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Doğrunun tek olduğu ve bilim sayesinde kolaylıkla elde edilebildiği bir anlam dünyası içinde Batılılaşma, Osmanlı topraklarında yeni bir aydın kimliği yaratmakla kalmadı aynı zamanda bu kimliğe yaslandı. Söz konusu bu yeni zümre özellikle Mekteb-i Tıbbiye’de aldıkları eğitiminin sonucunda hayat adını verdikleri süreci kimyasal, fiziksel, biyolojik değişmelere yani “maddi” etmenlere bağlamaktaydı. Pozitivist yaklaşım onlara doğrusal bir tarih anlayışı vermiş ve toplumun fiziksel bir nesne gibi incelenebileceği sanısını yaratmıştı. Öte yandan pozitivizm, aydınların toplumu biçimlendirme çabasına meşruiyet de sağlamaktaydı. Bilimin adım adım ilerlediği bir dünyada toplumların da bilim takip etmeleriyle bizzat tarih doğrusal bir hale gelmekteydi. Bunun anlamı bugün ‘geri’ kalmış olan toplumların ancak ‘ileri’ gitmiş olanları taklit ederek, onların geçtiği yoldan ilerlemenin mümkün olan tek gerçekçi yöntem olduğuydu. “Geri” kalmış toplumlar için modern bilimin gereğine uygun bir toplum ve yaşam biçimi modeli oluşturmak ve toplumu biran önce bu kalıp içinde şekillendirmek gereklilik halini almıştı. Bu doğrultuda ortaya çıkan toplumsal mühendislik faaliyeti öncelikle Mekteb-i Tıbbiye de karşılık bulacak ve buradan yetişenler modernleşmenin taşıyıcı haline gelecekti. Bu çalışma Osmanlı aydınlarının “tarihsel kurtarıcılık” rolünü oynama iradesini kendi içinde nasıl, hangi koşullarda ve niçin hissettiğini, “toplumsal dönüştürücülük” rolünü yerine getirirken hangi yöntemleri izlediklerini ve bütün bunların Mekteb-i Tıbbiye’deki müfredat ile olan ilişkisi üzerinden anlamayı amaçlamaktadır. Türkiye’de birçok sosyal meselenin tarihçilerin ve tarih çalışmalarının gündemine girmeden, romanların konusu olduğu gerçeğini de göz önüne alarak, zengin bir içreğe sahip edebi metinlerin artık daha fazla başvurulan bir akademik alana dönüştüğü de unutulmamalıdır. Dolayısıyla Türk modernleşmesinin yarattığı aydın tipini bütün boyutlarıyla anlamak edebi metinlere de başvurmayı zorunlu hale getirmektedir.

Birinci Dünya Savaşı’nın sonunda Paris Konferansı’nda alınan karar gereği 15 Mayıs 1919 günü İzmir şehri, Yunan ordusu tarafından işgal edilir. İşgal sırasında yaşanan kargaşa bir anda Osmanlı ve Batı kamuoyunun gündemine oturur. Sabah saatlerinde rıhtıma çıkan Yunan birlikleri, Saat Kulesi ve Sarıkışla’yı geçip Kemeraltı girişine geldiğinde bir veya bir kaç el silah sesi duyulur. Bunun üzerine Yunan askerleri; kışlaya, hükümet konağına ve alana bağlanan caddelerle, binalara ateş etmeye başlamış, Yunan askerlerinin açtığı ateş sonucunda çok sayıda Müslüman hayatını kaybetmiştir. Yaşananlardan dolayı ilk kurşun veya kurşunların kaynağıyla ilgili tartışmalar resmi raporlara girmiştir. Milli Mücadele yılları dâhil uzun bir dönem Türkiye’de, Kurtuluş Savaşı’nın İzmir’de Yunan askerlerine karşı atılan “ilk kurşunla” başladığı yönünde bir tarihsel anlatıya başvurulmamış, dolayısıyla “ilk kurşunu” kimin attığı ile ilgili de herhangi bir isim 1940’lara kadar da telaffuz edilmemiştir. Özellikle 1960’lardan sonra Hasan Tahsin (Osman Nevres) ismi ile birlikte “ilk kurşun” kavramı da tarih anlatımına eklemlenmiştir. Bu çalışma “ilk kurşunu” kimin nerede attığından ziyade; Hasan Tahsin’in attığını öne süren tarihsel anlatının referansı kabul edilen eserleri ve bu eserlerde sunulan tarihsel kanıtları kritik etmeyi, öte yandan ise Hasan Tahsin ve “ilk kurşun” etrafında dönen tartışmaların tarihsel serüvenine bakmayı hedeflemektedir.

Hasan Tahsin’in “ilk kurşunu” atarak Millî Mücadeleyi başlattığıtezi tarih anlatımına sonradan eklemlenmiştir. Başta Nutuk olmak üzereMillî Mücadele tarihini anlatan birincil el kaynaklarda “Hasan Tahsin”ve “ilk kurşun” anlatısı yer almaz. Bu çalışma Hasan Tahsin’in “ilk kurşunu”atarak Millî Mücadeleyi başlattığı tezine eleştirel bir yaklaşımlayeniden bakmayı amaçlamaktadır. Tarih biliminin araştırma yöntemlerineuygun olarak öncelikle birinci el kaynaklar taranmıştır. NitekimOsmanlı arşivinde zengin bir belge içeriği ile karşılaşılmıştır. Ardındankonuyla ilgili yabancı arşiv belgelerine başvurulmuş ve son olarak dadönemin Türk basınında yer alan haberler değerlendirmeye alınmıştır.Görgü tanıklarının aktardıkları ise geniş bir literatürü kapsadığı içinayrı makale konusu olarak düşünülmüş ve söz konusu çalışmanın dışındabırakılmıştır.

