| 摘要 |
PURPOSE:To improve the manufacturing yield and the performance by a method wherein the threshold voltage which a transfer gate has is risen up to a required value by reducing the channel width of the transfer gate to less than a specific value. CONSTITUTION:In Figs. (a) and (b), the numeral 7' represents the transfer gate, 2-1 an electrode constituting a vertical CCD, and a thick one-point chain line 20 the channel region of the vertical CCD2, the transfer gate region 7'-1, and a photo diode region 1'. When the channel width (w) constituting the transfer gate 7'-1 exceeds 8mum, the threshold value is constant with little variation. However, the reduction in channel width to less than 8mum shows a gradual increase in threshold voltage, and the reduction to less than 3mum shows a rapid increase. Therefore, when the channel width of the transfer gate is reduced more than a value close to 3mum, the threshold voltage rises by the narrow channel effect: it becomes possible to obtain a necessary threshold voltage not by ion implantation as conventional. |
