With the next generation observatories such as GMT, TMT, and E-ELT looming, the astronomy community is in need of unprecedented number of infrared pixels. To address the affordability of the next generation of infrared instruments, the Center for Detectors (CfD) at the Rochester Institute of Technology (RIT) and Raytheon Vision Systems (RVS) are developing large format, short-wave infrared HgCdTe focal plane arrays grown on silicon (Si) wafers for observational astronomy. The use of silicon wafers offers significant savings and a path to very large format (> 8Kx8K, 15 mu m) focal plane arrays. This paper presents the latest results from the detector development effort and its suitability for use in observational astronomy. Currently, the HgCdTe/Si technology is competitive with the state-of-the-art HgCdTe/CZT technology in many performance metrics, and it has the promise to meet stringent performance requirements posed by observational astronomy. A full suite of characterization results, including for dark current, read noise, spectral response, persistence, linearity, full well, and crosstalk probability, will be presented.

Raytheon Vision Systems (RVS) has a long history of providing state of the art infrared sensor chip assemblies (SCAs) for the astronomical community. This paper will provide an update of RVS capabilities for the community not only for the infrared wavelengths but also in the visible wavelengths as well. Large format infrared detector arrays are now available that meet the demanding requirements of the low background scientific community across the wavelength spectrum. These detector arrays have formats from 1k x 1k to as large as 8k x 8k with pixel sizes ranging from 8 to 27 mu m. Focal plane arrays have been demonstrated with a variety of detector materials: SiPiN, HgCdTe, InSb, and Si: As IBC. All of these detector materials have demonstrated low noise and dark current, high quantum efficiency, and excellent uniformity. All can meet the high performance requirements for low-background within the limits of their respective spectral and operating temperature ranges.

Raytheon Vision Systems (RVS) has been developing high performance low background VisSWIR focal plane arrays suitable for the NASA WFIRST mission. These near infrared sensor chip assemblies (SCAs) are manufactured using HgCdTe on CdZnTe substrates with a 10 micron pixel pitch. WFIRST requirements are for a 4k x 4K format 4-side buttable package to populate a large scale 6 x 3 mosaic focal plane array of 18 SCAs. RVS devices will be compatible with the NASA developed FPA 4-side buttable package, and flight interface electronics. Initial development efforts at RVS have focused on a 2k x 2k format 10 micron pixel design based on an existing readout integrated circuit (ROIC) to demonstrate desired detector material performance at a relevant scale. This paper will provide performance results on the RVS efforts. RVS has successfully developed multiple 4k x 4k 10 micron pixel ROICs and we plan to demonstrate readiness to scale our design efforts to the desired 4k x 4k format for WFIRST in 2016.

The Center for Detectors at Rochester Institute of Technology and Raytheon Vision Systems (RVS) are leveraging RVS capabilities to produce large format, short-wave infrared HgCdTe focal plane arrays on silicon (Si) substrate wafers. Molecular beam epitaxial (MBE) grown HgCdTe on Si can reduce detector fabrication costs dramatically, while keeping performance competitive with HgCdTe grown on CdZnTe. Reduction in detector costs will alleviate a dominant expense for observational astrophysics telescopes. This paper presents the characterization of 2.5μm cutoff MBE HgCdTe/Si detectors including pre- and post-thinning performance. Detector characteristics presented include dark current, read noise, spectral response, persistence, linearity, crosstalk probability, and analysis of material defects.

Astronomers have been interested in performing observations in the very long wavelength infrared band (5–28 m) for decades. IR telescopes are useful to detect very cold or distant objects, so they are important for studying star formation regions, cold stars and extragalactic objects, among others. To this purpose, both groundand space-based observatories have to be equipped with specific sensors that can collect infrared radiation. These so-called impurity band conductor (IBC) sensors have a sensitivity adequate to detect light in the desired spectral range (see Figure 1). They use impurities in the semiconductor to convert long-wavelength photons into an electrical current. We have been manufacturing IBC detectors for many decades.1 These arrays, in multiple formats, can be found in numerous space and ground-based instruments. For example, NASA’s Spitzer Space Telescope’s Infrared Array Camera, for example, uses two IBC detectors and two InSb (Indium antimonide) detectors. Observers used this early instrument for a wide range of astronomical research programs and produced images such as those in Figure 2. The success of Spitzer encouraged the use of large format (wider field of view) IBC arrays. With these devices, astronomers benefit from increased sky coverage and improved sensitivity, thereby decreasing observation time. For instance, we recently delivered 1k 1k IBC mid-infrared detectors to the Jet Propulsion Laboratory (JPL) for the Mid-Infrared Instrument. This device is expected to be on board the planned James Webb space telescope (JWST), successor of the famous Hubble telescope. JPL performed qualification testing and characterization of dark current (the excess current present when a detector has no incoming photons) and noise on these detectors, and both should be minimal for higher performance. While the results delivered by these new IBC arrays will have to wait until the launch of the JWST mission (now delayed by several years), tests showed that Figure 1. Spectral sensitivity of impurity band conductor (IBC) focal planes is well suited for space and ground based astronomy (the photon response to infrared light from 5 to 28 m is excellent).