We report on Hg1−xCdxTe mid-wavelength infrared (MWIR) detectors grown by molecular-beam epitaxy (MBE) on CdZnTe substrates. Current-voltage (I-V) characteristics of HgCdTe-MWIR devices and temperature dependence of focal-plane array (FPA) dark current have been investigated and compared with the most recent InSb published data. These MWIR p-on-n Hg1−xCdxTe/CdZnTe heterostructure detectors give outstanding performance, and at 68 K, they are limited by diffusion currents. For temperatures lower than 68 K, in the near small-bias region, another current is dominant. This current has lower sensitivity to temperature and most likely is of tunneling origin. High-performance MWIR devices and arrays were fabricated with median RoA values of 3.96 × 1010 Ω-cm2 at 78 K and 1.27 × 1012 Ω-cm2 at 60 K; the quantum efficiency (QE) without an antireflection (AR) coating was 73% for a cutoff wavelength of 5.3 µm at 78 K. The QE measurement was performed with a narrow pass filter centered at 3.5 µm. Many large-format MWIR 1024 × 1024 FPAs were fabricated and tested as a function of temperature to confirm the ultra-low dark currents observed in individual devices. For these MWIR FPAs, dark current as low as 0.01 e−/pixel/sec at 58 K for 18 × 18 µm pixels was measured. The 1024 × 1024 array operability and AR-coated QE at 78 K were 99.48% and 88.3%, respectively. A comparison of these results with the state-of-the-art InSb-detector data suggests MWIR-HgCdTe devices have significantly higher performance in the 30–120 K temperature range. The InSb detectors are dominated by generation-recombination (G-R) currents in the 60–120 K temperature range because of a defect center in the energy gap, whereas MWIR-HgCdTe detectors do not exhibit G-R-type currents in this temperature range and are limited by diffusion currents.

Two generations of prototypes of a HgCdTe infrared detector array with 1024 × 1024 pixels developed by the Rockwell International Science Center have been tested in the new Quick Infrared Camera (QUIRC) and an upgraded version of KSPEC a cross-dispersed near-infrared spectrograph, on the University of Hawaii 2.2 m telescope. The HAWAII (HgCdTe Astronomical Wide Area Infrared Imager) prototype devices achieved very good performance. The read-noise in correlated double sampling (CDS) is between 10 and 15 e − rms, depending on the conditions of the operations and the way read-noise is computed. The quantum efficiency in H and K is above 50%. The full-well capacity is above 10 5 e − at 0.5 V applied detector bias and is, in our system, limited by the dynamic range of the A/D converter. The residual excess dark-current problem known from NICMOS-3 devices (Hodapp et al., 1992) [PASP, 104, 441] is not fully resolved. However, it appears less serious in our first HAWAII prototype devices. Using KSPEC, operation under low background conditions has been tested. At an operating temperature of 65 K, and using up to 128 samples of multi-sampling, a read-noise of − and a dark current −1 /min has been demonstrated. Tests of fast sub-array reads for wavefront sensing were conducted using QUIRC. For a sub-array frame repeat time of 11 ms, a read-noise of 6 e − has been demonstrated. An engineering-grade second-generation HAWAII device with reliable hybridization is now in routine operation in KSPEC. The first science-grade HAWAII device has now been installed in the QUIRC camera and is in routine operation. Steven Beckwith

Hybrid HgCdTe 256*256 focal plane arrays have been developed to meet the sensitivity, resolution, and field-of-view requirements of high-performance medium-wavelength infrared (MWIR) imaging systems. The detector arrays for these hybrids are fabricated on substrates that reduce or eliminate the thermal expansion mismatch to the silicon readout circuit. The readouts are foundry-processed CMOS switched-FET circuits that have charge capacities greater than 10/sup 7/ electrons and a single video output capable of 20-MHz data rates. The high quantum efficiency, tunable absorption wavelength, and broad operating temperature range of these large HgCdTe staring focal plane arrays give them significant advantages over competing sensors. The mature Producible Alternative to CdTe for Epitaxy-1 (PACE-1) technology, using sapphire detector substrates, has demonstrated 256*256 MWIR arrays with mean laboratory noise equivalent temperature difference (NETD) of 9 mK for a 4.9- mu m cutoff wavelength, 40- mu m pixel size, and 80-K operating temperature. RMS detector response nonuniformities are less than 4%, and pixel yields are greater than 99%. The newly developed PACE-3 process uses silicon for the detector substrate to eliminate completely the thermal mismatch with the silicon readout circuit. It has the potential for similar performance in even larger array sizes. A 640*480 hybrid array is under development. >

We present the performance of the IR detectors developed for the WFC3 project. These are HgCdTe 1K × 1K devices with cutoff wavelength at 1.7µ m and 150K operating temperature. The two selected flight parts, FPA#64 (prime) and FPA#59 (spare) show quantum efficiency higher than 80% at =1.6 µ m and greater than 40% at >1.1 µ m, readout noise of ~25 e - rms with double correlated sampling, and mean dark current of ~0.04 e/s/pix at 150K. We also report the results obtained at NASA GSFC/DCL on these and ot her similar devices in what concerns the QE long-term stability, intra-pixel response, and dark current variation following illumination or reset. 1. INTRODUCTION The Wide Field Camera 3 (WFC3) is the last imager built for the Hubble Space Telescope (HST). It is intended to replace the WFPC2, extending the wide-field imaging capabilities of the HST. It is based on two optical channels covering with diffraction limited performance the entire wavelength range between 2000A and 1.72 µ m (see Kimble et al., 2004 for an updated report on the status and performance of the instrument). Following the cancellation of the next servicing mission to the HST, WFC3 is now consider ed for installation by an unmanned robotic spacecraft. The infrared channel of WFC3 spans between 0.8µ m and 1.72 µ m. The minimum of background emission at the focal plane of the HST falls within this range ( ~1.6 µ m), at the intersection between the zodiacal scattering and the thermal emission of the warm (~300K, Robberto et al. 2000) HST optical assembly. An IR detector with responsivity peaking in this spectral region, i.e. with long wavelength cutoff at ~1.7 µ m, can be operated at relatively high temperatures (~150K) while keeping the dark current at an acceptably low level, due to the relatively large band-gap. Since temperatures ~150K can be achieved and maintained indefinitely by thermoelectric coolers, unlike disposable cryogenic fluids like LN

Wide Field Camera 3 is a fourth generation instrument for the Hubble Space Telescope (HST), to be installed during the next HST Servicing Mission 4. For its infrared channel Rockwell Scientific Company has developed a new type of HgCdTe 1Kx1K detector, called WFC3-1R, with cutoff wavelength at 1.7μm and 150K operating temperature. The WFC3-IR detectors are based on HgCdTe MBE grown on a CdZnTe substrate and use a new type of multiplexer, the Hawaii-1R MUX. Two flight detectors, a prime and a spare, have been recently selected on the basis of the measures performed at NASA Goddard Research Center - Detector Characterization Laboratory. These parts show quantum efficiency higher than 80% at λ=1.6μm and greater than 40% at λ>1.1μm, readout noise of ~25 e- rms with double correlated sampling, and mean dark current of ~0.04 e/s/pix at 150K. We show that the IR channel of WFC3, equipped with one of these flight detectors, beats the instrument requirements in all configurations and promises to have a discovery efficiency significantly higher than NICMOS. In particular, a two-band wide-area, deep survey made with WFC3 exceeds the discovery efficiency of NICMOS before and after the installation of NCS by a factor of 15 and 10, respectively.

