US Patent 11871567 Three-dimensional memory devices and fabricating methods thereof

A three-dimensional (3D) memory device is disclosed. The 3D memory device comprises an alternating layer stack on a substrate, and a top selective gate cut structure having a laminated structure embedded in an upper portion of the alternating layer stack and extending along a lateral direction. The laminated structure of the top selective gate cut structure comprises a dielectric filling wall and a dummy channel and a dummy functional layer on both sides of the dielectric filling wall.