T2SL production and development at IRnova: From MWIR to VLWIR detection

Development towards higher operating temperature, smaller pitch and larger format arrays is ongoing for midwave (MW) InAs/GaSb superlattice detectors at IRnova. One part of this effort entails improvement in the MW detector design, which has resulted in increased quantum efficiency to 55-60 % in the entire 3-5 μm wavelength region, with dark current levels lower than 3×10^-6 A/cm² at 120 K. Furthermore, MW-MW dual band detectors have been realized by using pixel filters fabricated on top of regular MW FPAs. The pixel filters were designed to transmit infrared radiation in the 3.5 μm - 4.1 μm wavelength region and to completely block light shorter than 3.5 μm. By comparing the signals of filtered and unfiltered pixels, excellent contrast between the two bands were obtained. Long wave infrared detectors have also been realized with cut-off wavelength at 12.2 μm and dark current levels following the Rule07 trendline from 80 K to 160 K, with only two times higher dark current than Rule07 at 80 K.