Low background applications place the most stringent requirements on detector material, requiring the lowest possible dark currents, highest quantum efficiencies, negligible image persistence (image latency or “ghosts”), high operability, and good uniformity. Rockwell Scientific’s MWIR (λco=5μm) MBE HgCdTe/CdZnTe consistently meets these stringent requirements due to a number of growth techniques unavailable to other MWIR materials. The first part of this paper focuses on the advantages offered by MBE HgCdTe on CdZnTe detectors. The second part focuses on the functional capabilities of our most recent multiplexers, the HAWAII-1RG and HAWAII-2RG. Finally, the paper briefly concludes with a look at the future of SCA control with Rockwell Scientific’s new NGST ASIC for control and digitization of the HAWAII-RG series multiplexers.

This paper discusses the design and testing of the new HAWAII-2 devices. The HAWAII-2 design is largely based on the very successful HAWAII-1 devices developed by Rockwell, but with an extended detector array size of 2048×2048. The device was designed for use in the AEOS spectrograph, a cross-dispersed spectrograph intended to cover a large spectral range in a single exposure, therefore, array size was of paramount importance.

We have developed a three-dimensional (3D) imaging ladar focal plane array (FPA) for military and commercial applications. The FPA provides snap-shot, direct detection, high-resolution range and range-sampled intensity imaging capability on a single chip. The FPA is made of a 64x64 element, 100-μm pixel pitch detector array that is directly bump bonded to a matched CMOS based silicon readout integrated circuit (ROIC) with parallel ladar signal processing at each pixel. A room temperature, SWIR InGaAs detector variant for imaging near 1.5-μm wavelengths and a cooled MWIR HgCdTe detector variant for imaging near 3-μm to 5-μm wavelengths have been fabricated. We have built a prototype SWIR FPA, integrated it to a compact, transportable SWIR flash ladar transceiver, and collected initial range images outdoors. We present the measured performances of the detector, the readout, and the image data collected with the focal plane array.

Rockwell Scientific's 3rd generation FPAs and sensor chip assemblies (SCA) are complete imaging systems-on-chip for IR and visible cameras. They provide 12-bit to 16-bit digital video at very low power consumption in hybrid and monolithic configurations. A 1936 by 1088 i-SoC with 5μm pixel pitch performs stand-alone visible imaging and a related application-specific integrated circuit supports SCAs. The former generates high-definition video at 30 Hz with

The past 2 to 3 years has been a period of explosive growth in technology development for imaging sensors at Rockwell Scientific Co. (RSC). The state of the art has been advanced significantly, resulting in a number of unique advanced imaging sensor products. A few key examples are: 2048 x 2048 sensor chip assemblies (SCA) for ground and space-based applications, 4096 x 4096 mosaic close-butted mosaic FPA assemblies, a very high performance 10 x 1024 hybridized linear SCA for optical network monitoring and other applications, the revolutionary CMOS ProCam-HD imaging system-on-a-chip for high definition television (HDTV), and RSC's near-infrared emission microscope camera for VLSI defect detection/analysis. This paper provides selected updates of these products and thereby provides an overview of the ongoing highly fertile period of technology and product development at Rockwell Scientific. A view into future directions for advanced imaging sensors is also provided.

Continuing advances in CMOS technology including finer lithography, the addition of dense planarized interconnect layers, concomitant improvements in transistor performance, and the availability of design tools that facilitate large- scale circuit integration, are now enabling the development of systems on a chip. While the first such imaging systems- on-a-chip supported detection of radiation at visible wavelengths, recent imaging systems-on-a-chip extend into the infrared. The result is high-performance infrared FPAs with high functionality. We report our progress at Rockwell Science Center in exploiting submicron CMOS to produce such infrared imaging systems-on-a-chip while overcoming accompanying challenges such as lower operating voltage. Our goal is to develop third-generation infrared imagers with compelling performance and functionality advantages that not only provide high sensitivity and resolution, but also facilitate on-demand sensor selection to adeptly match each mission without need for extensive support logistics including extensive cooling and elaborate camera electronics.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Hg:Cd:Te grown by Molecular Beam Epitaxy onto a lattice matched Cd:Zn:Te substrate with Double Layer Planar Heterostructure architecture holds promise of extremely low, near theoretical dark current out to wavelengths beyond 5 micrometers while eliminating the persistent images and reduced short-wave quantum efficiency disadvantages of the liquid phase epitaxial (LPE) material now in widespread astronomical use. We report on the characterization of two Rockwell FPAs consisting of (lambda) c approximately 4.75 micrometers MBE material hybridized to 1K by 1K HAWAII multiplexers within the context of establishing their performance relative to the stringent focal plane goals for the Next Generation Space Telescope (NGST). The effort has concentrated primarily on characterizing total FPA noise at selected temperatures from 30 to 90 K although short wave quantum efficiency and image persistence have also been measured. The test procedures are based on the use of both DC and variance nosie techniques and, at T approximately 60K, have allowed characterization of the total noise as the sum of separate contributions due to dark current, read noise and read charge. The test facility and characterization techniques are described and results, which verify the remarkable potential of this material to exceed the NGST performance goals at temperatures both at, and also significantly higher than, the approximate 30K now anticipated for the NGST NIR focal pane, are presented.

