Semiconductor device including a dielectric layer

A semiconductor device including a dielectric layer is provided. The semiconductor device includes a stack structure, and a vertical structure within the stack structure. The vertical structure includes a lower region having a first width and an upper region having a second width, greater than the first width. The vertical structure further includes two dielectric layers of which respective ratiosof lower thicknesses in the lower region to upper thicknesses in the upper region are different from each other. 提供种包括电介质层的半导体器件。该半导体器件包括堆叠结构和在堆叠结构内的竖直结构。该竖直结构包括具有第宽度的下部区域和具有大于第宽度的第二宽度的上部区域。该竖直结构还包括下部区域中的下部厚度与上部区域中的上部厚度的各自的比值彼此不同的两个电介质层。