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| High Performance Infrared Imaging |
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Due to strong demand for improved EOIR performance, new cooled technology has brought new capabilities for infrared imaging. Infrared (IR) systems are now present in a diverse range of applications in military, space and commercial areas. With the improvements in technology, system designers are also seeking to add new features and capabilities to develop highly innovative products.
Military, commercial and space applications require very different infrared subsystem characteristics in terms of reliability, cooling, format size and other performance criteria. Sofradir meets these demands by adapting its products to best suit customer requirements and by developing new designs that anticipate customer needs in the future. Sofradir technology is at the forefront of these trends. |
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| Military Applications |
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| Sofradir IR detectors have been deployed in thermal imaging cameras, Forward Looking Infrared (FLIR) systems, missile seekers and other surveillance targeting and homing infrared equipment. Long recognized as a leader in the field, Sofradir continues to be involved in most of the important IR detector projects for major programs in Europe, as well as other military projects around the world. Sofradir detectors have been deployed in battlefield equipment and proven many times in operation. Examples of major programs that use Sofradir detectors include the Storm Shadow/SCALP EG IR missile seeker, Damocles targeting and NAVFLIR navigation pods, Sophie hand held goggles, IRIS cameras, SADA II (Standard Advanced Dewar Assembly deployed in Bradley and Abrams, US armored vehicles) and ARTEMIS (deployed on FREMM vessel). |
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| Space Applications |
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| Sofradir stands out since it is one of the only companies to have second-generation IR detectors on-board satellites (Venus Express, Helios II, Spirale). Working in close cooperation with national space agencies and companies worldwide, Sofradir's MCT IR detectors today observe deep space, perform Earth mapping, environment and disaster monitoring, and provide data on meteorological phenomena. Due to the flexibility of MCT technology and the high reliability of the hybridization process, Sofradir is able to offer space qualified detectors that cover a wide spectral range from the visible to 15µm, in linear or area array format, with long-life coolers or without coolers for passive cooling. A dedicated team of project managers familiar with infrared imagers for space applications are available to interface with each customer – from specification discussion to final delivery – whether the project is a custom design or the upgrade of an existing system. |
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| Commercial Applications |
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In parallel to its product developments in the defense market, Sofradir has for many years also developed a range of products in the short wave, mid wave and long wave specially adapted for commercial applications, such as:
- Scientific Research
- Spectroscopy
- Process control
- Gas detection
These application areas cover numerous markets and Sofradir detectors are already in use in the paper industry, automotive manufacturing, gas detection, process control and IR inspection in product design, test and manufacturing. |
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The Factory |
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Our cooled
detectors are made by our
parent company, Sofradir SAS,
located outside Grenoble, France. |
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Sofradir
SAS develops and manufactures advanced infrared
detectors for military, space and commercial applications.
The company specializes in cooled IR detectors based
on a sophisticated high performance Mercury Cadmium
Telluride (MCT) technology. Since the company’s
founding in 1986, Sofradir SAS has pioneered the
development of second- and third-generation MCT
IR detectors, and secured a vast product portfolio
of scanning and staring arrays that covers the entire
infrared spectrum using MCT, quantum well infrared
photodetectors (QWIP) as well as microbolometer
technology platforms.
Sofradir SAS is the first company to
successfully develop MCT technology and bring its industrial
processes to maturity. It is among the very few who
can produce large quantities of second-generation and
third-generation IR detectors. In 2008, Sofradir SAS
employed over 400 people and was considered the No.
1 supplier in Europe for high-grade IR detectors for
application in thermal imagers, missile seekers, and
other surveillance, targeting and homing infrared equipment,
based on their historical deliveries of cooled MCT second-generation
IR detector units. In addition, Sofradir also holds
a unique position in Europe as the only company to have
developed, qualified and deployed space-grade second
generation IR detectors. Working in close cooperation
with national space agencies and companies worldwide,
Sofradir's MCT IR detectors today observe deep
space, observe Earth, monitor the environment, and provide
data on meteorological phenomena.
To stay at the forefront of IR detection,
Sofradir invests significantly in research and development.
