Semiconductor memory devices and their manufacturing methods

Abstract

This invention provides a semiconductor memory device capable of improving the characteristics of memory cells. In a cross-section obtained by cutting a word line WL and a memory cylinder MP along the X and Z directions, the semiconductor memory device has a central portion and an end portion on the Z-direction end face of the word line WL. In the X direction, an insulating layer 53, an insulating layer 52, an insulating layer 51, and a semiconductor layer 50 are sequentially provided on the end face of the word line WL. The first thickness of the insulating layer 53 facing the end portion of the end face of the word line WL is different from the second thickness of the insulating layer 53 facing the central portion of the end face of the word line WL. The insulating layers 52, 51, and 50 facing the end face of the word line WL are arranged in a straight line along the Z direction.

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