Raytheon Vision Systems (RVS) has developed a family of high performance large format infrared (IR) detector arrays whose detectors are most effective for the detection of long and very long wavelength IR energy. This paper describes the evolution of the present state of the art one mega-pixel Si: As Impurity Band Conduction (IBC) arrays toward a four mega-pixel array that is desired by the astronomy community. Raytheon's Aquarius-1k, developed in collaboration with ESO, is a 1024 × 1024 pixel high performance array with a 30 μm pitch that features high quantum efficiency IBC detectors, low noise, low dark current, and on-chip clocking for ease of operation. Since the Aquarius-1k array was designed primarily for ground-based astronomy applications, it incorporates selectable gains and a large well capacity among its other features. Raytheon, in collaboration with JAXA (Japan Aerospace Exploration Agency), is also designing a 2048 × 2048 pixel high performance array with a 25 μm pitch. This 2k × 2k readout circuit will be based on the successful design used for the on the Mid-Infrared Instrument (MIRI) aboard the James Webb Space Telescope (JWST). It will feature high quantum efficiency IBC detectors, low noise, low dark current, and on-chip clocking for ease of operation. This version will also incorporate flight qualified packaging to support space-based astronomy applications. Previous generations of RVS IBC detectors have flown on several platforms, including NASA's Spitzer Space Telescope and Japan's Akari Space Telescope.

Raytheon Vision Systems (RVS) arrays are being deployed world-wide in ground based and space based platforms. RVS has a family of high performance visible through far infrared detector arrays for astronomy and civil space applications. Unique and off-the-shelf product lines are readily available to the community. Large sensor chip assemblies using various detector materials like Si PIN, HgCdTe, InSb, and Si: As IBC, covering a detection range from visible (400nm) to mid-wave infrared (28um, MWIR) have been demonstrated with excellent quantum efficiency, dark current, and uniformity. These focal plane arrays have been designed using state-of-the-art low noise, low power, and radiation hardened readout integrated circuits. Complete with optical filters, opto-mechanical packaging, active thermal cooling with matching thermal straps, and optional electronics, RVS provides complete solutions for a multitude of sensor types and mission objectives. This paper describes the recent developments of focal plane assemblies for upcoming missions and telescope platforms.

Raytheon Vision Systems (RVS) has developed a family of high performance large format infrared detector arrays whose detectors are most effective for the detection of long and very long wavelength infrared energy. This paper describes the state of the art in mega-pixel Si:As Impurity Band Conduction (IBC) arrays and relevant system applications that offers unique off-the-shelf solutions to the astronomy community. Raytheon's Aquarius-1k, developed in collaboration with ESO, is a 1024 × 1024 pixel high performance array with a 30μm pitch that features high quantum efficiency IBC detectors, low noise, low dark current, and on-chip clocking for ease of operation. This large format array was designed for ground-based astronomy applications but lends itself for space based platforms too. The detector has excellent sensitivity out to 27μm wavelength. The readout circuit has several programmable features such as low gain for a well capacity of 11 × 106e-, high gain for a well capacity of 106e- and a programmable number of outputs (16 or 64). Programmable integration time and integration modes, like snapshot, rolling and non-destructive integrations, allow the Aquarius to be used for a wide variety of applications and performance. A very fast full frame rate of 120Hz is achieved with 64 outputs (32 outputs per side) and a programmable centered windowing will accommodate a wide range of readout rates. The multiplexer and packaging design utilizes two alignment edges on the SCA which can be butted on two sides for expansion to 2k × 1k and wider focal planes. Data is shown on several focal plane arrays to demonstrate that very low noise and high quantum efficiency performance has been achieved. This array leverages over thirty years of experience in both ground and space based astronomy sensor applications. The technology has been successfully demonstrated on programs such as NASA's Spitzer Space Telescope and Japan's Akari Space Telescope, and will be used on the Mid-Infrared Instrument (MIRI) aboard the James Webb Space Telescope (JWST).

