Semiconductor memory device and manufacturing method of semiconductor memory device

Abstract

A dynamic flash memory is formed by stacking, on a first impurity layer on a P-layer substrate, a first insulating layer, a first material layer, a second insulating layer, a second material layer, a third insulating layer, a third material layer, and a fourth material layer, forming a first hole penetrating these layers on the P-layer substrate, forming a semiconductor pillar by embedding the first hole with a semiconductor, removing the first, second, and third material layers to form second, third, and fourth holes, by oxidizing an outermost surface of the semiconductor pillar exposing in the second, third, and fourth holes to form first, second, and third gate insulating layers, and forming first, second, and third gate conductor layers embedded in the second, third, and fourth holes.