Rockwell Space Center is developing low-noise visible and IR imaging sensors and systems for astronomy, high-end commercial, NASA, and advanced military applications. The first science grade 2048 by 2048 HAWAII-2 focal plane array (FPA) for astronomy was recently demonstrated for the SWIR waveband. Science-grade deliveries to the University of Hawaii's Institute for Astronomy, the European Southern Observatory and the Subaru Telescope, among others, will soon start. MWIR/visible 2048 by 2048 HAWAII-2 arrays are also being developed for the NGST program using our process for removing the CdZnTe substrate from the back-side illuminated HgCdTe FPAs to detect visible radiation in addition to IR. Previously, more than 25 science grade 2.5micrometers 1024 by 1024 HAWAII FPAs were delivered for use in many observatories; these typically exhibit 90 percent with near-100 percent fill factor, and the dark current is negligible with minimum cooling. Our near-term plan to develop 4096 by 4096 visible and IR FPAs will also be discussed.

Silicon-based hybrid CMOS visible focal plane array (FPA) technology is emerging as a strong contender for scientific applications that require broad spectral response with low noise, highly integrated functionality and radiation hardness. CMOS-based FPAs offer many advantages in high speed, low-noise detection and signal processing. As a high performance alternative to advanced CCD imaging arrays, the hybrid design enables independent optimization of the silicon detector array and silicon readout electronics. Multiplexer commonality with the instrument's IR channels is another attractive feature for integrators of sensor sites such as for hyperspectral spectrometers. In this paper, the technical merits of Rockwell's CMOS-based hybrid visible FPAs are described including key detector performance aspects, interface electronics requirements, radiation hardness and concomitant implications for diverse imaging applications. At this time we have developed 640 X 480 and 1024 X 1024 hybrid imagers with approximately equals 100% optical fill factor, high broadband QE spanning ultraviolet (UV) through near infrared (NIR), wide dynamic range, and high pixel operability. Dark current of approximately equals 0.01e-/sec and read noise approximately equals 6e- have been measured on one prototype 1024 X 1024 FPA that uses Hawaii readout integrated circuit (ROIC). Initial radiation data indicate a total ionization dose (TID) tolerance greater than 35 Krad for our standard CMOS process.

Short wavelength, middle wavelength, mid-long wavelength, long wavelength, and very long wavelength focal plane arrays (FPAs) are required for remote sensing applications. Advances in the Molecular Beam Epitaxy (MBE) growth of Mercury Cadmium Telluride (HgCdTe) and detector architectures utilized, have resulted in high performance detectors being fabricated in the 1 micrometers to 16 micrometers spectral range Custom Read Out Integrated Circuits (ROICs) are designed and fabricated to interface the HgCdTe detector arrays. The hybrid focal pane array is made up of the HgCdTe detector array and the CMOS-based ROIC. Hybrid FPAs performance parameters are presented. The HgCdTe detector material is used are grown by MBE on lattice matched CdZnTe substrates. Custom ROICs are fabricated in a commercial CMOS foundry. FPA D* performance values have been obtained for a multitude of spectral ranges and configurations that include; (i) (lambda) c equals 1.8 micrometers , 12 X 256 arrays operating at 295 K with median D* approximately 1.4 X 1012 cm Hz1/2/W, (ii) (lambda) c equals 10.5 micrometers , 256 X 256 arrays operating at 85 K with medina D* equals 3.9 X 1011 cm Hz1/2/W at a background flux (phi) b equals 7.82 X 1015 ph/cm2-2 and (iii) (lambda) c equals 15.8 micrometers at 65K, 128 X 128 array operating at 40K with peak D* of 2.76 X 1011 cm Hz1/2/W at a background flux (phi) b equals 8.0 X 1015 ph/cm2- s. The performance of these FPAs will be presented.

Corrugated quantum well IR photodetector (QWIP) focal plane arrays (FPAs) with cutoff wavelength of 11.2 and 16.2 micrometers were fabricated and tested. Each detector array has 256 X 256 pixel elements, indium bumped to a direct injection readout circuit manufactured by Rockwell Science Center. The rest of the supporting electronics were designed and built in-house to provide biases and clock functions to the FPAs. IR imageries with good aesthetic attributes were obtained from both FPAs. For the 11.2 micrometers FPA, background limited IR performance (BLIP) was obtained at 63 K under F/2 optics, consistent with the test results of a large area detector. This operating temperature is substantially higher than the grating coupled arrays with comparable cutoff wavelengths. On the other hand, the optics of the present camera were not optimized for wavelengths beyond 14 micrometers . As a result, the BLIP temperature for the 16.2 micrometers FPA, observed to be 38 K, was somewhat lower than the expected 42 K from the single detector characterization. Despite the reduced detector volume of a C-QWIP structure, the measured internal quantum efficiency remains to be high, being 20.5 percent and 25.4 percent at 2 V bias for the 11.2 micrometers and the 16.2 micrometers FPA, respectively.

Rockwell is developing the world's largest HgCdTe IR focal plane array (FPA) for astronomy and low background applications. The format of the device is a hybrid 2048 X 2048 with a unit cell size of 18 micrometers X 18 micrometers . SWIR detectors with a spectral response of 0.85 micrometers to 2.5 micrometers have been processed on liquid phase epitaxy (LPE) HgCdTe on sapphire substrates. The MWIR detectors with a spectral response of 0.4 micrometers to 5 micrometers will be processed on molecular beam epitaxy HgCdTe on CdZnTe substrates. The multiplexer has been designed and fabricated at Conexant. Room temperature probing shows that the device is functional with excellent yield. Novel hybrid fabrication techniques will be used to demonstrate the FPA. This HAWAII-2 device is based on the highly successful HAWAII 1024 X 1024 device and the performance will be similar. The ultimate performance expected from the array is: dark currents of 75 percent across the spectral band, and noise levels of 40K for the MWIR band. The status of the 2048 X 2048 detector arrays and FPAs are discussed.

