Delta-doped CCDs as stable, high-sensitivity, high-resolution UV imaging arrays

Delta-doped CCDs have achieved stable quantum efficiency, at the theoretical limit imposed by reflection from the Si surface in the near UV and visible. In this approach, an epitaxial silicon layer is grown on a fully-processed commercial CCD using molecular beam epitaxy. During the silicon growth on the CCD, 30% of a monolayer of boron atoms are deposited nominally within a single atomic layer, resulting in the effective elimination of the backside potential well. These devices are highly uniform and have exhibited long-term stability. To achieve significantly higher total quantum efficiency, antireflection layers can be directly deposited on the device. This was demonstrated in the 250-400 nm region.