Three-dimensional memory and method for preparing three-dimensional memory

The invention provides a three-dimensional memory and a method for preparing the three-dimensional memory. The method comprises the steps of forming a stacked structure formed by alternately stacking insulating layers and sacrificial layers on a substrate; forming a channel hole penetrating through the stacked structure, wherein the channel hole extends into the substrate to form a bottom groove, and a defect layer exists on the inner surface of the bottom groove; irradiating the inner surface of the bottom groove by using laser under the atmosphere of reducing gas so as to enable the defect layer in the bottom groove to be melted and recrystallized; and performing epitaxial growth on the recrystallized layer within the bottom channel to form an epitaxial layer. According to the preparation method, the increase of the key size of the channel hole caused by removing the oxide layer and the defect layer in the traditional process can be avoided; and the laser only acts on an atomic layer with the limited depth, and the substrate is not obviously bent due to heat generated by the laser, so that the contribution of a reducing gas high-temperature annealing process to the curvature of the substrate is reduced. In addition, the process can be simplified, and the cost is remarkably reduced.