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Vuillermet M.,SOFRADIR
Defence Science Journal | Year: 2013

This short article describes the recent developments of cooled infrared products at Sofradir. These developments are driven by the future systems needs like the increase in resolution and detection range, the reduction of the detector size and consequently of the pixel pitch and the reduction of the power consumption. To answer to these needs, Sofradir develops in collaboration with the French infrared laboratory (CEA-LETI) new products based on Mercury Cadmium Telluride technology: Scorpio LW 640 × 512/15 μm pitch, sensitive in the long wavelength, Jupiter MW 1280 × 1024/15 μm pitch sensitive in mid wavelength, HOT detectors operating at 150 K and the 10 μm pitch detectors. © 2013, DESIDOC.

Gravrand O.,CEA Grenoble | Mollard L.,CEA Grenoble | Boulade O.,CEA Saclay Nuclear Research Center | Moreau V.,CEA Saclay Nuclear Research Center | And 2 more authors.
Journal of Electronic Materials | Year: 2012

We report the first results of work carried out at CEA and Sofradir to build ultralow-dark-current focal-plane arrays (FPAs) in the short-wave infrared range (SWIR) for space applications. These FPAs are designed to detect very low flux in the 2-μm wavelength range. To this end, Sofradir has designed a source follower per detector read-out circuit (ROIC, 384 × 288, 15 μm pitch). This ROIC has been hybridized on different HgCdTe diode configurations processed at CEA-LETI, and low-flux characterizations have been carried out at CEA-IRFU at low temperature (from 60 K to 160 K). Both ion-implanted p/n and n/p diodes have been evaluated. The metallurgical nature of the absorbing layer has also been examined, and both molecular-beam epitaxy (MBE) and liquid-phase epitaxy (LPE) have been applied. Dark-current measurements are discussed in comparison with previous results from the literature. State-of-the-art dark currents are recorded for temperatures higher than 120 K. At temperatures lower than 100 K, the decrease in dark current flattens out for both technologies. In this region, currents between 0.4 e -/s/pixel and 0.06 e -/s/pixel are reported. © 2012 TMS.

Berthoz J.,SOFRADIR | Rubaldo L.,SOFRADIR | Grille I.R.,SOFRADIR | Gravrand O.,CEA Grenoble
2014 11th International Workshop on Low Temperature Electronics, WOLTE 2014 | Year: 2014

Reduction of pixel pitch in infrared detector improves the spatial resolution and the range. The key performance of the detector range is the modulation transfer function (MTF). In an ideal case MTF can be express as the Fourier transformation of its square response. For small pixel, electrical lateral diffusion tends to reduce MTF from its ideal value. Computation shows that at 10μm the MTF is better than at 15μm for a given frequency. However, because of electric lateral diffusion, MTF at 10μm is more distant from its ideal value. Computations show that mesa can be used to have a better MTF. © 2014 IEEE.

Vuillermet M.,SOFRADIR | Tribolet P.,SOFRADIR
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

Cooled IR technologies are challenged for answering new system needs like the reduction of energy. This reduction is requested in new IR system design 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. 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. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Brellier D.,CEA Grenoble | Gout E.,CEA Grenoble | Gaude G.,CEA Grenoble | Pelenc D.,CEA Grenoble | And 3 more authors.
Journal of Electronic Materials | Year: 2014

We report the bulk growth of single-crystal CdZnTe and characterization of material associated with large-area wafers produced from the CdZnTe ingots. Our experimental vertical gradient freeze set-up enables accurate detection of the beginning and end of the crystallization step by careful monitoring of the thermal cycle. Single crystal, (111)-oriented ingots with a diameter of 80 mm were routinely obtained without grain boundary or twin. The size of the CdZnTe ingots was extended to 115 mm in diameter, enabling production of large-dimension substrates suitable for infrared focal-plane arrays with megapixel-resolution. Crystal quality was investigated by double-crystal x-ray rocking curve mapping and by chemical revelation of etch pits. Typical mean values for the rocking curve full width at half maximum were in the range 20-40 arcs. Evaluation of etch pit density on the (111)Te face furnished values in the low 104/cm2. © 2014 TMS.

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