The demand for large-format near infrared arrays has grown for both ground-based and space-based applications. These arrays are required for maintaining high resolution over very large fields of view for survey work. We describe results of the development of a new 2048 × 2048 HgCdTe/CdZnTe array with 20-micron pixels that responds with high quantum efficiency over the wavelength range 0.85 to 2.5 microns. With a single-layer anti-reflection coating, the responsive quantum efficiency is greater than 70% from 0.9 micron to 2.4 microns. Dark current is typically less than 4 e-/sec at 80 K. The modular package for this array, dubbed the VIRGO array, allows 3-side butting to form larger mosaic arrays of 4K × 2nK format. The VIRGO ROIC utilizes a PMOS Source Follower per Detector input circuit with a well capacity of about 2 × 105 electrons and with a read noise of less than 20 e- rms with off-chip Correlated Double Sampling. Other features of the VIRGO array include 4 or 16 outputs (programmable), and a frame rate of up to 1.5 Hz in 16-output mode. Power dissipation is about 7 mW at a 1 Hz frame rate. Reset modes include both global reset and reset by row (ripple mode). Reference pixels are built-in to the output data stream. The first major application of the VIRGO array will be for VISTA, the United Kingdom’s Visible and Infrared Survey Telescope for Astronomy. The VISTA focal plane array will operate near 80 K. The cutoff wavelength of the HgCdTe detector can be adjusted for other applications such as SNAP, the Supernova/Acceleration Probe, which requires a shorter detector cutoff wavelength of about 1.7 microns. For applications which require both visible and near infrared response, the detector CdZnTe substrate can be removed after hybridization, allowing the thinned detector to respond to visible wavelengths as short as 0.4 microns.

1K × 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by RVS for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). MIRI provides imaging, coronagraphy, and low and medium resolution spectroscopy over the 5 - 28 μm band. The IBC devices are also suitable for other low-background applications. The Si:As IBC detectors have a pixel dimension of 25 μm and respond to infrared radiation between 5 and 28 μm, covering an important Mid-IR region beyond the 1 - 5 μm range covered by the JWST NIRCam and NIRSpec instruments. Due to high terrestrial backgrounds at the longer Mid-IR wavelengths, it is very difficult to conduct ground-based observations at these wavelengths. Hence, the MIRI instrument on JWST can provide science not obtainable from the ground. We describe results of the development of a new 1024 × 1024 Si:As IBC array that responds with high quantum efficiency over the wavelength range 5 to 28 μm. The previous generation's largest, most sensitive infrared (IR) detectors at these wavelengths were the 256 × 256 / 30 μm pitch Si:As IBC devices built by Raytheon for the SIRTF/IRAC instrument1. Detector performance results will be discussed, including relative spectral response, Responsive Quantum Efficiency (RQE) vs. detector bias, and dark current versus temperature. In addition, Sensor Chip Assembly (SCA) data will be presented from the first Engineering SCAs. The detector ROIC utilizes a PMOS Source Follower per Detector (SFD) input circuit with a well capacity of about 2 × 105 electrons. The read noise of the "bare" MUX is less than 12 e- rms with Fowler-8 sampling at an operating temperature of 7 K. A companion paper by Craig McMurtry (University of Rochester) will discuss the details of SB305 MUX noise measurements2. Other features of the IBC array include 4 video outputs and a separate reference output with a frame rate of 0.36 Hz (2.75 sec frame time). Power dissipation is about 0.5 mW at a 0.36 Hz frame rate. Reset modes include both global reset and reset by row (ripple mode). Reference pixels are built-in to the output data stream. The 1K × 1K IBC is packaged in a robust modular package that consists of a multilayer motherboard, SiC pedestal, and cable assembly with 51-pin MDM connector. All materials of construction were chosen to match the thermal expansion coefficient of Silicon to provide excellent module thermal cycle reliability for cycling between room temperature and 7 K.

