Active surface passivation for SWIR InGaAs photodetectors

Necati, Işık
This thesis work offers a new method for improving one of the performance parameters in infrared photodetector technology. This method involves suppressing the surface dark current by utilizing a constant E-field on the surface of the photodetector. By interrupting the channel formation on the surface, a significant improvement in the generation-recombination (GR) dark current component is observed. Relatively minor improvements on differential resistance and the shunt component of the dark current are noted. Lattice-matched short-wave infrared (SWIR) Indium-Gallium-Arsenide (InGaAs) grown on Indium-Phosphide (InP) sample with a cut-off wavelength of 1.7 μm is processed with wet etching of 30 μm pixel pitch to verify this claim. The proper operation of the photodetector is verified using responsivity measurements. Reported total dark currents reduced from 195 pA to 70 pA per pixel with -0.1 V bias at 300 K temperature and 175 pA to 39 pA per pixel at 290 K. Using the dark current modeling, determined GR currents observed to be decreased by more than 90%. The feasibility of this phenomenon discussed whether to be implemented to the standard focal plane array (FPA) processes.


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Citation Formats
I. Necati, “Active surface passivation for SWIR InGaAs photodetectors,” M.S. - Master of Science, Middle East Technical University, 2022.