| 摘要 |
PURPOSE:To establish the memory device possible for write-in and erase in a short time, by providing the control gate in open condition upward via the insulation film on the floating gate. CONSTITUTION:The n<+> layers 11 and 12 are placed on the p type Si substrate 11 and it is implanted in the SiO2 14 to provide the poly Si floating gate 15 and the control electrode 16 further upward. The control electrode is the poly Si layer of the cross section opening upward, and the distance between the part opposing to the electrode 15 and the substrate surface is smaller than that between the part of electrode 16 not opposing to the electrode 15 and the substrate. With this construction, the storage efficiency storing negative charge to the electrode 15 can sufficiently be made high and since the insulation film 14 between the electrode 16 and the substrate 11 is thick, the dose of ultraviolet rays reaching the electrode 15 through the film 14 is increased. Accordingly, the negative charge discharge time can be reduced and the erase of information is faster. |
