T2SL development for space at IRnova: from eSWIR to VLWIR

In this paper, results from the development of InAs/GaSb superlattice focal plane arrays (FPAs) at IRnova will be presented. A versatile and robust detector design is used that allows for adjustment of the detection cut-off wavelength from 2.5 mu m up to 14.5 mu m with only minor changes in the detector design. Performance of the fabricated detectors has been reviewed in terms of external quantum efficiency (EQE), dark current and noise for three designs with cut-off wavelengths of 4, 5.5 and 11 mu m at 80 K (referred to as DEEP BLUE, RED HOT and VLWIR, respectively). Measurements on the 15 mu m sized photodiodes demonstrated 70 % EQE for the MWIR designs, and almost 40 % for VLWIR. At the same time, the dark current stayed close to the Rule07 benchmark for all studied samples. Noise mechanisms have been discussed and their relation to the passivation was examined. Mature in-house processing and passivation technique resulted in very high spatial uniformity of VGA focal plane arrays (FPAs), i.e. low relative deviations of EQE (< 6 %) and of dark current density (< 12 %), and narrow noise distributions for both RED HOT and DEEP BLUE FPAs. We show also that >99.5 % of these arrays operate close to the fundamental noise limit.