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HgCdTe APD- focal plane array development at CEA Leti-Minatec
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Paper Abstract

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. The gain and sensitivity performances were measured in test arrays and using a low voltage technology (3.3V) CTIA test pixel designed for 3D active imaging. The CTIA and test arrays measurements yielded comparable results in terms of bias gain dependence (M=100 at Vb=-7V), low excess noise factor (=1.2) and low equivalent input current (Ieq_in<1pA). These results validated the low voltage CTIA approach for integrating the current from a HgCdTe e-APD under high bias. The test array measurements demonstrated a relative dispersion below 2% in both MBE and LPE e- APDs for gains higher than M>100, associated with an operability of 99%. The operability at Ieq_in<1pA at M=30 was 95%. A record low value of Ieq_in=1fA was estimated in the MBE e-APDs at M=100, indicating the potential for using the MW e-APDs for very low flux applications. The high potential of the MW e-APDS for active imaging was demonstrated by impulse response measurements which yielded a typical rise time lower than 100ps and diffusion limited fall time of 900ps to 5ns, depending on the pixel pitch. This potential was confirmed by the demonstration of a 2ns time of flight (TOF) resolution in the CTIA e-APD 3D pixel. The combined photon and dark current induced equivalent back ground noise at f/8 with a cold band pass filter at λ=1.55μm was 2 electrons rms for an integration time of 50ns.

Paper Details

Date Published: 5 May 2008
PDF: 12 pages
Proc. SPIE 6940, Infrared Technology and Applications XXXIV, 69402N (5 May 2008); doi: 10.1117/12.780447
Show Author Affiliations
Johan Rothman, CEA - LETI - Minatec (France)
Gwladys Perrais, CEA - LETI - Minatec (France)
Eric De Borniol, CEA - LETI - Minatec (France)
Pierre Castelein, CEA - LETI - Minatec (France)
Nicholas Baier, CEA - LETI - Minatec (France)
Fabrice Guellec, CEA - LETI - Minatec (France)
Michael Tchagaspanian, CEA - LETI - Minatec (France)
Philippe Ballet, CEA - LETI - Minatec (France)
Laurent Mollard, CEA - LETI - Minatec (France)
Sylvain Gout, CEA - LETI - Minatec (France)
André Perez, CEA - LETI - Minatec (France)
Maryse Fournier, CEA - LETI - Minatec (France)
Jean-Paul Chamonal, CEA - LETI - Minatec (France)
Philippe M. Tribolet, Sofradir - BP 21 (France)
Gerard Destefanis, CEA - LETI - Minatec (France)

Published in SPIE Proceedings Vol. 6940:
Infrared Technology and Applications XXXIV
Bjørn F. Andresen; Gabor F. Fulop; Paul R. Norton, Editor(s)

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