, and where an inner ferroelectric layer of the plurality of ferroelectric layers is thicker than an outer ferroelectric layer of the plurality of ferroelectric layers.