We review the various types of astronomy arrays currently available from RIO for wide-field imaging and spectroscopy. Arrays for infrared astronomy became available from RIO (previously the Santa Barbara Research Center) with the introduction of the 58 x 62 InSb in 1984. Since the introduction of this first array, RIO has developed and produced increasingly larger format arrays, including the 256 x 256 InSb array for SIRTF (Space Infrared Telescope Facility) and the Aladdin 1K x 1K array. Over 70 Aladdin arrays have been delivered and are currently deployed on a number of major telescopes throughout the world. RIO is currently developing the next generation of 2K x 2K format arrays. These include the 2K x 2K ORION InSb array, and the VIRGO 2K x K SWIR HgCdTe array for ground-based applications and the 2K x 2K InSb array for the NGST program. In addition, RIO is currently developing the next generation large format 1K x 1K Si:As Impurity Band Conduction (IBC) arrays for the NGST MIR instrument.

Si:As Impurity Band Conduction (IBC) detectors offer many significant advantages over other conventional photon detectors utilized for the infrared. SiAs offer excellent spectral response out to 28 μm with dark current in the 0.01e/second range at 7K over a wide bias range with no tunneling limitations. In addition, because of the perfect thermal match between the Si:As IBC detector and the readout IC (ROIC), hybrids formed by mating Si:As IBCs and ROICs are mechanically stable and have no hybrid reliability problems. Since Si:As IBC detectore are fabricated on readily available Si substrates, large formats are realizable. Si:As IBC detectors have been under development since the mid 80's at Raytheon Vision Systems (RVS). Under the NSAS SIRTF program, a 256 x 256 Si:As array was developed and successfully integrated into the SIRTF IRAC instrument. This same array is also utilized in the ASTRO-F IRC instrument. Both missions will be launched shortly and provide a significant improvement in our ability to measure the spectral signatures of solar type stars and galaxies at high redshifts under very low background conditions in space. Under the NASA Origins program, in collaboration with NASA Ames Research Center (ARC), RVS developed a high performance 1024 x 1024 Si:As IBC array. This array was tested at Ames Research Center. This paper will review the progress of Si:As IBC development at RVS, present test data from ARC, and discuss the more recent developments in Si:As IBC detectors for the JWST MIRI instrument and future missions such as SPICA, TPF, FIRST and DARWIN.

The 1990s saw the rapid evolution of staring IR focal plane arrays (FPAs), with array formats progressing from 128 by 128 arrays at the beginning of the decade, to 1K by 1K arrays in low-rate production at the end of the decade. The maturation of large-format staring FPAs has given astronomers new capabilities for wide-field, high-resolution imaging and spectroscopy. The trends that emerged in the 1990s are continuing with larger format FPAs currently under development.

This paper will describe a 270 X 436 HgCdTe FPA/module that was developed for the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) H and M instruments. Raytheon Infrared Operations was selected by Officine Galileo and the Observatorie de Paris, Meudon to design, fabricate and deliver 4 flight modules for the VIRTIS H and M spectrometers.

This paper will review the state-of-the-art IR detectors at the Raytheon IR Center of Excellence for both grou8nd-based and space-based astronomy applications. Performance data will be presented on 0.5 to 5.0 micron Indium Antimonide (InSb) arrays and 0.9 to 5.0 micron Mercury Cadmium Telluride arrays. In addition, performance data on 2 to 28 micron Arsenic-doped Silicon impurity band conductor arrays will be presented. These very high performance detector array offer another important window into the universe for ground- and space-based astronomical work. Data will include performance data on InSb and Si:As IBC arrays for the IR array camera instrument on NASA's Space IR Telescope Facility and the IRC instrument on the ISAS ASTRO-F IR Imaging Survey (IRIS) mission. Data obtained with the HgCdTe arrays developed for the Visible and IR Thermal Imaging Spectrometer H and M instruments for the ESA ROSETTA mission will also be presented. Readouts for both ground-based and space-based astronomy applications will be highlighted, including the first prototype multiplexer and 4 K X 4 K Focal Plane Array for the next generation space telescope.

This paper is a review of current astronomy projects at Raytheon/SBRC in the near-infrared (IR) band (optical to 5 mu m). Another paper in this same session (3354-11) covers astronomy projects in longer wavelengths. For ground-based astronomy, InSb arrays with formats of 256 x 256, 512 x 512, and 1024 x 1024 have been developed and tested. For space-based astronomy, four projects are discussed with array formats ranging from 256 x 256 to 2K x 2K. The space projects support instruments on the SIRTF, IRIS, NGST, and Rosetta missions. Representative data are presented from 1024 x 1024 and 256 x 256 arrays obtained by test facilities at NOAO and the University of Rochester.