Uniting IR detectors for tactical and space applications: a continuous cycle for reliability
Authors: Xavier Breniere, Philippe Tribolet
Published 7 May 2009
Sofradir IR detectors are being deployed in a lengthening line of space applications (earth observation, atmospheric observation, scientific missions, etc.). At first glance, one may ask what do detectors for space applications have in common with detectors for tactical applications? This paper describes how Sofradir is able to take advantage of both space and tactical applications in their development of infrared detectors because the core of the technologies and manufacturing processes common to both applications. The result, is a continuous cycle for reliability of IR detectors, accelerating reliability growth in production and at the same time meeting stringent requirements for space applications.

Fifty years of successful MCT research and production in France
Authors: Philippe Bensussan, Philippe Tribolet, Gérard Destéfanis, et al.
Published 7 May 2009
France has a long and fruitful history regarding Mercury Cadmium Telluride (MCT) research and production and is still one of the leading countries for the production of MCT IR detectors. This paper gives a historical account of its development and progress, describing the early days of MCT developments, as well as research carried out on second- and third-generation MCT technologies, and production of these detector types.

Ultra-low power ADC on chip for high-performance IR detector
Authors: Gilbert Decaens, Michel Zecri, Patrick Maillart, et al.
Published 6 May 2009
The Infrared staring arrays developed by SOFRADIR are more and more compact and offer system solutions for wide range of IR wavebands. IR detectors have been taken to an even more advanced level of sophistication to achieve staring arrays high performances. Latest developments have also been focused on the silicon readout circuit. Digital conversion on chip is one of the recent progresses in this field of activity. In order to match each system requirements, on chip high performance ultra low power ADCs have been developed. Beyond the performance aspects, digital focal plane arrays can be considered as the first step towards low cost Dewar family, since they allow for a simpler electrical interface on Dewar designs and on chip image processing. Recent results concerning these new readout circuit architectures are presented in this paper.

Status of very long infrared-wave focal plane array development at DEFIR
Authors: O. Gravrand, Ph. Chorier
Published 6 May 2009
The very long infrared wavelength (>14μm) is a very challenging range for the design of large HgCdTe focal plane arrays. As the wavelength gets longer (ie the semiconductor gap gets smaller), the physic of photodiodes asks for numerous technological improvements to keep a high level of detection performance. DEFIR (LETI-Sofradir common research team) has been highly active in this field during the last few years. The need for very long wave focal plane arrays appears very demanding in terms of dark current, defect density and of course quantum efficiency. This paper aims at presenting a status of long and very long wave focal plane array development at DEFIR for three different ion implanted technologies: n on p mercury vacancies doped technology, n on p extrinsic doped technology, and p on n arsenic on indium technology. Special focus is done to 15μm cut off n/p focal plane array fabricated in our laboratory demonstrating high uniformity, diffusion and shot noise limited photodiodes at 50K.

New high-gain detectors for active imaging
Authors: Frederic Pistone, P. Tribolet, X. Lefoul, et al.
Published 6 May 2009
New applications require high sensitivity infrared (IR) sensors in order to detect very low incident fluxes. Laser gated imaging has, in particular, additional specific needs. IR sensors for this type of application are synchronized with eye-safe lasers, and have to detect a weak signal backscattered from the target on the order of 10 photons per pulse. They also have to be able to operate with a very short integration time, typically one hundred nanoseconds, to gate the backscattered signal around the target. This paper describes the road-map to address low flux infrared sensors in the next few years.

Sofradir MCT technology for space applications
Author: Philippe Chorier
Published 6 May 2009
Sofradir is one of a leading company of the world for the development and production of infrared detectors. Main applications of these detectors are tactical and commercial applications but also space applications including earth observation that began in 1990. Sofradir’s has developed a capability to develop a large panel of high reliable detectors like long linear arrays or two dimensional arrays covering bandwidth from visible to 15 μm based on qualified Mercury Cadmium Telluride (MCT) technology. This paper describes Sofradir’s involvement in several projects for future space missions (SPIRALE, Sentinel-2 for GMES, MTG, SGLI...) covering a spectral range from visible to long wavelength infrared. The paper reviews Sofradir technology for the development and manufacturing of infrared detectors for space applications with particular emphasis on the different programs currently run with a presentation of the associated results in terms of performances and qualifications for space use.

