Structure of two-bit mask read-only memory device and fabricating method thereof

Abstract

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.