This paper investigates arrays of HgCdTe photon trapping detectors. Performance of volume reduced single mesas is
compared to volume reduced photon trap detectors. Good agreement with model trends is observed. Photon trap
detectors exhibit improved performance compared to single mesas, with measured noise equivalent temperature
difference (NEDT) of 40 mK and 100 mK at temperatures of 180 K and 200 K, with good operability. Performance as a
function of temperature has also been investigated.
Polarimetry sensor development has been in work for some time to determine the best use of polarimetry to differentiate
between manmade objects and objects made by nature. Both MWIR and LWIR and 2-color staring Focal Plane Arrays
(FPAs) and LWIR scanning FPAs have been built at Raytheon Vision Systems each with exceedingly higher
performance. This paper presents polarimetric performance comparisons between staring 2562 MWIR, 2562 LWIR, 5122
LWIR/LWIR staring FPAs and scanning LWIR FPAs.
LWIR polarimetry has the largest polarimetric signal level and a larger emissive polarimetric signature than MWIR
which makes LWIR less dependent on sun angles. Polished angled glass and metal objects are easily detected using
While single band 9-11 um LWIR polarimetry has advantages adding another band between 3 and 7 um improves the
capability of the sensor for polarization and spectral phenomenology. In addition the 3-7 um band has improved NEDT
over the 9-11 um band due to the shorter detector cutoff reducing the Noise Equivalent Degree of Linear Polarization.
To gain acceptance polarimetric sensors must provide intelligence signatures that are better than existing nonpolarimetric
Infrared sensors. This paper shows analysis indicating the importance of NEDOLP and Extinction ratios.
Raytheon Visions Systems (RVS) is furthering its capability to deliver state-of-the-art high performance large
format HgCdTe focal plane arrays (FPAs) for dual-band long-wavelength infrared (LWIR) detection. Missile
seekers are designed to acquire targets of interest at long ranges and discriminate targets from clutter. The use of
dual-band long wavelength infrared detector technology provides the ability for these seekers to combine these
operations into the same package with enhanced performance. Increasing the format size of dual-band longwavelength
FPAs and tailoring the detector design for specific long-wavelength bands enables seekers to be
designed for increased field-of-view, longer target acquisition ranges, and improved accuracy. This paper will
review in further detail the aspects of detector design, MBE wafer growth, wafer fabrication, and detector
characterization that are contributing to development and demonstration of high performance large format dual-band
LWIR FPAs at RVS.
Raytheon Vision Systems (RVS) has developed and demonstrated the first-ever 1280 x 720 pixel dual-band MW/LWIR
focal plane arrays (FPA) to support 3rd-Generation tactical IR systems under the U.S. Army's Dual-Band FPA
Manufacturing (DBFM) program. The MW/LWIR detector arrays are fabricated from MBE-grown HgCdTe triple-layer
heterojunction (TLHJ) wafers. The RVS dual-band FPA architecture provides highly simultaneous temporal detection in
the MWIR and LWIR bands using time-division multiplexed integration (TDMI) incorporated into the readout integrated
circuit (ROIC). The TDMI ROIC incorporates a high degree of integration and output flexibility, and supports both
dual-band and single-band full-frame operating modes, as well as high-speed LWIR "window" operation at 480 Hz
frame rate. The ROIC is hybridized to a two-color detector array using a single indium interconnect per pixel, which
makes it highly producible for 20 μm unit cells and exploits mature fabrication processes currently used to produce
single-color FPAs. High-quality 1280 x 720 MW/LWIR FPAs have been fabricated and excellent dual-band imagery
produced at 60 Hz frame rate. The 1280 x 720 detector arrays for these FPAs have LWIR cutoff wavelengths ≥10.5 μm
at 78K. These FPAs have demonstrated high-sensitivity at 78K with MW NETD values < 20 mK and LW NETD values
<30 mK with f/3.5 apertures. Pixel operability greater than 99.9% has been achieved in the MW band and greater than
98% in the LW band.
Raytheon Vision Systems (RVS) is developing two-color, large-format infrared FPAs to support the US Army's Third Generation FLIR systems. RVS has produced 640 x 480 two-color FPAs with a 20 micron pixel pitch. Work is also underway to demonstrate a 1280 x 720 two-color FPA in 2005. The FPA architecture has been designed to achieve nearly simultaneous temporal detection of the spectral bands while being producible for pixel dimensions as small as 20 microns. Raytheon's approach employs a readout integrated circuit (ROIC) with Time Division Multiplexed Integration (TDMI). This ROIC is coupled to bias-selectable two-color detector array with a single contact per pixel. The two-color detector arrays are fabricated from MBE-grown HgCdTe triple layer heterojunction (TLHJ) wafers. The single indium bump design is producible for 20 μm unit cells and exploits mature fabrication processes that are in production at RVS for Second Generation FPAs. This combination allows for the high temporal and spatial color registration while providing a low-cost, highly producible and robust manufacturing process. High-quality MWIR/LWIR (M/L) 640 x 480 TDMI FPAs with have been produced and imaged from multiple fabrication lots. These FPAs have LWIR cutoffs ranging to 11 micron at 78K. These 20 micron pixel FPAs have demonstrated excellent sensitivity and pixel operabilities exceeding 99%. NETDs less than 25 mK at f/5 have been demonstrated for both bands operating simultaneously.
Raytheon Vision Systems (RVS) has invented and demonstrated a new class of advanced focal plane arrays. These Advanced FPAs are sometimes called 3<sup>rd</sup> Generation or “Next Generation” FPAs because they have integrated onto the FPA the ability to sense multiple IR spectrums, have improved resolution and performance, and conduct image processing on the FPA ROIC. These next generation of FPAs are allowing more functionality and the detection of a more diverse set of data than previously possible with 2<sup>nd</sup> Gen FPAs. Examples and history of advanced next generation FPAs are reviewed including RVS’s Multispectral, Uncooled, Adaptive Sensors and other advanced sensors.
An important new area of biomedical engineering is the development of neural prosthesis particularly in the area of cochlear and retinal devices. An intraocular retinal prosthesis test device is currently under development at NRL/JHU. The microelectronic device has an image format of 80 x 40 unit cells interfaced to the retinal surface via an array of microwires in a glass matrix. The system architecture and technology development issues are discussed as well as the topic of biocompatibility. This test device will enable acute human experiments in an operating room environment to demonstrate a massively parallel interface between retinal tissue and a microelectronic array.
Raytheon's Infrared Operations (RIO) has invented and developed a new class of focal plane arrays; the Adaptive IR Sensor (AIRS) and Thinfilm Analog Image Processor (TAIP). The AIRS FPA is based upon biologically inspired on-focal- plane circuitry, which adaptively removes detector and optic temperature drift and l/f induced fixed pattern noise. This third-generation multimode IRFPA, also called a Smart FPA, is a 256x256-array format capable of operation in four modes: 1) Direct Injection (DI), 2) Adaptive Non-uniformity Correction (NUC), 3) Motion/Edge Detection, and 4) Subframe Averaging. Also the 320x240 TAIP results have shown excellent image processing in the form of Spatial and Temporal processing.