Ultra low dark current CdHgTe FPAs in the SWIR range at CEA and Sofradir
Proc. SPIE 8176, 81761H (2011); doi:10.1117/12.901864
Online Publication Date: Wednesday 02 November 2011
Conference Date: Monday 19 September 2011
Conference Location: Prague, Czech Republic
Conference Title: Sensors, Systems, and Next-Generation Satellites XV
Conference Chairs: Roland Meynart, Steven P. Neeck, Haruhisa Shimoda
O. Gravrand, L. Mollard, O. Boulade, and G. Destéfanis
Commissariat à l'Énergie Atomique, LETI (France)
CEA-IRFU-Service d'Astrophysique (France)
We report here first results carried out at CEA and Sofradir to build ultra low dark current focal plane arrays (FPA) in the short wave infrared range (SWIR) for space applications. Those FPAs are dedicated to very low flux detection in the 2?m wavelength range. In this purpose, Sofradir has designed a source follower per detector readout circuit (ROIC), 384x288, 15?m pitch. This ROIC has been hybridized on different HgCdTe diode configurations processed at CEALETI and low flux characterisations have been carried out at CEA-SAp at low temperature (from 60 to 160K). Both p/n and n/p structures have been evaluated. The metallurgical nature of the absorbing layer is also examined and both molecular beam epitaxy (MBE) and liquid phase epitaxy (LPE) have been processed. 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 120K. At temperatures lower than 100K, the decrease in dark current saturates for both technologies. In this regime, currents between 0.4 and 0.06 e/s/pixel are reported.
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O. Gravrand, L. Mollard, O. Boulade, V. Moreau, E. Sanson and G. Destéfanis, "Ultra low dark current CdHgTe FPAs in the SWIR range at CEA and Sofradir", Proc. SPIE 8176, 81761H (2011); doi:10.1117/12.901864