Decrease of Dark Current by Reducing Transfer Transistor Induced Partition Noise With Localized Channel Implantation

The local increase of the threshold voltage of the transfer transistor is proposed to reduce the dark current in a CMOS image sensor. It is suggested that the local increase of the threshold voltage controls the partition noise which contributes to the dark current. The dark current is shown to be reduced considerably by the proposed structure. The proposed method induces little change in the hot carrier reliability as well as in the device performance.