Three-dimensional memory device with annular blocking dielectrics and discrete charge storage elements and method of making thereof

Abstract

A memory opening is formed through an alternating stack of sacrificial material layers and electrically conductive layers located over a substrate. Discrete annular dielectric metal oxide structures are formed on sidewalls of the electrically conductive layers around the memory opening. After forming memory stack structures including the annular dielectric metal oxide structures in the memory opening, lateral recesses are formed by removing the sacrificial material layers selective to the electrically conductive layers. Sacrificial material layers in the memory stack structure are etched at levels of the lateral recesses to form discrete annular structures at each level of the electrically conductive layers, each of which includes, from inside to outside, a respective annular charge storage structure, and a respective blocking dielectric comprising an annular dielectric metal oxide structure.