| 摘要 |
PURPOSE: To provide a ROM cell constitution body which does not depend upon the use of a gate oxide film or field oxide film to program, i.e., write a ROM cell under an 'ON' or 'OFF' condition, and the manufacture of the ROM cell constitution body. CONSTITUTION: A ROM cell 24 which is programmed to 'ON' has N+ source impression parts 26 and 32 isolated from a gate by a specific distance by LDDs 28 and 30 bridging the gap between an N+ source and an N channel. A ROM cell 40 which is programmed to 'OFF', on the other hand, has P+ 56 impressed in the gap so as to completely override the LDDs in the gap. Then P+ prevents the N channel from forming an ohmic connection with the N+ source. |
