| 摘要 |
PURPOSE:To obtain the titled device from which blooming charges are extracted to a substrate by introducing a P-well structure without adopting a planar overflow drain structure. CONSTITUTION:The first well 2 and the second well 3 of the conductivity type reverse to that of the substrate 1 and different impurity concentrations are provided. The photoelectric conversion part 4 is provided in the first well 1 of a lower concentration, and the charge accumulated part 5 and horizontal transfer part 6 in the second well of a higher concentration, respectively. Then, the blooming charges are extracted to the substrate by impressing a fixed voltage between the substrate and the first well 1 at the time of signal charge accumulation so that the first well becomes depleted. On the other hand, a fixed voltage is impressed between the substrate and the first well during the period of vertical fly-back so that the first well becomes non-depleted. As a result, the aperture rate and the sensitivity can be enhanced, and the remarkable improvement in characteristics such as the elimination of after image and the reduction of noise can be attained. |
