Delta-Doped CCDs for Enhanced UV Performance

Thin, backside-illuminated CCds are modified by growing a delta-doped silicon layer on the back surface using molecular beam epitaxy. Delta-doped CCDs exhibit stable and uniform 100 percent internal quantum efficiency. The process consists of growth of an epitaxial silicon layer on a fully-processed commercial CCd die in which 30 percent of a monolayer of boron atoms are incorporated into the lattice nominally in a single atomic layer. Long term stability was tested and showed no degradation of the device quantum efficiency over sixteen months.