Three-dimensional memory device including replacement insulating layers and methods of forming the same

Abstract

A method of forming a memory device includes forming an alternating stack of disposable material layers and silicon nitride layers over a substrate, forming a memory opening through the alternating stack, forming a memory film in the memory opening, forming a vertical semiconductor channel over the memory film in the memory opening, forming a backside trench through the alternating stack, forming laterally-extending cavities by removing the disposable material layers selective to the silicon nitride layers through the backside trench, oxidizing portions of the silicon nitride layers exposed in the laterally-extending cavities to form insulating layers, and replacing remaining portions of the silicon nitride layers with electrically conductive layers.