Three-dimensional memory device and method for forming the same

Abstract

Embodiments of a three-dimensional (3D) memory device are provided. A method for forming a 3D memory device is disclosed. A dielectric stack including interleaved sacrificial layers and dielectric layers is formed over a substrate. Channel holes and contact holes are formed through the dielectric stack. The contact holes extend vertically into the substrate and are each surrounded by channel holes of nominally equal lateral distances to the respective contact hole in a plan view. A channel structure is formed in each of the channel holes. A memory stack having interleaved conductive layers and dielectric layers is formed by replacing, through the contact holes, the sacrificial layers in the dielectric stack with the conductive layers. A spacer is formed along a sidewall of each of the contact holes to cover the conductive layers of the memory stack. A contact is formed over the spacer in each of the contact holes. The contact is electrically connected to a common source of the channel structures.