Noise behaviors of SWIR InxGa1-xAs/InP focal plane arrays as a function of lattice-mismatch degree

Abstract

A quantitatively investigation on the dark noise behaviors of In0.53Ga0.47As/InP, In0.75Ga0.25As/In0.75Al0.25As/InP and In0.83Ga0.17As/In0.83Al0.17As/InP short-wavelength infrared (SWIR) focal plane arrays (FPAs) with cutoff wavelengths (λc) of 1.7, 2.2 and 2.5 μm, respectively, is presented. Theoretical FPA noise model consisting of the diode thermal noise, the dark current shot noise, the operational transimpedance amplifier (OTA) thermal noise, the 1/f noise, the sample and hold noise of the circuit, and etc. were fully taken into consideration. The results show that the dark noises are mainly composed of the OTA thermal noise of the readout circuit under short integration times (Tint) for all three FPAs. Under long Tint, the thermal noises from the photodiode arrays at 300 K is acting as the primary source for the dark noise of the lattice-matched In0.53Ga0.17As FPA, whereas noises of the lattice-mismatched 2.2 and 2.5 μm FPAs are identified to be mainly comes from the diode thermal noise, the dark current shot noise, and the 1/f noise at 150 and 180 K. In addition, an overall trend that the contribution of the 1/f noise increases significantly even if the junction impedance increases and the dark current decreases by cooling down for the extended wavelength detector, which is related to the existence of high density misfit dislocation defect-related trap states in the materials. These results suggest that lowering the junction capacitance and increasing the junction resistance are effective routes to suppress the total readout noise of the InGaAs FPAs, which essentially relies on the improvements on the material epitaxial growth and photodiode array processing recipes.Index Terms: readout noise, lattice-mismatch, focal plane array, InGaAs, noise model.