A low noise 2×16 Ge:Sb focal-plane array: Paving the way for large format FPAs for far IR astronomy

Farhoomand, Jam; Sisson, David L.; Beeman, J. W.

doi:10.1016/j.infrared.2007.02.001

Cited by 5 publications

(9 citation statements)

References 20 publications

(26 reference statements)

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“…A detailed account of this FPA along with the results of a comprehensive test highlighting its noise performance has been previously reported [19]. Here, we give a brief overview of the array and the test setup.…”

Section: Test Systemmentioning

confidence: 99%

Viability of layered-hybrid architecture for far IR focal-plane arrays

Farhoomand

Sisson

Beeman

2008

Infrared Physics & Technology

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Section: Test Systemmentioning

confidence: 99%

Viability of layered-hybrid architecture for far IR focal-plane arrays

Farhoomand

Sisson

Beeman

2008

Infrared Physics & Technology

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“…However, there are other materials with smaller bandgaps -such as GaAs ( 310 m) [30] and InAs ( 880 m) [29] that could potentially be used for far IR FPAs. Germanium FPAs have provided high sensitivity, wide dynamic range, and, of great importance, electrical compatibility with the established Si CMOS readout technology [13][14][15][16][17][18]25]. …”

Section: 1-detectormentioning

confidence: 99%

“…We have used this material in the past with excellent results [25]. Figure 3 shows the typical spectral response of this detector and Table 1 summarizes its key characteristics.…”

Section: 1-ge:sb Materials and Processingmentioning

confidence: 99%

“…We have already fabricated a 32x32 CTIA cryogenic readout multiplexer [20,21], have developed a novel approach for hybridizing the detector and the readout which circumvents those problems that could compromise detector performance [22,23], and have demonstrated the feasibility of this approach [24,25]. In this paper we present the design of a fully hybridized 32x32 Ge:Sb photoconductor FPA using the SB349 as the readout.…”

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confidence: 99%

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Design of a 1k pixel Ge:Sb focal-plane array for far-IR astronomy

et al. 2008

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Development of large format, far infrared focal-plane arrays has been identified as a pressing need for future astronomical instruments. In particular, array sizes as large as 128x128 with sensitivities equal to or better than 10 -18 W/ Hz are the goals to be achieved within the next fifteen years. As part of our continuing effort to further this technology, we are developing a 32x32 Ge:Sb photoconductor FPA with a CTIA cryogenic readout multiplexer. A new, layered-hybrid architecture is employed to block the readout glow, improve heat dissipation and temperature uniformity across the array, and alleviate the potential problems associated with the large CTE mismatch between the Ge detector and the Si readout. This is the first 1k-pixel photoconductor FPA of its kind and is meant to be a pathfinder for future large format FPAs. Based on the test results of a prototype 2x16 Ge:Sb array of similar design, we expect the sensitivity of this FPA to be as low as 10 -18 W/ Hz. This paper presents the design, characteristics, and the expected performance of this array.Recent studies of technology needs for future NASA astronomical missions have highlighted the serious lack of capability to fabricate large format focal-plane arrays (FPAs) for the scientifically rich but relatively unexplored far IR and submillimeter region (40-1000 m) [1][2][3]. This important technology has not benefited from the latest advances in FPA development for near and mid-IR primarily because of the absence of commercial and defense drivers. The need for large format far IR FPAs has further been echoed in the specific assessments of SAFIR (Single Aperture Far Infrared Observatory) [4-6] and its subsequent design concept CALISTO (Cryogenic Aperture Large Infrared Space Telescope Observatory) [7,8]. SAFIR/CALISTO is conceptualized as a 10m cold-aperture far IR/sub-mm observatory requiring FPAs larger than 128x128 with sensitivities better than 10 -19 W/ Hz. In addition, such far IR FPAs will be of critical importance to advanced instrumentation for SOFIA (Stratospheric Observatory for Infrared Astronomy) -due to start its observing flights in 2009 -and SPICA (SPace Infrared Telescope for Cosmology and Astrophysics) -a Japanese 3.5m space telescope covering the 5-200 m wavelength range [9].Given this technology need, we have been making incremental progress in fabricating large format photodetector FPAs with the ultimate goal of developing the capability similar to that which currently exists for shorter wavelength IR arrays. The path to establishing such capability is not straightforward since practically all the principal components of such an FPA need to be developed and, due to significant differences between short and long wavelength photodetector materials, the technology for short wavelength FPAs cannot be extended routinely.Our effort has leveraged the rich heritage of the developmental work in this area, in particular the work of Erick Young et al. which culminated in construction of the Ge:Ga FPAs for Spitzer's MIPS instrument [10][11][12]...

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“…Given our target CDS (Fowler-1) read noise of 100 electrons (for 1 sec integration time) and assuming a nominal detector responsivity of 10 A/W (for Ge:Sb at 107 m, 2.6K, and 200mV/mm bias) [14], we estimate the NEP of the array to be 2.26x10 -18 W/ Hz. With 8 samples up the ramp (approximately equivalent to Fowler-4), the NEP should improve by a factor of 2, to 1.13x10 -18 W/ Hz.…”

Section: 4-expected Performancementioning

confidence: 99%

The first look at SB349, a 32x32 CTIA readout multiplexer for far IR focal-plane arrays

2007

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Development of two-dimensional cryogenic readouts suitable for far infrared and submillimeter detectors is a key step in fabrication of large format far infrared focal-plane arrays. In collaboration with Raytheon Vision Systems, we have designed and fabricated the first 32x32 readout multiplexer, SB349, capable of operating at cryogenic temperatures as low as 1.7K. This readout is a capacitive-transimpedance amplifier multiplexed to eight outputs and is buttable on two sides to form a 64x64 mosaic array. It features eight selectable gain settings, AC coupling (auto zero) for better input uniformity, sample-and-hold circuitry, and provisions to block the readout glow. A special, 2-micron cryo-CMOS process has been adopted to prevent freeze out and ensure low noise and proper operation at deep cryogenic temperatures. An overview of the design and the results of the initial functionality tests on this device are reported in this paper.

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A low noise 2×16 Ge:Sb focal-plane array: Paving the way for large format FPAs for far IR astronomy

Cited by 5 publications

References 20 publications

Viability of layered-hybrid architecture for far IR focal-plane arrays

Viability of layered-hybrid architecture for far IR focal-plane arrays

Design of a 1k pixel Ge:Sb focal-plane array for far-IR astronomy

The first look at SB349, a 32x32 CTIA readout multiplexer for far IR focal-plane arrays

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