US Patent 11991880 Three-dimensional memory devices and fabricating methods thereof

A method for forming a 3D memory device is disclosed. The method includes: forming an alternating dielectric stack on a substrate; forming a plurality of channel holes penetrating the alternating dielectric stack; forming a channel structure in each channel hole; forming a channel column structure on the channel structure in each channel hole; trimming an upper portion of each channel column structure to form a channel plug; and forming a top selective gate cut between neighboring channel plugs.