Their team of experienced engineers and technicians
works in partnership with scientists at the Infrared
Research Laboratory (LETI/LIR), the most advanced lab
in Europe, to advance their MCT technology. The team
anticipates future optronics defense system requirements
and develops new solutions to address these needs. As
a consequence, Sofradir has been able to deliver a number
of "firsts" to the market, and offer products
that give customers a competitive edge. |
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Recent Sofradir SAS Research Papers |
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| Improved IR detectors to swap heavy systems for SWaP |
| Authors: Alain
MANISSADJIAN, Laurent RUBALDO, Yann REBEIL, Alexandre
KERLAIN; Delphine BRELLIER, Laurent
MOLLARD Published
1 May 2012 |
Cooled IR technologies are challenged for answering new system needs like the compactness and the reduction of cryopower which is a key feature for the SWaP (Size, Weight and Power) requirements. Over the last years, SOFRADIR has improved its HgCdTe technology with an impact on dark current reduction, opening the way for High Operating Temperature (HOT) systems that can overcome the previous 80K FPA temperature constraint resulting in lower Stirling cooler power consumption. Performance of the 640x512 15μm pitch LW detector working above 100K will be presented as well as a compact 640x512 15μm pitch MW detector (cut-off wavelength >5.0μm) working above 130K. Pixel pitch reduction solutions will also be discussed for resolution enhancement and further size reduction. |
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| LWIR and VLWIR MCT technologies and detectors development at SOFRADIR
for space applications |
| Authors: Cédric Leroy, Philippe Chorier; Gérard Destefanis Published
1 May 2012 |
The paper describes SOFRADIR's involvement in the development and manufacturing of MCT (Mercury Cadmium Telluride) infrared detectors for space programs. SOFRADIR is involved is a wide range of applications covering a large spectrum from visible to very long wavelength infrared (VLWIR). The latest mission requirements have delivered new specifications for LWIR and VLWIR infrared detectors with cut-off wavelength of higher than 15 μm. These requirements call for technology and design optimizations in order to identify the best trade-off between detector performances and operational constraints such as operating temperature. This paper presents a review of the different needs for current and future LWIR and VWLIR space applications in terms of detector architecture and requirements. The paper also presents the latest MCT technology optimizations for LWIR and VLWIR spectral bandwidths to meet these needs (n-on-p and p-on-n technologies). Finally, different read-out circuit architectures are discussed to improve operability and performances in these bandwidths. |
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| Status of MCT focal plane arrays in France |
Authors: M. Vuillermet, D. Billon-Lanfrey, Y. Reibel, A. Manissadjiana; L. Mollard,
N. Baier,
O. Gravrand and G. Destéfanis Published
1 May 2012 |
| This paper describes the recent developments of Mercury Cadmium Telluride (MCT) infrared technologies in France at Sofradir and CEA-LETI made in the frame of the common laboratory named DEFIR. Among these developments, one can find the crystal growth of high quality and large Cadmium Zinc Telluride (CZT) substrates which is one of the fundamental keys for high quality and affordable detectors. Technology improvements to MCT epitaxy layer processes have been required in order to achieve High Operating Temperature (HOT) performance. Over these last few years, the operating temperature of n-on-p MCT detectors has increased several tens of Kelvin. With the development of p-on-n MCT technology that reduces dark current by a factor about 100, an additional increase in operating temperature has been achieved. The next step for the increase in operating temperature will be the complex photodiode architecture using the molecular beam epitaxy layer. The reduction of the pixel pitch is another challenge for infrared technologies for Small Weight and Power (SWAP) detectors that allows for the increase in resolution and detection range. In addition, latest results on 3rd generation detectors such as multicolor focal plane arrays, 2D, 3D, low noise and high frame rate focal plane arrays using Avalanche Photodiode (APD) are described. |
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| Small
pixel pitch solutions for active and passive imaging |
| Authors: Yann Reibel; Alexandre Kerlain; Gwladys Bonnouvier; David Billon-Lanfrey; Johan Rothman; Laurent Mollard; Eric de Borniol; Gérard Destefanis Published
1 May 2012 |
| An update regarding Sofradir's detectors for space activities, especially incorporated into meteorological instruments using imagery or spectrometry. One example described is pre-development activities for Meteosat's Third Generation mission, ESA, to address the critical equipment required for risk reduction. VLWIR detectors for FCI and IRS have been considered as challenging ones for which SOFRADIR is involved in manufacturing and testing 2-D arrays with a long wave cut-off of 14.9μm at 50K in order to evaluate their compliance to MTG requirements as far as dark current behavior, quantum efficiency, photoresponse uniformity, spatial response, operability and reliability are concerned. In parallel, trends of space and tactical applications call for dark current reduction technology in order to improve systems performances in terms of operating temperature and signal to noise ratio. |
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| QWIP
infrared detector production line results |
| Authors: Michel Runtz ; Franck Perrier ; Nicolas Ricard ; Eric Costard ; Alexandru Nedelcu ; Vincent Guériaux Published
1 May 2012 |
