US Patent 7184315 NROM flash memory with self-aligned structural charge separation

A nitride read only memory (NROM) cell has a nitride layer that is not located under the center of the transistor. The gate insulator layer, with the nitride layer, is comprised of two sections that each have structurally defined and separated charge trapping regions. A charge is stored on a particular trapping region in response to the direction that the transistor is operated. The two sections of the gate insulator separate outer regions of the polysilicon gate structure from the middle region.