| 摘要 |
PURPOSE:To prevent decrease in saturated amount of charge and dispersion in picture elements in solid state image pickup device, by forming a second impurity region which is adjacent to a first impurity region by self-aligning method utilizing selective etching. CONSTITUTION:On a semiconductor substrate 10, an oxide film 11, a poly Si layer, and a silicon nitride film are provided. Holes are provided in the poly Si layer and the silicon nitride film. Impurities whose conductive type is the same as that of the substrate are implanted through said holes, and the first impurity regions 15a-15d are formed. After the exposed sides of the poly Si layer are oxidized, a poly Si layer 17 is provided on the entire surface. Holes are provided at specified parts, and an oxide film 18 is formed on the sides and the surface. Then the poly Si layer directly below the holes is selectively etched away by utilizing the selective etching, and an insulator including reverse conductive impurities is provided at the removed part. An overflow drain is formed directly below the insulator. Thus the performance of the solid image pickup device is improved. |
