Developments of short-wave infrared InGaAs focal plane detectors

Abstract

SWIR InGaAs FPAs are widely applied to space remote sensing, low light level night vision and medical diagnostics due to the high detectivity and uniformity. Highly sensitive NIR InGaAs FPAs with response covering from 0.9 μm to 1.7 μm, the extended SWIR InGaAs FPAs with the cutoff wavelengths from 1.0 μm to 2.5 μm, and other novel SWIR InGaAs FPAs have been studied respectively at Shanghai Institute of Technical Physics of Chinese Academy of Sciences over the past ten years. NIR InGaAs FPAs have developed from some typical linear 256×1, 512×1 FPAs to 2D format 320×256, 640×512, 4 000×128 and 1 280×1 024 FPAs. Typically, the dark current density was about 5 nA/cm2 and the peak detectivity was superior to 5×1012 cm·Hz1/2/W at room temperature. 2D format 1 024×256, 1 024×512 extended wavelength InGaAs FPAs with high frame rate were also developed for the hyperspectral applications at SITP. The dark current density drops to 10 nA/cm2 and peak detectivity was over 5×1012 cm·Hz1/2/W at 200 K. By using novel epitaxial materials and the light trapping structures, the visible-NIR InGaAs FPAs for wavelength band of 0.4-1.7 μm have also been developed. The as-prepared 320×256, 640×512 InGaAs FPAs were obtained with quantum efficiency superior to 40%@0.5 m, 80%@0.8 m and 90%@1.55 m. For polarimetric detecting, InGaAs devices integrated with sub-wavelength metal grating of different angles (0°, 45°, 90°, 135°) have been developed, which exhibit the extinction ratio of greater than 20:1.