Extended Short Wavelength Infrared In0.83Ga0.17As Focal Plane Array

We present the detailed characteristics of solid source molecular beam epitaxy (MBE) grown large format (640 × 512) extended short wavelength infrared In0.83Ga0.17As sensor with desirable performance at both pixel and focal plane array (FPA) levels. The FPA pixels in the mesa structure grown on a graded AlInAs buffer layer with 2.65-μm, 300-K cutoff wavelength exhibited 300and 200-K peak detectivities as high as ~2.5×10¹⁰ and ~1×1012 cmHz^1/2/W, which are both equivalent to the theoretical limits set by the Johnson noise of the detector. Dark current analysis of the pixels displayed no considerable tunneling component with the dark current being dominated by generation-recombination and shunt leakage mechanisms >200 K up to a reverse bias voltage of 3 V. Moreover, the noise measurements displayed no 1/f noise in the FPA pixels. In spite of the large lattice mismatch, the FPA yielded very good response linearity, as well as impressively good responsivity nonuniformity and pixel operability of 5.5% and 99.8%, respectively. The results showing the feasibility of both solid source MBE and graded AlInAs buffer for the growth of extended InGaAs photodetectors are very encouraging for the large format FPA implementation of these detectors with desirable imaging performance and an extended cutoff wavelength as high as ~2.7 μm.