Three-dimensional memory devices having isolation structure for source select gate line and methods for forming the same

Abstract

Embodiments of three-dimensional (3D) memory devices and methods for forming the same are disclosed. In an example, a 3D memory device includes a substrate, a memory stack on the substrate, a plurality of channel structures each extending vertically through the memory stack, and one or more isolation structures. The memory stack includes a plurality of interleaved conductive layers and dielectric layers. An outmost one of the conductive layers toward the substrate is a source select gate line (SSG). Each isolation structure surrounds at least one of the channel structures in a plan view to separate the SSG and the at least one channel structure.