Investigation of random telegraph signal in CMOS image sensors irradiated by protons.

CMOS image sensors were irradiated by protons of 50 and 70 MeV and the dark current random telegraph signal (RTS) is investigated. After exposure to the protons, the experimental results provide new evidence that confirms the existence of a correlation between radiation-induced hot pixels and RTS pixels. Moreover, the evolutions of the percentage of hot pixels showing RTS behavior at distinct conditions are presented, suggesting the different dependence of two kinds of pixels on operation conditions. The results of the isochronal annealing experiment demonstrate that the defects responsible for RTS behavior are the cluster defects able to enhance thermal generation through Shockley-Read-Hall (SRH) mechanism.