PARTICLE-INDUCED SPATIAL DARK CURRENT FLUCTUATIONS IN FOCAL PLANE ARRAYS

Particle-induced degradation of many current imagers is dominated by displacement damage which results in charge transfer inefficiency, increased dark current, and dark current spikes. In this paper, the pixel-to-pixel variation in the radiation-induced dark current increases of a Si focal plane array is calculated analytically using microdosimetry theory. The application of microdosimetry to displacement damage, first introduced in [1], is extended in this paper to include the effects of the electric field distribution on the dark current variance. A test of this calculation is provided through comparisons of the neutron response for two versions of a Si charge injection device (CID), differing primarily in the electric fields present. The most important contributions to the dark current variance are shown to be the variations in the number of primary interactions, the energies of the recoils produced, and the enhanced charge emission from particle-induced defects in high electric field regions. Microdosimetry theory provides a general approach for calculating the dark current variance for any incident particle for which the moments of the recoil spectrum are known, and is shown to successfully predict the dark current response for neutrons and protons. © 1990 IEEE