Metal-ono-vacuum tube charge trap flash (VTCTF) nonvolatile memory and the method for making the same

A method of forming a vacuum tube nonvolatile memory, comprising the steps of:

• providing a substrate;
• sequentially forming a dielectric layer, a source layer, a second dielectric layer, a gate layer and a hard mask layer on said substrate;
• patterning said second dielectric layer, said gate layer and said hard mask layer to form a gate structure;
• trimming said second dielectric layer, said gate layer of said gate structure to make the width of said second dielectric layer and said gate layer smaller than the width of said hard mask layer;
• forming a gate dielectric layer on said substrate, and performing etching to form gate dielectric layer sidewalls;
• forming a drain layer;
• and
• forming an interlayer dielectric layer and performing planarization to form a vacuum channel.