Three-dimensional memory devices having a backside trench isolation and methods for forming the same

Abstract

Embodiments of 3D memory devices and methods for forming the same are disclosed. In an example, a 3D memory device includes a substrate having a first side and a second side opposite to the first side. The 3D memory device also includes a memory stack including interleaved conductive layers and dielectric layers at the first side of the substrate. The 3D memory device also includes a plurality of channel structures each extending vertically through the memory stack. The 3D memory device also includes a slit structure extending vertically through the memory stack and extending laterally to separate the plurality of channel structures into a plurality of blocks. The 3D memory device further includes a first doped region in the substrate and in contact with the slit structure. The 3D memory device further includes an insulating structure extending vertically from the second side of the substrate to the first doped region. The 3D memory device further includes a plurality of second doped regions in the substrate and separated by the insulating structure.