| Since 1997, Sofradir and Thales Research & Technologies (TRT) have been working together to develop and produce Quantum Well Infrared Photodetectors (QWIP) to provide large LW staring arrays. Because of the low dark current technology developed by TRT, the QWIP detectors can be operated at FPA temperatures above 73K, enabling the production of compact IR cameras with compact microcoolers. The TV/2 VEGA-LW detector (25μm pitch 384x288 Integrated Detector Dewar Assembly) is integrated into the Catherine-XP thermal imager from Thales Optronique SA (TOSA). To date, more than one thousand units have been manufactured. The TV SIRIUS-LW detector (20μm pitch 640x512 IDDCA) is integrated in the Catherine-MP thermal imager from Thales Optronics Ltd. (TOL). To date, several hundreds of units have been manufactured. This paper will describe the statistical results of this production including the latest reliability study results which highlight the stability of the TRT QWIP technology. Because of the mature nature of the technology, TRT and Sofradir have been able to increase the QWIP wafer size from 3 inches to 4 inches without any impact on yield and FPA performance. A dual-band Mid Wave-Long Wave (MW-LW) QWIP detector (25μm pitch 384x288 IDDCA) is also described. |
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| Sofradir
detectors for hyperspectral applications from visible
up to VLWIR |
| Authors: Bruno
Fièque, Philippe Chorier, Bertrand Terrier Published
13 October 2010 |
| Sofradir has extended
its Visible-Near infrared technology, called VISIR,
largely as a result of its participation in the PRISMA
mission. This technology has been specially developed
for hyperspectral applications and enables detection
in both visible range and SWIR detection range (0.4μm
up to 2.5μm). Sofradir has developed MCT detectors
that cover MWIR and LWIR infrared ranges, ideal for
space applications. For example, 1000x256 (Saturn)
and 500x256 arrays (Neptune) 30μm pitch detectors
have already been validated in terms of irradiation
behavior, thermal cycling, and ageing. In addition,
Sofradir now offers a large MWIR or LWIR 1016x440
array with a 25μm pixel pitch for hyperspectral
imaging. |
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| Operating
temperature: A challenge for cooled IR technologies |
| Authors: Michel
Vuillermet, Philippe Tribolet. Published
3 May 2010 |
| Cooled IR technologies
are challenged for answering new system needs like
the reduction of power. This reduction is requested
in new IR system designa in particular for cooled
IR detection. The goal is to reduce system sizes,
to increase system autonomies and reliabilities and
globally to reduce system costs. One of the key drivers
for cooled systems is the cooler and the operating
temperature of the detector. As far as operating temperature
is concerned, Sofradir put a lot of efforts for years
for adapting its technologies to increase the operating
temperatures of IR detectors. Main examples are dealing
with long wave staring arrays based on QWIP technology
and on MCT technology as well as medium wave staring
arrays using MCT technologies. |
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| New
IR detectors with small pixel pitch and high operating
temperature |
| Authors: David
Billon-Lanfrey, Philippe Trinolet, Frédéric
Pistone, et al. Published 15 December
2010 |
| More and more systems
are requested to be more compact keeping constant
system performance. One of the best strategies is
to reduce the pixel pitch of the IR detector while
new technology improvements are carried out to improve
the detector performance. The latest developments
at SOFRADIR / France for cooled IR detectors are following
these trends. HgCdTe (Mercury Cadmium Telluride /
MCT) staring arrays for infrared detection do show
constant improvements regarding their compactness
by reducing the pixel pitch, and regarding performances.
Among the new detectors, the family of 15μm pixel
pitch detectors is offering a mid-TV format (384x288),
a TV format (640x512) and a HD-TV format (1280x1024).
The latest development concerning the mid-TV format
is performed according to very challenging specifications
regarding compactness and low power consumption. Thanks
to recent improvements, the MCT technology allows
to operate detectors at higher temperature (HOT detectors),
in order to save power consumption at system level.
In parallel, the 15μm pitch permits to reach challenging
density and spatial resolution. These Focal Plane
Arrays (FPA) are proposed in different tactical dewars,
corresponding to various systems solutions. |
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| A
25μm pitch LWIR staring focal plane array with
pixel-level 15-bit ADC ROIC achieving 2mK NETD |
| Authors: Sylvette
Bisotto, Eric de Borniol, Laurent Mollard, et al. Published
27 October 2010 |
| CEA-Leti MINATEC
describes recent trends to integrate advanced functions
into IR FPA CMOS designs for the purpose of applications
demanding a breakthrough in NETD performance or a
high dynamic range with high-gain APDs. This paper
presents a mid-TV format FPA operating in LWIR with
25μm pixel pitch, including a new readout IC (ROIC)
architecture based on pixel-level charge packets counting.
The ROIC has been designed in a standard 0.18μm
6-metal CMOS process, LWIR n/p HgCdTe detectors were
fabricated with CEA-Leti in-house process. The FPA
operates at 50Hz frame rate in a snapshot integrate-while-read
(IWR) mode, allowing a large integration time. While
classical pixel architectures are limited by the charge
well capacity, this architecture exhibits a large
well capacity (near 3Ge-) and the 15-bit pixel level
ADC preserves an excellent signal-to-noise ratio (SNR)
at full well. These characteristics are essential
for LWIR FPAs as broad intra-scene dynamic range imaging
requires high sensitivity. The main design challenges
for this digital pixel array (SNR, power consumption
and layout density) are discussed. The electro-optical
results demonstrating a peak NETD value of 2mK and
images taken with the FPA are presented that validate
both the pixel-level ADC concept and its circuit implementation.
A previously unreleased SNR of 90dB is achieved. |
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