A structure of a 2-bit mask ROM device and a fabrication method thereof are provided.
The memory structure includes a substrate, a gate structure, a 2-bit coding implantation
region, a spacer, a buried drain region, an isolation structure and a word line.
The gate structure is disposed on the substrate, while the coding implantation
region is located in the substrate under the side of the gate structure. Further,
at least one spacer is arranged beside the side of the gate structure and a buried
drain region is disposed in the substrate beside the side of the spacer. Moreover,
the buried drain region and the coding implantation region further comprise a buffer
region in between. Additionally, an insulation structure is arranged on the substrate
that is above the buried drain region, while the word lien is disposed on the gate structure.