Infrared (IR) remote sensing imaging applications require high-performance Focal Plane Arrays (FPAs) operating in all ranges of the IR spectrum. Short wavelength (SWIR; 1 to 3 micrometer), middle wavelength (MWIR; 3 to 5 micrometer), mid- long wavelength (MLWIR; 6 to 8 micrometer), long wavelength (LWIR; 8 to 14 micrometer), and very long wavelength (VLWIR; greater than 14 micrometer). These diverse spectral bands require high performance detectors and Read Out Integrated Circuits (ROICs) to perform the multi-spectral mission requirements. Significant progress in the design and fabrication of HgCdTe detector arrays and Read Out Integrated Circuits (ROICs) over the past few years has led to the demonstration of high resolution, low noise and large format reliable FPAs. Hybrid FPAs have been measured and their performance parameters are presented. Focal Plane Array D* performance values have been obtained for a multitude of spectral ranges and configurations that include; (1) (lambda) c equals 1.8 micrometer, 12 X 256 arrays operating at 295 K with median D* approximately 1.4 X 1012 cm Hz1/2/W, (2) (lambda) c equals 2.4 micrometer, 12 X 256 arrays operating at 250 K with median D* equals 1.6 X 1012 cm Hz1/2/W, detectors used are grown by MBE on lattice matched CdZnTe, (3) PACE-1 detectors with (lambda) c equals 2.5 micrometer, 1024 X 1024 arrays operating at 115 K with peak D* of 2.3 X 1013 cm Hz1/2/W at a background flux (phi) b equals 1.2 X 1011 ph/cm2- s, (4) MBE HgCdTe on Silicon MWIR detectors have been fabricated and the detector RoA performance for (lambda) co approximately 5.0 micrometer is in the 106 to 107 ohm-cm2 range at 78 K. (5) MBE HgCdTe on CdZnTe detectors, ((lambda) c equals 15.8 micrometer at 65 K), 128 X 128 array operating at 40 K with peak D* of 2.76 X 1011 cm Hz1/2/W at a background flux (phi) b equals 8.0 X 1015 ph/cm2-s. High performance 640 X 480 arrays imaging in the MWIR band have been fabricated on CdZnTe and PACE-1 substrates. The performance of these and additional FPAs will be presented.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Low-noise pixel-based amplification via sub-micron CMOS is enabling advanced focal plane arrays offering ultra-low read noise for infrared astronomy, wave-front sensing, IR spectroscopy, spaceborne sensors and other discriminating uses. Specifically, we report the achievement of less than 30 e- read noise at video frame rates using capacitive transimpedance amplification and less than 1 e- using an enhanced form of gate modulation. We also compare several low- noise IR FPAs at various cutoff wavelengths from 1.1 micrometer to nearly 17 micrometer.

The HAWAII-2 is an IR 2048 2 focal plane array (FPA) that is being developed for next-generation IR astronomy. It will supplant our HAWAII 1024 2 as the largest high- performance imaging array available for IR astronomy. As with our prior IR sensor, the flip-chip hybrid will consist of a low-capacitance HgCdTe detector array mated to a low- noise CMOS silicon multiplexer via indium interconnects. In order to accommodate reasonable telescope optics and fabrication of the large sophisticated readout using world- class submicron CMOS, the FPA has 18 micrometers pixel pitch. We anticipate > 5 percent yield of defect-free multiplexers using 0.8 micrometers CMOS. The HgCdTe detector arrays will be fabricated on large wafers including sapphire and silicon. Though the first FPAs will have 2.5 micrometers cut-off, the readout will be able to support longer wavelengths. Also reported are the latest 1024 X 1024 FPA results with 2.5 micrometers HgCdTe detectors.

Rockwell Science Center has developed a double layer planar heterostructure (DLPH) detector array fabrication process with significant advantages over the PACE-1 process now being used to produce 256 X 256 and 1024 X 1024 FPAs for low background IR astronomy. The DLPH detectors are p- on-n photodiodes fabricated in a double layer of wide and narrow bandgap HgCdTe grown by molecular beam epitaxy on CdZnTe substrates. The double layer structure provides superior surface passivation while the lattice matched CdZnTe substrate reduces the defect density. DLPH FPAs have been fabricated in array sizes up to 640 X 480 and with cutoff wavelengths as long as 15 micrometers . Quantum efficiencies are typically in the 0.5 to 0.8 range. For a 256 X 256 array DLPH detectors with 5.3 micrometers cutoff wavelength at 50K, the median dark current was 0.39 e-/sec at 0.5V reverse bias. For 7 of 17 individual DLPH detector with 10.6 micrometers cutoff at 30K, the dark current was less than 10 4 e-/sec at 20 mV bias. For long cutoff wavelengths, the detector breakdown voltage is too low to permit signal integration directly on the reverse biased detector capacitance. Such detectors require a readout circuit that maintains the detector near zero bias and provides a separate capacitor to store the integrated signal.

We have developed 1024 X 1024 HAWAII (HgCdTe Arrays for Wide-field Astronomical Infrared Imaging) focal plane arrays (FPAs) for use in astronomical applications. These devices have been delivered to various astronomy organizations around the world and have resulted in increased sensitivities and decreased observation times for deep space imaging. The detector material is PACE-I for SWIR and Molecular Beam Epitaxy (MBE) HgCdTe on CdZnTe for MWIR. The 1024 X 1024 multiplexer has a 18.5 micrometer unit cell pitch, source follower per detector (SFD) input, and it was fabricated at or internal commercial CMOS process line with excellent yield. Mean dark currents as low as 0.02 e-/s have been measured at 77 K for 2.5 micrometer devices (1024 X 1024 format, 18.5 micrometer pitch) and 0.39 e-/s for 5.3 micrometer devices at 50 K (256 X 256 format, 40 micrometer pitch). Quantum efficiencies are greater than 50% for both SWIR and MWIR detectors; with AR coatings, these are expected to be above 75%. Noise levels of 3 e- have been measured by multiple sampling techniques for the SWIR and 75 e- for the MWIR. All of these devices are simple to operate and are readily available. We are presently developing 2048 X 2048 FPAs with 18 micrometer unit cell pitch for both SWIR and MWIR applications.

