Three-dimensional memory device with discrete self-aligned charge storage elements and method of making thereof

Abstract

A memory opening can be formed through an alternating stack of insulating layers and sacrificial material layers over a substrate. A material layer stack containing, from outside to inside, an aluminum oxide tunneling dielectric layer, a silicon-containing tunneling dielectric layer, and a vertical semiconductor channel is formed within the memory opening. After forming backside recesses by removing the sacrificial material layers, charge trapping material portions are formed on physically exposed surfaces of the aluminum oxide tunneling dielectric layer by employing a selective silicon nitride deposition process. A backside blocking dielectric layer and electrically conductive layers are formed in the backside recesses. The charge trapping material portions are discrete silicon nitride portions located at levels of the electrically conductive layers and vertically spaced from one another by the insulating layers.