| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor storage wherein the structure itself of the storage is highly reliable, and the localization of the captured charges of the storage is maintained, even if excessive writing is carried out in the storage, and further, the variation of the threshold voltages of the storages can be suppressed. SOLUTION: The semiconductor storage has an on-conductivity type band- form semiconductor layer 24a so formed as to be interposed between two opposite conductivity type band-form regions 23a, 23b formed in the surface layer of a semiconductor substrate 21; a first floating gate 27a formed via an insulation film 22a in the region ranging from the top surface of the one-side opposite conductivity type region 23a to the side surface of the one side of the semiconductor layer 24a; a second floating gate 27b formed via an insulation film 22b in the region ranging from the top surface of the other-side opposite conductivity type 23b to the side surface of the other side of the semiconductor layer 24a; and a control gate 30a formed via an insulation film 28 on the top surface of the semiconductor layer 24a.
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