A corrugated quantum well IR photodetector (C-QWIP) focal plane array (FPA) with cutoff at 11.2 micrometers has been fabricated and characterized. The C-QWIP array uses total internal reflection to couple normal incident light into the pixels. The processing steps involve only one chemical etching, one optional reactive ion etching, and one ohmic contact metalization. The detector array has 256 X 256 pixel elements, indium bumped to a direct injection readout circuit. The photocurrent to dark current ratio measured in this FPA, on which the noise equivalent temperature difference depends, is consistent with that of a large area test sample. The array shows good responsivity uniformity of 5.2 percent with no extra leakage resulted from array processing. The estimated noise equivalent temperature difference of this array, excluding the readout noise, is 17 mK at T equals 63 K. The fact that this FPA can be operated at a temperature similar to those of standard QWIP arrays with much shorter wavelengths shows that the C-QWIP structure can greatly increase array performance.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The ability to hybridize various detector arrays in disparate technologies to an assortment of state-of-the-art silicon readouts has enabled direct comparison of key IR detector technologies including photovoltaic (PV) HgCdTe/Al2O3, PV HgCdTe/CdZnTe, PV InGaAs/InP, and the photoconductive (PC) GaAs/AlGaAs quantum well IR photodetector (QWIP). The staring focal plane arrays range in size from 64 X 64 to 1024 X 1024; we compare these IR detector technologies versus operating temperature and background flux via hybrid FPA test at operating temperatures from 32.5 K to room temperature and photon backgrounds from mid-105 to approximately equals 1017 photons/cm2-s. Several state-of-the-art IR FPAs are included: a 1.7 micrometers 128 X 128 InGaAs hybrid FPA with room temperature D of 1.5 X 1013 cm-Hz1/2/W and 195K D of 1.1 X 1015 cm-Hz1/2/W; a 3.2 micrometers 1024 X 1024 FPA for surveillance; a 4.6 micrometers 256 X 256 HgCdTe/Al2O3 FPA for imaging with BLIP NE(Delta) T of 2.8 mK at 95K; and a 9 micrometers 128 X 128 GaAs QWIP with 32.5 K D > 1014 cm-Hz1/2/W at 32.5K and 8 X 1010 cm-Hz1/2W at 62K.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We have developed two high performance 1024 multiplied by 1024 focal plane arrays for astronomy, spectroscopy, surveillance and conventional imaging. Each hybrid consists of a photovoltaic HgCdTe detector array, fabricated on Al 2 O 3 substrate and having photoresponse cutoff wavelength optimized for each specific application, mated to a CMOS silicon readout via indium column interconnects. In addition to updating the performance of our 1024 multiplied by 1024 FPA for astronomy developed in 1994, we introduce a second 1024 multiplied by 1024 having capability for operation at TV-type frame rates. The latter device also has low read noise but at much higher bandwidth by virtue of its capacitive transimpedance amplifier input and pipelined readout architecture. Both devices have been shown capable of consistently achieving background-limited sensitivity at very low infrared backgrounds (less than or equal to 10 9 photons/cm2-sec) by their low read noise, low dark current including negligible MOSFET self-emission, and high quantum efficiency. FPA pixel operability as high as 99.94% with mean peak D* of 10 14 cm-Hz 1/2 /W has been demonstrated. Proprietary hybridization and mounting techniques are being used to insure hybrid reliability after many thermal cycles. The hybrid methodology has been modeled using finite element modeling to understand the limiting mechanisms; very good agreement has been achieved with the measured reliability.

To achieve the DoD objective of low cost high performance infrared focal plane arrays a manufacturing technique is required which is intrinsically flexible with respect to device configuration and cutoff wavelength and easily scaleable with respect to volume requirements. The approach adopted is to fully develop the technology of molecular beam epitaxy (MBE) to a level where detector array wafers with a variety of configurations can be fabricated with first pass success at a reduced cost. As a vapor phase process, MBE lends itself directly to: (1) the inclusion of real-time monitoring and process control, (2) a single or multiple wafer growth mode, (3) nearly instantaneous changes in growth parameters. A team has been assembled to carry out the program. It is composed of four industrial organizations -- Rockwell International, Hughes Aircraft Company, Texas Instruments, and Lockheed-Martin, and a university -- Georgia Tech Research Institute. Since team members are committed suppliers and users of IRFPAs, technology transfer among team members is accomplished in real-time. The technical approach has been focused on optimizing the processes necessary to fabricate p-on-n HgCdTe double layer heterostructure focal plane arrays, reducing process variance, and on documenting flexibility with respect to cutoff wavelength. Two device structures have been investigated and fabricated -- a 480 by 4 and a 128 by 128.

Attainment of high D* at room temperature via gate-modulated detector interfaceL.J. Kozlowski and K. VuralRockwell Science Center1049 Camino Dos RiosThousand Oaks, CA 91360(805)-373-4267FAX: (805) 373-4687W.E. Kleinhans and T. LiuValley Oak Semiconductor3 1255 Cedar Valley Drive Suite 314Westlake Village, CA 91362G.M. Olson and M. CohenSensors Unlimited, Inc.3490 US Route 1Princeton, New Jersey 08540(609) 520-0610FAX: (609) 520-0638ABSTRACTWe report the performance oflnGaAs and HgCdTe FPAs using multiplexing readouts having gate modulated interface to theinfrared detectors. Gate modulation enables extremely high sensitivity via self-adjusting current gain and concomitant hightransimpedance. At operating temperatures where the detector current was dominated by photocurrent, gate modulationcurrent gain is >40,000 and yields input-referred read noise of

The first prototype of a HgCdTe infrared detector array with 1024 X 1024 pixels developed by the Rockwell International Science Center has been tested in a new infrared camera at the UH 2.2 m telescope, the 0.6 m telescope, and the CFHT. At the 2.2 m tests were conducted both at f/31, where images of very high resolution were obtained using tip-tilt correction, and at f/10 for a wide field of view. At the CFHT both wide field imaging (f/8) and adaptive optics work was done. The HAWAII (HgCdTe astronomical wide area infrared imager) prototype device achieved very good performance. In the camera system, a double correlated readnoise of 15 e - rms was achieved. The dark current at 1 V bias could be confirmed to be below 1 e - , even though the device was operated above 77 K. The quantum efficiency is slightly below 50% and shows the wavy pattern characteristic of LPE-grown HgCdTe. The full well capacity is above 10 5 e - at 1 V bias, limited in our system by the dynamic range of the A/D converter. Data reduction is practically identical to what is used for NICMOS3 256 X 256 devices. Combined integration times of more than 1 hour have been used and demonstrate that the HAWAII devices are suitable for very deep imaging. The residual excess dark current problem known from NICMOS3 devices is not fully resolved. However, it appears less serious in our first HAWAII prototype device.

