| 摘要 |
PURPOSE:To prevent the vertical fringe of dense and pale density from presenting on a reproduced image by forming a channel forming portion having a narrow channel width by reducing the impurity density of a P type well region to raise a channel potential and forming a channel forming portion having a wide channel width by increasing the impurity density of the P type well region to reduce the channel potential. CONSTITUTION:A thin oxide film 15 is formed on an N type semiconductor substrate 11, and boron ions are implanted to the substrate. Then, a silicon nitride film is formed on the surface, and the silicon nitride film 17 remains only on a channel forming portion by photoetching. A thick oxide film 14 is partly formed on the portion not corresponding to the channel forming portion, the film 17 is removed, heat treated to form P type well regions 121, 122. Then, since the area under the thin oxide film (hole) of the region 121 is larger than that of the region 122, an average impurity density is higher in the region 121. |
