Two bit memory structure and method of making the same

A method for fabricating a memory structure, comprising:

• providing a substrate having a pad;
• forming an opening in the pad;
• forming a first spacer on a sidewall of the opening;
• filling the opening with a sacrificial layer which has a surface lower than a surface of the first spacer;
• removing the first spacer and exposing a portion of the substrate;
• partially removing the exposed portion of the substrate to define a first trench and a second trench;
• removing the sacrificial layer to expose a surface of the substrate to function as a channel region;
• forming a first dielectric layer on a surface of the first trench, a surface of the second trench and a surface of the channel region;
• filling the first trench and the second trench with a first conductive layer;
• forming a second dielectric layer on a surface of the first conductive layer and the surface of the channel region;
• filling the opening with a second conductive layer;
• and
• removing the pad.