| 摘要 |
Semiconductor memory device comprises a semiconductor substrate region of a first conductivity type; a memory cell including a switching MOS transistor having a first and a second impurity region of a second conductivity type, a capacitor connected to the transistor for storing memory data, and a third and a fourth impurity region of the first conductivity type. The third impurity region is formed between, and entirely sepg. the substrate region form both the first impurity region and the capacitor, and having a higher impurity concn. than that of the substrate region. the fourth impurity region is formed between, and entirely sepg. the substrate concn. than that of the substrate region. The third and fourth regions enhance radiation immunity of the memory device.
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