Raytheon Vision Systems (RVS) has developed a family of high performance large format infrared detector arrays for astronomy and civil space applications. RVS offers unique off-the-shelf solutions to the astronomy community. This paper describes mega-pixel arrays, based on multiple detector materials, developed for astronomy and low-background applications. New focal plane arrays under development at RVS for the astronomy community will also be presented.Large Sensor Chip Assemblies (SCAB) using various detector materials like Si:PINT, HgCdTe, InSb, and Si:As IBC, covering a detection range from visible to large wavelength infrared (LWIR) have been demonstrated with an excellent quantum efficiency and very good uniformity. These focal plane arrays have been assembled using state-of-the-art low noise, low power, readout integrated circuits (ROIC) designed at RVS.Raytheon packaging capabilities address reliability, precision alignment and flatness requirements for both ground-based and space applications. Multiple SCAs can be packaged into even larger focal planes. The VISTA telescope, for example, contains sixteen 2k X 2k infrared focal plane arrays.RVS astronomical arrays are being deployed world-wide in ground-based and space-based applications. A summary of performance data for each of these array types from instruments in operation will be presented (VIRGO Array for large format SWIR, the ORION and VISTA Arrays, NEWFIRM and other solutions for MWIR spectral ranges).

This paper presents the infrared detector performance improvement accomplishments by Raytheon Vision Systems (RVS) and by AVYD Devices Inc (AVYD). The RVS-AVYD collaboration has resulted in the demonstration of very large imaging focal plane arrays with respectable operability and performance which could potentially be useful in a variety of promising new applications to advance performance capability for future near and short wave infrared imaging missions. This detector design concept potentially permits ultra-small pixel large format imaging capabilities for diffraction limited resolution down to 5μm pitch focal planes. In this paper, we report on the work performed at the RVS's advanced prototype engineering facility, to fabricate planar detector array wafers with a combination of RVS's Hg1-xCdxTe production material growth and detector fabrication processes and AVYD's p-type ion-implantation process. This paper will review the performance of a 20μm pitch 1,024 x 1,024 format SWIR focal plane array. The detector array was fabricated in Hg1-xCdxTe material responsive from near-infrared to 2.5μm cutoff wavelength. Imaging capability was achieved via interconnect bump bond connection of this detector array to an RVS astronomy grade readout chip. These focal plane arrays have exhibited outstanding quantum efficiency uniformity and magnitude over the entire spectral range and in addition, have also exhibited very low leakage current with median values of 0.25 electrons per second. Detector arrays were processed in engineering grade Hg1-xCdxTe epitaxial layers grown with a modified liquid phase epitaxy process on CdZnTe substrates followed by a combination of passivation/ion implantation/passivation steps. This paper will review the detector performance data in detail including the test structure current-voltage plots, spectral cutoff curves, FPA quantum efficiency, and leakage current.

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.

High performance large infrared detector arrays that meet the demanding requirements of the astronomy and civil space communities are available at Raytheon Vision Systems (RVS). This paper describes multiple detector materials in array formats larger than 1k x 1k developed by RVS for low-background applications. Raytheon features low noise readouts that have been demonstrated with a variety of detector materials: Si PIN, HgCdTe, InSb, and Si:As IBC. All of these detector materials have demonstrated excellent QE uniformity over wavelengths ranging from visible (optical) to 28 mu m. RVS packaging capabilities address reliability, precision alignment and flatness requirements for both ground-based and space applications. Summary performance data of each of these materials on arrays with more than one million detector elements are presented. A look into the future will include "plug and play" mosaic packaging concepts; focal plane electronics; and increasing array formats to 4k x 4k and beyond.

1K x 1K Si:As Impurity Band Conduction (IBC) arrays have been developed by Raytheon Vision Systems for the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). These 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. Detector performance results are discussed, including response and dark current as a function of detector bias and relative spectral response. The features of the matching 1024 x 1024 Readout Integrated Circuit (ROIC) features are discussed. Noise data from the University of Rochester are shown with the ROIC operating at 7 K. Sensor Chip Assembly (SCA) data are presented showing noise, response uniformity, and dark current. Design details of a companion 1024 x 1024 array suitable for high-background, ground-based astronomy will also be revealed for the first time. This array will have a large well capacity and be capable of high frame rates.

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.

Raytheon Vision Systems is under contract to develop 2K x 2K InSb Focal Plane Arrays (FPA) for the ORION and NEWFIRM projects teaming with NOAO, NASA, and USNO. This paper reviews the progress in the ORION, NEWFIRM, and the JWST projects, showing bare mux readout noise at 30 K of 2.4 e- and InSb dark current as low as 0.01 e-/s. Several FPAs have been fabricated to date and the ongoing improvements for the fabrication of FPAs will be discussed. The FPA and packaging designs are complete, resulting in a design that has self-aligning features for ease in FPA replacement at position of the focal plane assembly with alignment accuracy in the focus direction of +/- 12mum. The ORION/NEWFIRM modules are 2-side buttable to easily form 4K x 4K mosaics while the Phoenix modules, developed under the JWST development program, are 3-side buttable for ease in forming 4K x 2NK mosaics where N can be any integer. This paper will include FPA QE, dark current and noise performance, FPA reliability, and module-to-module flatness capabilities.

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.