IR photodetector arrays based on HgCdTe films and GaAs/AlGaAs multiquantum wells

Abstract

A technology was designed and the photodetector modules were manufactured for the 3-5 and 8-12 micrometers spectral range based on the Hg<SUB>1-x</SUB>Cd<SUB>x</SUB>Te/GaAs heterostructures and GaAs/AlGaAs multiquantum well structures grown by the molecular beam epitaxy method. The photosensitive HgCdTe layers were grown on the GaAs substrates with the intermediate buffer layer of CdZnTe. To decrease the surface influence on the recombination processes graded gap HgCdTe layers with the increase to the surface composition were grown. A silicon multiplexer was designed and manufactured on the CMOS/CCD technology with frame rate 50 Hz. Hybrid assembly of the photodetectors array and the multiplexer was produced by the group cold welding on the indium bumps with control of the connection process. The manufactured 128 x 128 FPAs on the HgCdTe with the cut- off wavelength 6 micrometers and 8.7 micrometers had the NEDT value 0.02 K and 0.032 K, correspondingly, at operating temperature 78K and frame rate 50Hz. The photosensitive GaAs/AlGaAs multiquantum well structures were manufactured by the MBE method. It is shown that the designed technology allows to produce 129 x 128 photodetector arrays ((lambda) <SUB>max</SUB>=8 mum) with the NEDT value 0.021 K and 0.06 K at operating temperature of 54 K and 65 K, correspondingly.