| 摘要 |
PURPOSE:To prevent the reduction of sensitivity by dropping an OFD voltage in an overflow drain area during a light accumulating period in a frame transfer type solid-state image pickup element, and increasing remarkably the rate of the charges allowing the whole charges generated at an open window to flow into a channel region. CONSTITUTION:The OFD voltage in the overflow drain area 8 is dropped from conventional VH to VM. Accordingly, the potential of the area 8 comes remarkably shallow, and the electric field generated by the OFD voltage of the area 8 is weakened. Therefore, the charges shown by the dotted line generated by the open window 10 are remarkably improved in the rate to flow into the channel area 9 set in a potential deeper than that of the overflow drain area 8, and most of the generated charges flow into the channel area 9 as shown by the arrow of the full line. On the other hand, the potential of the overflow drain area 8 is set deeper than that of the channel separation area 3. The reason is that the charges excessively generated by the intensive incident light are absorbed for which the overflow drain region 8 has a role as an essential role.
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