Three-dimensional memory device having adjoined source contact structures and methods for forming the same

Abstract

A plurality of holes are formed extending vertically in a first dielectric deck that includes interleaved a plurality of first sacrificial layers and a plurality of first dielectric layers over a substrate. A plurality of sacrificial structures are formed in the holes. A second dielectric deck is formed having interleaved a plurality of second sacrificial layers and a plurality of second dielectric layers over the first dielectric deck. A slit opening is formed extending in the second dielectric deck, the slit opening aligned with and over the sacrificial source contact structures. The sacrificial structures are removed through the slit openings such that the slit opening is in contact with the holes to form a slit structure. A plurality of conductor layers are formed in the first and second dielectric decks through the slit structure, forming a memory stack. A source contact structure is formed in the slit structure.