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Recent development in infrared technologies at LETI for Earth observation
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Paper Abstract

In this paper we report on the CEA/LETI infrared laboratory activity in both HgCdTe cooled detectors and amorphous silicon uncooled microbolometers. An overview of the recent developments will be given while the future perspectives of these IR technologies will be highlighted in the context of space applications. The unique realization of a megapixel HgCdTe MWIR focal plane array with a 15μm pitch was completed in 2003. The electro-optical performances at LN temperature of this high resolution IRFPA will be given extensively. Beside this large 2D array achievement, CEA/LETI is strongly involved in the development of an innovative cooled multispectral technology that requires a specific HgCdTe growing process to achieve a stack of two dual band photodiodes in each pixel. This technology primarily relies on the molecular beam epitaxy (MBE) of a multiple (211)HgCdTe films grown on a lattice matched CdZnTe substrate. The device structure will be discussed as well as the elementary detectors characteristics which have been found to exhibit performances very close to those obtained in single colour detectors. The main electro-optical performances obtained at LN temperature of a two colours 128x128 IRCMOS FPA, 50μm pitch, operating sequentially within the MWIR (3-5μm) will be presented. The well establish availability of uncooled infrared detectors has opened new perspectives when miniaturization, weight, power and reliability are of paramount importance. Moreover the recent breakthrough of the performance of these sensors leads to new applications where enhanced resolution is required. The article will review the state of the art of CEA/LETI uncooled IR technology through various examples of focal plane arrays and the future trends of this uncooled technology will be considered. The trade-off between thermal resolution and time constant which is a critical parameter for earth observation will be largely discussed.

Paper Details

Date Published: 4 November 2004
PDF: 12 pages
Proc. SPIE 5570, Sensors, Systems, and Next-Generation Satellites VIII, (4 November 2004); doi: 10.1117/12.565530
Show Author Affiliations
Jean Jacques Yon, CEA-LETI (France)
Gerard Destefanis, CEA-LETI (France)
Eric Mottin, CEA-LETI (France)

Published in SPIE Proceedings Vol. 5570:
Sensors, Systems, and Next-Generation Satellites VIII
Roland Meynart; Steven P. Neeck; Haruhisa Shimoda, Editor(s)

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