| 摘要 |
PURPOSE:To obtain a directly rewritable memory cells by connecting in series a floating gate type nonvolatile memory element and switching MIS transistor element, causing the control gate of memory element to cross the switching element and by forming the gate and data line with difference materials. CONSTITUTION:A thick isolating oxide film 2 is formed on the specified region of a P type Si substrate 1 and an N<+> type region 3 is formed by ion implantation between a pair of oxide films 2. Then, a thin gate oxide film 4 is deposited on the surface between films 2, a through-hole is bored corresponding to the region 3, the SiO2 film 5 which can be tunneled is formed on the region 3. Thereafter, the floating gates 6a and 6b consisting of the polycrystalline Si are provided in both sides of the film 5, while the polycrystalline Si layer 6 is provided between the films 2 not including the region 3, and these are covered with the Si3N4 film 7. Under this condition, the N type impurity ion is implanted and the N<+> type source, drain regions 8 and 8' are formed respectively in the substrate 1 in both sides of the region 3 and in both sides and under the film 6. |
