Semiconductor device including vertical memory structure and separation structure each including side surface slope changing portion and data storage system including the same

Abstract

A semiconductor device includes a stack structure and an insulation structure that covers the stack structure, a vertical memory structure that penetrates the stack structure, and a separation structure that penetrates the stack structure and has an upper surface located at a higher level than an upper surface of the vertical memory structure. The stack structure includes three gate stack groups stacked in a vertical direction. Each of the three gate stack groups includes gate layers stacked and spaced apart from each other in the vertical direction. At a height level between a lowermost gate layer and an uppermost gate layer, a side surface of the vertical memory structure includes memory side surface slope changing portions, and a side surface of the separation structure includes separation side surface slope changing portions positioned at substantially a same height level as some of the memory side surface slope changing portions.