Patent ID: 6441409
Filing Date: 2002-08-27
Classification: H01L

Abstract:
A charge transfer device comprising:a first charge transfer device including well regions having low potential energy and barrier regions having high potential energy, which can transfer charges supplied thereto from an external device; a second charge transfer device which can transfer charges supplied therefrom from said external device via said first charge transfer device; and a shift gate between said first and second charge transfer devices, which controls the externally supplied charges to be transferred to said first charge transfer device or said second charge transfer device, wherein said first charge transfer device is a semiconductor region between said external device and said second charge transfer device; and each of said well regions of said first charge transfer device comprises a first region having a first dopant concentration and a second region having a second dopant concentration, said first region forming a tapered section whose first end near said second charge transfer device is broader than a second end of the tapered section near said external device, wherein said first end and said second end of the tapered section are joined by first and second side segments and wherein both the first and second side segments are displaced from respective side portions of the barrier regions, wherein said first region is made of n-type silicon whose n-type dopant concentration is higher than that of said second region of said well regions.