| 摘要 |
PURPOSE:To reduce a malfunction by increasing the area of a low resistance layer without making the area of a pattern larger than conventional ones. CONSTITUTION:N<+> type source regions 241, 242, drain regions 251-254 and a diffusion layer 9a low resistance layer) 26 in high concentration (a P<+> type) are formed to the surface of an element region 23 in a substrate 21 surrounded by a field oxide film 22. The low resistance layer 26 is shaped in parallel with gate electrode 28. Since the low resistance layer 26 at the same potential as the substrate 21 is formed in parallel with the gate electrodes 28, the region of the low resistance layer 26 can be ensured in an area remarkably wider than conventional devices in a ROM region. Accordingly, potential difference with the position of the substrate is reduced, and threshold voltage is stabilized, thus preventing the generation of a malfunction. |
