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

Abstract

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-μm CMOS image sensor was irradiated with 12 MeV protons at fluences ranging from ${1\times 10}^{11}$ cm⁻² to ${2\times 10}^{12}$ 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.