InAs/GaSb-based type-II superlattice photodiodes have considerably gained interest as high-performance infrared
detectors. Beside the excellent properties of InAs/GaSb superlattices, like the relatively high effective electron mass
suppressing tunneling currents, the low Auger recombination rate, and a high quantum efficiency, the bandgap can be
widely adjusted within the infrared spectral range from 3 - 30 μm depending on the layer thickness rather than on
composition. Superlattice growth and process technology have shown tremendous progress during the last years. Fully
integrated superlattice cameras have been demonstrated by several groups worldwide.
Within very few years, the InAs/GaSb superlattice technology has proven its suitability for high-performance infrared
imaging detector arrays. At Fraunhofer IAF and AIM, the efforts have been focused on developing a mature fabrication
technology for bispectral InAs/GaSb superlattice focal plane arrays for a simultaneous, co-located detection at 3-4 μm
and 4-5 μm in the mid-wavelength infrared atmospheric transmission window. A very low number of pixel outages and
cluster defects is mandatory for dual-color detector arrays. Sources for pixel outages are manifold and might be caused
by dislocations in the substrate, the epitaxial growth process or by imperfections during the focal plane array fabrication
process. Process refinements, intense root cause analysis and specific test methodologies employed at various stages
during the process have proven to be the key for yield enhancements.