A comparison of photovoltaic HgCdTe/Al2O3, HgCdTe/CdZnTe, InGaAs/InP and photoconductive GaAs/AlGaAs quantum well infrared photodetector detector technologies has been conducted at Rockwell by exploiting the ability to selectively hybridize disparate mosaic detector arrays to an assortment of silicon multiplexers. Hybrid FPA characteristics are reported as functions of operating temperature from 32.5 K to room temperature and at photon backgrounds from approximately equals 106 to mid-1016 photons/cm2-sec. The staring arrays range in size from about sixteen thousand to over a million pixels. Background-limited detectivities significantly exceeding 1014 cm-(root)Hz/W were achieved.

Rockwell Science Center and the University of Hawaii have developed a short wavelength infrared (SWIR) 1024 x 1024 focalplane array (EPA). The continuing project is funded by the U.S. Air Force Phillips Laboratory in connection with their AdvancedElectro Optical System (AEOS) 3.67 m telescope project on Haleakala, Maui. We have achieved our objective of developing a 1024 x 1024 EPA with a cut-off wavelength of 2.5 im. The device is named the HgCdTe Astronomical Wide Area InfraredImager (HAWAII). The first hybrids have been characterized, delivered and first light achieved two days ahead of schedule; performance highlights include successful elimination of the reset anomaly (whose presence limited the noise performance ofprior astronomical 256 x 256 FPAs), total FPA dark current 99%,quantum efficiency > 50%, BLIP-limited sensitivity at Iow-109 photons/cm2-sec background and operating temperatures to 120K, and read noise < 10 e-. Keywords: Infrared, Focal Plane Array, Astronomy, HgCdTe, 1024 x 1024, Low Noise

The University of Hawaii and the Rockwell International Science Center are developing a large format SWIR detector array optimized for low background astronomical imaging and spectroscopic observations. This so called HgCdTe astronomical wide area IR imager (HAWAII) device will be based on the technology developed for the NICMOS project, but will incorporate several modifications of this design to improve the performance.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Rockwell has developed the 256 x 256 NICMOS3 FPA for the Hubble Space Telescope under funding from NASA through the University of Arizona. Since 1989, dozens of science grade devices have been delivered to astronomers throughout the world for ground based infrared observations. These devices have excellent sensitivity at 77K with mean dark currents of 0.1 e-/s, noise of 25 e-, and quantum efficiency of 55–70%. Pixel yields as high as 99.9% have been achieved. Our present plans are to develop a 1024 x 1024 FPA with 2.5 micron cutoff and make it available to astronomers. Such large arrays are made possible by the advances in detector material size (3 in. diameter PACE-I wafers), multiplexer advances (ability to verify the design in detail and availability of advanced foundries), and novel hybridization and reliability approaches.

A high performance 640 X 480 focal plane array has been developed for the 1 - 5 micron band with excellent sensitivity at temperatures below 120 K. The detectors are processed on 2' or 3' diameter PACE-I (producible alternative to CdTe for epitaxy) HgCdTe material. The multiplexer is a direct injection input, switched-FET device with four independent quadrants. The detector is hybridized to the multiplexer through indium columns and is characterized. A mean camera NE(Delta) T (noise equivalent temperature difference) of 13 mK has been achieved for temperatures

Exploiting hybrid focal plane array methodology and a flexible multiplexing readout, 128 X 128 FPAs were made and directly compared using several short wavelength infrared (SWIR) and long wavelength (LWIR) detector technologies. The detector types include two GaAs/AlGaAs quantum well infrared photodetectors (QWIP), 1.7 micrometers InGaAs/InP, and 2.5 micrometers PV HgCdTe. The tests were performed at operating temperatures ranging from 35 K for the LWIR devices to as high as 175 K for the SWIR FPAs. Highlights include the first FPA demonstrations (to the best of our knowledge) of BLIP-limited detectivity (D*) for both LWIR GaAs/AlGaAs QWIP and 1.7 micrometers PV InGaAs/Inp. The 9 micrometers QWIP peak detectivity is near the theoretical background limit at 1.2 X 10 10 photons/cm 2 -s background and 35 K operating temperature. The mean D* of 4.5 X 10 13 Jones at 8.3 micrometers peak wavelength is 75% of BLIP. A maximum peak D* of 5.7 X 10 14 Jones was achieved with the PV InGaAs/InP device at 200 K. This is also believed to be the highest reported FPA-level D* for a staring mosaic array operated at TV-type frame rate and integration time.

Rockwell's short wavelength infrared (SWIR) focal plane arrays (FPA) were originally designed for use in Orbital Replacement Instrument for the Hubble Space Telescope, but the 256 X 256 FPA version subsequently has found a home in many observatories. Developed for the University of Arizona under a NASA-Goddard prime contract to the University, the device is designated NICMOS3 due to its original relationship with the Hubble's Near Infrared Camera Multi-Object Spectrometer. Typical NICMOS3 FPAs have read noise 50% from 0.8 to 2.5 micrometers . These devices are in use all over the world by many researchers for SWIR astronomy. Based on long-term interaction with these scientists and on our own tests, the consensus is that the NICMOS3 is an extremely useful device. We are working to facilitate several paths for the subsequent low risk development of significantly upgraded astronomical FPAs. These include an even higher performance 256 X 256 FPA consisting of an upgraded readout mated to either standard or improved PACE-1 HgCdTe detector arrays, the near-term development of a 512 X 512 FPA via a proposed astronomical research consortium, and the longer term development of a 1024 X 1024 via several possible paths.

The NICMOS3 infrared focal plane array (FPA), which was designed as a Hubble Telescope upgrade device, provides excellent low-noise images in the 1 - 2.5 micrometers (SWIR) band. Both the detector array and the readout multiplexer of this hybrid FPA are optimized for low- noise operation. The NICMOS detector array is fabricated in HgCdTe grown on a sapphire substrate (PACE-I material). The sapphire substrate is very rugged and provides a good thermal contraction match to the silicon multiplexer, producing excellent reliability. The composition of the HgCdTe is adjusted to yield a response cutoff at 2.5 micrometers which limits the detector response to thermal background from the atmosphere and telescope. The quantum efficiency of the detectors is %GRT 50% over the 1 - 2.4 micrometers range. The dark current of the NICMOS detector is < 1 eMIN/s at 77 K, which is unprecedented for an IR detector. The multiplexer is a switched-FET CMOS design with a single source-follower per unit cell. The photocurrent is integrated on each detector diode, and the diode voltage level can be read nondestructively, or reset after each readout. This flexibility in the FPA operation makes it possible to generate images at a 12 Hz data frame rate or to optimize for low-noise exposures of many thousands of seconds. With a readout before and after each reset, off-chip correlated double sampling can be implemented to reduce the read noise to < 30 e-.

