| 摘要 |
A method of fabricating silicon nitride read only memory. A trapping layer is formed on a substrate. Next, a patterned photoresist layer is formed, and the substrate region at the lower section of the trapping layer masked by the photoresist layer is defined as a channel region. The substrate region at the lower section of the trapping layer and no masked by the photoresist layer is defined as a source/drain region. Next, a pocket ion implantation is performed while using the photoresist layer as amask, and a first dopant is implanted into the source/drain region of the substrate. The photoresist layer is used as a mask and the source/drain ions are implanted. A second dopant is implanted into the source/drain region of the substrate. After that, the photoresist layer is removed. Next, the trapping layer is used as a mask, and a thermal process is performed so that the substrate surface of the source/drain region forms a buried source/drain oxide layer, while at the same time, the second dopant at the lower section of the buried source/drain oxide layer forms a buried source/drain. The first dopant forms the pocket doping region at the edge of the channel region of the buried source/drain periphery as a result of thermal diffusion. Finally, a conductive gate is formed on the substrate.
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