Three-dimensional memory devices

A device comprising:

• a word line having a main portion, a first projecting portion, and a second projecting portion, the first projecting portion and the second projecting portion each extending away from opposite sides of the main portion;
• a first memory layer extending along the first projecting portion and the main portion of the word line;
• a first channel region extending along the first memory layer;
• a second memory layer extending along the second projecting portion and the main portion of the word line;
• and
• a second channel region extending along the second memory layer.

A device comprising:

• a staircase structure comprising:
• a first dielectric layer;
• a second dielectric layer;
• and
• a word line between the first dielectric layer and the second dielectric layer, the word line having an outer sidewall and an inner sidewall, the inner sidewall being recessed from the outer sidewall;
• a memory layer extending along the outer sidewall and the inner sidewall of the word line;
• an isolation region on the memory layer, a top surface of the isolation region being coplanar with a top surface of the memory layer and a top surface of the staircase structure;
• and
• a channel region between the isolation region and the memory layer.