| 摘要 |
PURPOSE:To prevent charge information from being deteriorated by forming a gate region at one side of a shift register on a p type substrate between an n type drain layer and a charge storage electrode along a transfer direction, and attaching the prescribed voltage between the well under the gage region and the drain layer. CONSTITUTION:An n type drain layer 6 of the prescribed width is formed on a p type substrate formed with a shift register in a charge transfer direction at one side of the register, and a positive high voltage is applied. An overflow control gate electrode 7 is formed between the drain layers 6 adjacent to storage electrodes 31, 32 on an n type layer in the transfer electrodes of the respective phases, and maintained at the same voltage as the electrodes 31, 32. A transfer channel 4' is formed even under the electrode 7, and a transfer channel under the electrodes 31, 32 is connected via a p<+> type layer 5. When the voltage well under the electrode 7 is selected to the middle value between the transfer electrodes 31, 32 and 3'1, 3'2, the maximum charge amount under the electrode 31 is determined by the difference DELTAV' of the depth under the electrode 7 and smaller than the maximum transfer amount determined by the difference DELTAV under the electrodes 3'1, 31. Accordingly, the excess amount above the maximum storage amount under the electrodes 31 is exhausted at 6 through under the electrode 7, thereby obtaining a shift register having good performance. |
