Proton-induced displacement damage distributions and extremes in silicon microvolumes

This paper presents an analytic approach for determining the pixel-to-pixel distribution of particle-induced damage and damage extremes in microvolumes representative of focal plane array pixel geometries. Comparisons between predicted and measured dark current distributions in a silicon charge injection device (CID) show excellent agreement for 12 and 63 MeV proton-induced damage. The calculated and measured damage extremes are compared using extreme value statistical analysis. The calculations reveal how high energy recoils from proton-induced nuclear reactions strongly influence the pixel-to-pixel variation in damage as well as the damage extremes. This analysis provides a valuable tool for assessing the radiation response of a given imager in a particular environment, and its flexibility enables design-phase evaluation of the radiation response for different pixel geometries and materials in a variety of environments. A comparison between Si and GaAs pixels with equal volumes and equal 12 MeV proton fluences indicates both the average damage and its variance are significantly greater in GaAs