Proceedings Article | 4 May 2010
KEYWORDS: Staring arrays, Superlattices, Sensors, Quantum efficiency, Semiconducting wafers, Readout integrated circuits, Mercury cadmium telluride, Infrared detectors, Sensor performance, Long wavelength infrared
The antimonide superlattice infrared detector technology program was established to explore new infrared detector
materials and technology. The ultimate goal is to enhance the infrared sensor system capability and meet challenging
requirements for many applications. Certain applications require large-format focal plane arrays (FPAs) for a wide field
of view. These FPAs must be able to detect infrared signatures at long wavelengths, at low infrared background
radiation, and with minimal spatial cross talk. Other applications require medium-format pixel, co-registered, dual-band
capability with minimal spectral cross talk. Under the technology program, three leading research groups have focused
on device architecture design, high-quality material growth and characterization, detector and detector array processing,
hybridization, testing, and modeling. Tremendous progress has been made in the past few years. This is reflected in
orders-of-magnitude reduction in detector dark-current density and substantial increase in quantum efficiency, as well as
the demonstration of good-quality long-wavelength infrared FPAs.
Many technical challenges must be overcome to realize the theoretical promise of superlattice infrared materials. These
include further reduction in dark current density, growth of optically thick materials for high quantum efficiency, and
elimination of FPA processing-related performance degradation. In addition, challenges in long-term research and
development cost, superlattice material availability, FPA chip assembly availability, and industry sustainability are also
to be met. A new program was established in 2009 with a scope that is different from the existing technology program.
Called Fabrication of Superlattice Infrared FPA (FastFPA), this 4-year program sets its goal to establish U.S. industry
capability of producing high-quality superlattice wafers and fabricating advanced FPAs. It uses horizontal integration
strategy by leveraging existing III-V industry resources and taking advantage of years of valuable experiences amassed
by the HgCdTe FPA industry. By end of the program span, three sets of FPAs will be demonstrated-a small-format
long-wave FPA, a large-format long-wave FPA, and a medium-format dual-band FPA at long-wave and mid-wave
infrared.
