Proton irradiation-induced dark current in 4T CMOS active pixel sensor: Experiment and modeling

F Liu and T Wang and H He and ZG Peng and P Li and T Shi and PA Zhou and CH Chen and CH He and H Zang, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 568, 165861 (2025).

DOI: 10.1016/j.nimb.2025.165861

The investigation of displacement damage mechanisms in CMOS image sensors (CISs) is important for enhancing radiation hardness. In this paper, the generation and annealing effects of irradiation induced dark current are investigated through the combined proton irradiation and a multiscale simulation model. A 0.13-mu m CMOS image sensor was irradiated with 12 MeV protons at fluences ranging from 1 x 1011 cm-2 to 2 x 1012 cm-2. Experimental results on dark current distributions highlight the combined effect of ionization damage and displacement damage after proton irradiation. A reduction of approximately 40 % in the mean dark current was observed during the initial three days of room temperature annealing. The kinetic Monte Carlo (KMC) simulation results indicate that the observed changes in dark current after prolonged annealing may be associated with a reduction of divacancies. These results are highly valuable for understanding the key mechanisms of the displacement damage and predicting performance degradation of irradiated CISs.

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