Latest results of SOFRADIR MCT technology for space applications
Authors: L. Vial, P. Chorier, O. Gravrand
Published 9 October 2008
Vol. 7106: Sensors, Systems, and Next-Generation Satellites XII
This paper describes Sofradir’s developments of high reliability Mercury Cadmium Telluride (MCT) with different formats covering bandwidths from visible to over 15 μm. Specifically, the latest developments concern the extension, characterization and improvement of the MCT technology into the visible range for hyperspectral and spectroscopy needs as well as continuing development of detectors with long-wave cut-off wavelength (above 13 μm) for future space applications like meteorology, for example.

HgCdTe APD- focal plane array development at CEA Leti-Minatec
Authors: Johan Rothman, Gwladys Perrais, Eric De Borniol, et al.
Published 5 May 2008
Vol. 6940: Infrared Technology and Applications XXXIV
We report the latest developments of MW HgCdTe electron initiated avalanche photo-diodes (e-APDs) focal plane arrays (FPAs) at CEA-LETI. The MW e-APD FPAs are developed in view of ultra-sensitive high dynamic range passive starring arrays, active 2D/3D and dual-mode passive-active imaging, which is why both the passive imaging performance and the gain characteristics of the APDs are of interest. A passive mode responsivity operability of 99.9% was measured in LPE and MBE e-APDs FPAs associated with an average NETD=12mK, demonstrating that dual mode passive-active imaging can be achieved with LETI e-APDs without degradation in the passive imaging performance.

IR detectors design and approach for tactical applications with high reliability without maintenance
Authors: Xavier Breniere, Philippe Tribolet
Published 2 May 2008
Vol. 6940: Infrared Technology and Applications XXXIV
Tactical applications require that IR detectors have low frequency of maintenance as well as predictable maintenance location. Maintenance has a cost that becomes quickly prohibitive when the cooler or the vacuum needs to be frequently repaired. After many years of research, Sofradir reports on reliability and life cycle cost optimization considering all the IR detectors subassemblies. This work has lead to an increased robustness of detectors and technologies even under severe environmental conditions, and reduced variability in production. This paper presents the state of the art of Integrated Detector Dewar Cooler Assembly (IDDCA)'s reliability, the production means and the methods that allow us today to propose detectors with very high reliability without maintenance. These detectors are a breakthrough for life cycle cost for tactical applications as portable cameras, airborne systems, and missiles.

Advanced HgCdTe technologies and dual-band developments
Authors: Philippe Tribolet, Gérard Destefanis, Philippe Ballet, et al.
Published 18 April 2008
Vol. 6940: Infrared Technology and Applications XXXIV
The Molecular Beam Epitaxy (MBE) approach was under investigation for several years to prepare both the very large array fabrication and the 3rd generation developments. This large step in Infrared (IR) detector mass production is also necessary for producing third generation of IR detectors such as bicolor and dual band FPAs which use more complex multi hetero-junctions architectures. These new advanced HgCdTe technologies necessary for third generation developments have been validated and their producibility have been improved. As far as dual band IR detectors are concerned, the technologies are developed and a full TV format (24μm pixel pitch) is currently under development with a first application in bicolor within medium waveband. Future improvements including avalanche photodiodes (APD), will lead to more compact systems as well as a low cost approach.

State-of-the-art of mass production: challenges for low-cost and application benefits of high-performances small-pitch IR detectors
Authors: Emmanuel Bercier, Jean Luc Dessus, Alain Manissadjian, et al.
Published 15 April 2008
Vol. 6940: Infrared Technology and Applications XXXIV
HgCdTe (Mercury Cadmium Telluride / MCT) staring arrays for infrared detection do show constant improvements regarding their compactness and performances. New detectors are now proposed offering system solutions in the different IR wavebands and taking advantage of the latest technology improvements as well as MCT performance advantages and cost reduction. Based on 20 years of experience in 50μm to 15μm pitch Infrared (IR) detector production, the challenge of mass production of low-cost small-pixel pitch detectors are reviewed, from the IR chip manufacturing including detection material, hybridization, ROIC, to the integration in final packing. Taking advantage of its simple well known existing process, then the analyzes of all technological steps adapted to small pitch IR detector are presented, in terms of product performance, reliability, process statistics and capability in order to achieve high yield and low product cost. Answers given the low-cost small-pitch IR detector mass productions finally give benefits to application in terms of high performance, cost reduction, extended life time, and on the field system Life Cycle Support Among these new detectors, one can find the family of 15 μm pixel pitch detectors a TV format (640 x 512) integrated in dedicated tactical Dewars, taking advantages on last development in coolers manufacturing and Dewar assembly.