Three-dimensional memory device with a silicon carbon nitride interfacial layer in a charge storage layer and methods of making the same

A method of forming a three-dimensional memory device, comprising:

• forming an alternating stack of insulating layers and spacer material layers located over a substrate, wherein the spacer material layers are formed as, or are subsequently replaced with, electrically conductive layers;
• forming memory openings through the alternating stack;
• and
• forming a memory stack structure within each memory opening,
• wherein:
• each memory stack structure comprises a memory film and a vertical semiconductor channel;
• and
• each memory film is formed by:
• forming a silicon nitride layer over a sidewall of a respective memory opening;
• forming a silicon carbon nitride interfacial layer on the silicon nitride layer;
• and
• forming a tunneling dielectric layer on the silicon carbon nitride interfacial layer.