| 摘要 |
PURPOSE:To prevent blooming from being caused even when many electric charges are sent from PN-junction to a shift register, by greatly increasing the quantity of transfer charges of a vertical shift register. CONSTITUTION:As charges flow into the storage area of a shift register, storage starts with the maximum potential point of potential file S1 and the charges, when increasing in number enough to let an electron potential reach VG-VFB (voltage applied effectively to transfer electrode), start interfering with the surface. As charges further flow in, almost all the charges are stored at Si-SiO2 interface 304 and the increase continues until the electron potential reaches V2 at point X3. When electrons furthermore increases, they overflow from point X3 to the next transfer stage. The quantity of charges at the point in time when the electron potential increases up to VG-VFB to cause interference with the surface is represented as qNd(Xj-Xn)S (q: unit charge, ND: donor density, Xj: junction depth, Xn: depth from junction surface to where charge resides) and when the potential reaches V2, the quantity of charges is expressed by the formula (Co: oxide film capacity of storage area). |
