| 摘要 |
PURPOSE:To utilize an isolation region as an active element and to use it as a parasitic inversion preventive shield by applying negative voltage from a substrate to a polycrystalline silicon film forming an isolation region. CONSTITUTION:A buried channel type MIS field effect transistor Q1 and a write controlling transistor Q2 are provided on a semiconductor substrate 11. In order to isolate the transistor Q1, a groove 12 is formed, and a conductive polycrystalline silicon film 14 is formed in the groove. The transistor Q2 is formed in reverse conductive type to the transistor Q1. Negative voltage is applied from the substrate 11 to the film 14, thereby setting the back gate voltage of the transistor Q2 to zero, and a channel is formed. With this structure, an active element can be formed by utilizing the isolation region which has been heretofore handled as an inactive region. This can also be performed as a function of a parasitic inversion prevention shield. |
