Three-dimensional memory device including self-aligned drain-select-level isolation structures and method of making thereof

Abstract

An alternating stack of insulating layers and spacer material layers is formed over a substrate. A plurality of arrays of memory opening fill structures is formed through the alternating stack. A plurality of dielectric plates is formed, which laterally surrounds a respective array of memory opening fill structures. Self-aligned drain-select-level isolation structures are formed between a respective neighboring pair of arrays of memory opening fill structures through gaps between neighboring pairs of the dielectric plates into a subset of layers within the alternating stack. Drain side select gate electrodes are provided from a divided subset of the spacer material layers.