John J. Drab

Performance of the JWST/MIRI Si:As detectors

The Mid-Infrared Instrument (MIRI) is a 5 to 28 micron imager and spectrometer that is slated to fly aboard the JWST in 2013. Each of the flight arrays is a 1024×1024 pixel Si:As impurity band conductor detector array, developed by Raytheon Vision Systems. JPL, in conjunction with the MIRI science team, has selected the three flight arrays along with their spares. We briefly summarize the development of these devices, then describe the measured performance of the flight arrays along with supplemental data from sister flight-like parts.

High performance large infrared and visible astronomy arrays for low background applications: instruments performance data and future developments at Raytheon

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 (SCAs) using various detector materials like Si:PIN, 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 × 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).

1024 x 1024 Si:As IBC detector arrays for mid-IR astronomy

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.

RVS large format arrays for astronomy

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 μm. 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.

Synthesis of water soluble precursors for ferroelectric materials

Abstract Solution deposition processes for the production of thin multi-element metal oxide films continue with great interest and varied success. Solution deposition via either sol-gel or MOD (Metal Organic Decomposition) methods are of interest due to the ability to produce a wide variety of compositional products at low capital investment cost. The sol-gel method generally uses hydrolytically sensitive metal alkoxides as the starting materials. Manipulation of the reagents and different hydrolysis rates for multi-element mixtures are issues. The MOD method utilizes large organic acid metal salts as the starting materials. In general, MOD solutions are more hydrolytically stable than the sol-gel solutions. MOD process challenges include large quantities of carbon to be decomposed during the firing, variable chemistry in synthesis of the starting materials (especially when the starting materials for the MOD precursors are metal alkoxides), and long reaction times for the synthesis. For both the current state of the art sol-gel and MOD precursors, toxic and volatile solvents are employed as the vehicle. This paper will review the chemistry related issues to production of consistent high quality metal oxide films via the MOD process. The solid solution BaxSr(1-x)TiO3 will be used as an example. A new technique to quickly obtain controlled carbon content MOD precursor solutions from available starting materials is described. Several new water stable and water soluble BST precursors are described. Details of the electrical properties of capacitors made from the new water based precursors are shown.

A New Ferroelectric Varactor From Water Based Inorganic Precursors

Abstract : Solution deposition processes for the production of thin multi-element metal oxide films continue with great interest and varied success. Solution deposition via either sol-gel or MOD (Metal Organic Decomposition) methods are of interest due to the ability to produce a wide variety of compositional products at low capital investment cost. The sol-gel method generally uses hydrolytically sensitive metal alkoxides as the starting materials. Manipulation of the reagents and different hydrolysis rates for multi-element mixtures are issues. The MOD method utilizes large organic acid metal salts as the starting materials. In general, MOD solutions are more hydrolytically stable than the sol-gel solutions. MOD process challenges include large quantities of carbon to be decomposed during the firing, shrinkage and stress of the thin films, variable chemistry in synthesis of the starting materials (especially when the starting materials for the MOD precursors are metal alkoxides), and long reaction times for the synthesis. For both the sol-gel and MOD precursors, toxic and volatile organic chemical (VOCs) solvents are employed as the vehicle. This paper will review the chemistry-related issues to production of consistent high-quality metal oxide films via the MOD process. The fabrication of thin Ba(x)Sr(1-x)TiO3 (BST) films is described. A new class of MOD precursor has been implemented using polyether acids as the organic vehicle. These new materials are both water stable and water soluble. High quality BST thin films made from these precursors are described and capacitors made from these films are compared to the aliphatic acid MOD materials. Improved capacitors using lower resistance electrodes and interconnects are described, as well as devices designed specifically for our specific application.

Recent focal plane arrays for astronomy and remote sensing applications at RVS

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 (28μm, 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.

Advanced staring Si PIN visible sensor chip assembly for Bepi-Colombo mission to Mercury

The planet Mercury, by its near proximity to the sun, has always posed a formidable challenge to spacecraft. The Bepi-Colombo mission, coordinated by the European Space Agency, will be a pioneering effort in the investigation of this planet. Raytheon Vision Systems (RVS) has been given the opportunity to develop the radiation hardened, high operability, high SNR, advanced staring focal plane array (FPA) for the spacecraft destined (Fig. 1) to explore the planet Mercury. This mission will launch in 2013 on a journey lasting approximately 6 years. When it arrives at Mercury in August 2019, it will endure temperatures as high as 350°C as well as relatively high radiation environments during its 1 year data collection period from September 2019 until September 2020. To support this challenging goal, RVS has designed and produced a custom visible sensor based on a 2048 x 2048 (2k2) format with a 10 μm unit cell. This sensor will support both the High Resolution Imaging Camera (HRIC) and the Stereo Camera (STC) instruments. This dual purpose sensor was designed to achieve high sensitivity as well as low input noise (<100 e-) for space-based, low light conditions. It also must maintain performance parameters in a total ionizing dose environment up to 70 kRad (Si) as well as immunity to latch-up and singe event upset. This paper will show full sensor chip assembly data highlighting the performance parameters prior to irradiation. Radiation testing performance will be reported by an independent source in a subsequent paper.