| 摘要 |
PURPOSE:To prevent the data of memory cells from being broken down by impact ionization or charge pump by a method wherein the titled device is so constructed that a memory array is located in an independent well region which is completely isolated from the well forming the circuit around the cell array. CONSTITUTION:A P-well 2-2 of the region II where the memory cell is formed is silated from a P-well 2-1 of the region I where the decoder part and the pre- charge part. Thereby, minority carriers 1 generating e.g. in the external circuit part A of the region by impact ionization or charge pump move toward the memory cell region II only in the amount determined by a certain probability, and minority carriers of lone life-time leave out of the P-well 2-1 to the substrate 3. However, minority carriers leaving out of the P-well 2-1 cannot come into the P-well 2-2 of the memory cell region and cannot therefore reach the node B of the memory cell region. Accordingly, these minority carriers do not act on the node B of the memory cell region I. |
