The invention relates to the technical field of
semiconductor manufacturing, and especially relates to a 3D
NAND flash memory structure and a manufacturing method therefor. The method comprises the steps: providing a substrate, and sequentially forming a grid oxidation layer, a source selectron
polycrystalline silicon layer, a plurality of stacked oxidation
dielectric layers and sacrificial
dielectric layers, a drain selectron
polycrystalline silicon layer, and a protection oxidation layer; carrying out
etching and forming a cylindrical trench exposing the substrate; forming a tunneling oxidation layer,
polycrystalline silicon and a polycrystalline
silicon isolation
dielectric layer in the cylindrical trench; carrying out
etching and forming a source trench exposing the substrate, and forming a public source
electrode; carrying out wet
etching, and removing the sacrificial dielectric
layers; sequentially forming an
electron capture layer and a blocking oxidation layer on a side wall of the source trench and an inner wall of the oxidation
dielectric layer; and forming a grid
electrode on the surface of the oxidation
dielectric layer. A selectron prepared through the method does not contain
electron capture layer
silicon nitride, thereby avoiding the
threshold voltage drift and electric leakage of the selectron, and improving the quality of a storage device.