Radiation effects in backside-illuminated CMOS image sensors irradiated by high energy neutrons at CSNS-WNS

We present experiments with BSI-CISs (backside-illuminated CMOS image sensors) conducted at the WNS (white neutron source) at CSNS (China spallation neutron source) facility. Radiation effects of BSI-CISs from irradiation of high energy neutrons are investigated. The image sensors are irradiated in unbiased condition as well as in biased regular operation conditions. The dark current, the dark current non-uniformity, the fixed pattern noise, and the temporal noise versus neutron radiation fluence are analyzed. The degradations of the BSI CISs at different biased condition during neutron radiation are compared. The experimental results of the conversion gain show no change before and after radiation even at 2.0 × 1011 n/cm 2. The degradation mechanisms of the neutron radiation sensitive parameters are demonstrated.