Abstract

Dark current mechanisms in a 4-Transistor CMOS imager pixel with a negative gate bias on a transfer gate have been investigated. The increase of dark current with the negative gate bias has been attributed to the Gate-Induced-Leak (GIL) Trap Assisted Tunneling (TAT) by examining dark current dependency both on negative gate bias and on temperature. The negative gate bias on a transfer gate efficiently reduces Shockley -Read-Hall (SRH) dark current but generates GIL-TAT dark current when large negative gate bias is applied.