A hybrid HgCdTe 640 X 480 infrared (IR) focal plane array (FPA) that meets the sensitivity, resolution, and field-of-view requirements of high-performance medium wavelength infrared (MWIR) imaging systems has been developed. The key technology making this large, high sensitivity device producible is the epitaxial growth of HgCdTe on a CdTe-buffered, sapphire substrate (referred to as PACE, for Producible Alternative to CdTe for Epitaxy; PACE-I refers to sapphire). The device offers TV resolution with excellent sensitivity at temperatures below 120 K. Mean NE(Delta) T as low as 13 mK has been achieved at operating temperatures < 130 K, which is about an order of magnitude better than has been achieved with PtSi 640 X 480 FPAs. In addition, the latter require cooling to

Staring 128 X 128 hybrid HgCdTe FPAs have been demonstrated with very good sensitivity and operability at temperatures compatible with thermoelectric cooling (> 160 K). The FPAs consist of HgCdTe/sapphire (PACE-I; producible alternative to CdTe for epitaxy) detector arrays hybridized to a CMOS readout having a gate modulation input circuit. FPAs with SWIR (2.5 micrometers at 78 K) and MWIR (4.56 micrometers at 180 K) cutoff wavelengths ((lambda) co) were made and evaluated. The SWIR arrays were ZnS passivated; the MWIR arrays were CdTe-passivated. Though the (lambda) co of the MWIR devices was not specifically optimized for terrestrial imaging at TE-cooled temperatures in the preferred 3.4 to 4.1 micrometers band, very good sensitivity was achieved, particularly relative to other technologies at temperatures >= 120 K. Mean laboratory noise equivalent temperature differences (NE(Delta) T) at 120 K, 170 K, and 180 K were 0.0048 K, 0.053 K, and 0.061 K respectively, for the MWIR device. While the NE(Delta) T was measured without a spectral filter, the sensitivity for 3.4 to 4.1 micrometers bandpass extrapolates to camera NE(Delta) T

PACE-I HgCdTe, an industry-leading intrinsic detector technology for developing large, high performance IR focal plane arrays (IRFPAs) in the MWIR (3-5 microns) spectral band, is reviewed. Emphasis is placed on hybrid HgCdTe 256 x 256 IRFPAs and the status of 640 x 480 hybrid HgCdTe FPA.

We have developed a low dark current, low noise 256 x 256 focal plane array (FPA) for a second generation instrument for the Hubble Space Telescope. The instrument is called NICMOS (Near Infrared Camera Multi-Object Spectrometer) and will have seven 256 x 256 FPAs for different scientific purposes. It is being developed by the University of Arizona and its subcontractors. This retrofit will be installed into the 1-1ST in about five years using the Space Shuttle. The final FPA flight units will be fabricated by our Electro-Optics division. This device is presently the world's largest and most sensitive FPA in waveband of 1.0 -2.5 jim. It is already being successfully used by ground based astronomers.

Cost-effective high-performance IR imaging cameras need affordable staring focal plane arrays (FPAs) that can operate effectively at temperatures compatible with inexpensive long-life coolers. We report on staring hybrid 128 x 128 and 256 x 256 Hg1-xCdxTe FPAs that have requisite yield, sensitivity, operability, and reliability at a medium-wavelength IR (MWIR) cutoff wavelength (λc ~4.6 μm at 180 K) and elevated operating temperatures. Mean 256 x 256 FPA noise-equivalent temperature differences (NEΔT) using broadband f/1.7 optics were 4.3, 7.7, and 55 mK at 120, 140, and 180 K, respectively. We extrapolate that camera NEΔT ≤ 0.02 K can be achieved at 190 K using optimized (λc of ~4.4 μm (180 K), a 3.4- to 4.2-μm bandpass filter, and f/1 optics. Because the CMOS multiplexers have a low-power dissipation and need little ancillary circuitry in the dewar, a viable thermoelectrically-cooled FPA technology is thus implied once the λc is optimized for MWIR imaging.

A high-performance 5-μm 640 X 480 HgCdTe/CdTe/Al2O3 infrared focal plane array (FPA) that offers full TV-compatible resolution with excellent sensitivity at temperatures below 120 K has been developed. Mean FPA D* at 95 K and background of 1014 photons/cm2 s is background-limited at ~1 x 1012 cm Hz1/2/W for the typical mean quantum efficiency of 60 to 70%. The key technology making this large, high-sensitivity device producible is the epitaxial growth of HgCdTe on a rugged CdTe-buffered sapphire substrate. Mean camera noise-equivalent temperature difference NEΔT of 13 mK has been achieved at ≤ 120 K operating temperature and 3.4- to 4.2-μm passband; this is about an order of magnitude better than similar currently available cameras, which use PtSi FPAs and require cooling to ≤ 77 K to maintain performance at low scene temperatures.

Short-wavelength (1-2.5-micron) 128x128 focal plane arrays have been fabricated and demonstrated with high pixel yields and dark-current-limited performance. The detector material is HgCdTe grown by LPE on a sapphire substrate which yields high-performance uniform detectors. The detector arrays were characterized at temperatures of 80-150 K; the peak quantum efficiency at 2.4 microns is 80 percent. The multiplexer is a Reticon FET switch with output amplifiers. It is noted that the long-term goal of this project is to develop a 150x1000 mosaicked focal plane for use in the HIRIS instrument on the Earth Observing System.

Short and medium IR wavelength 64 x 64 hybrid focal plane arrays (FPAs) have been developed using sapphire-grown HgCdTe. The short wavelength arrays were developed for a prototype airborne imaging spectrometer, while those of medium wavelength are suitable for tactical missile seekers and strategic surveillance systems. Attention is presently given to results obtained for these FPAs' current-voltage characteristics, as well as for their characterization at different temperatures. The detector arrays were also mated to a multiplexer and characterized under different operating conditions. The unit cell size used is 52 x 52 microns.