Collection efficiency and crosstalk in closely spaced photodiode arrays

Lateral diffusion of carriers in closely spaced photodiode arrays leads to image degradation. The effect is analyzed for backside illuminated arrays in the limiting cases of very small and very large optical absorption lengths. It is concluded that closely spaced two‐dimensional arrays for thermal imaging applications will require the use of semiconductors whose thicknesses are less than the diameters of the photodiodes.