The invention discloses a three-dimensional
semiconductor memory device based on
deep hole filling and a preparation method of the three-dimensional
semiconductor memory device. The preparation method is suitable for preparing a U-shaped channel of the three-dimensional
semiconductor memory device. The double-
ion-beam deposition technology is adopted, a target material is bombarded with one beam of ions, molecules of the target material overflow and are deposited in a
deep hole along a trail, the surface of the
deep hole is bombarded with the other beam of ions, the deposited material can not cover the top of the deep hole, and therefore it is guaranteed that the U-shaped channel of the three-dimensional
semiconductor memory device is completely formed. Electrodes of the three-dimensional
semiconductor memory device with the U-shaped channel are led out from the upper side of the device, so that the
electrode contact area is reduced; meanwhile, an NAND string of the U-shaped three-dimensional
semiconductor memory device can comprise a stacking structure formed by alternately stacking at least one layer of semiconductors and an
insulation layer, the number of devices in the unit area is increased, and therefore the memory density of the three-dimensional semiconductor memory device with the U-shaped channel can be greatly increased.