128 × 128 long-wavelength/mid-wavelength two-color HgCdTe infrared focal plane array detector with ultralow spectral cross talk.

Abstract

High temporal and spatial coherent simultaneous long-wavelength/mid-wavelength (LW/MW) two-color focal plane array (FPA) infrared detection is the cutting-edge technique for third-generation infrared remote sensing. In this Letter, HgCdTe LW/MW two-color infrared detectors were designed and fabricated. The top long-wavelength and bottom mid-wavelength infrared planar photodiodes were processed by selective B(+)-implantation after etching the long-wavelength epilayer into a curvature and exposing the mid-wavelength layers for the implantation of the n region of the MW photodiode by a micro-mesa array technique. A 128×128 MW/LW HgCdTe infrared FPA detector is fabricated photo-lithographically by simultaneous nonplanar B(+)-implantation of the LW and MW photodiodes, passivation and metallization of the sidewalls, mesa isolation, and flip-chip hybridization with a read-out integrated circuit. The inner mechanisms for suppressing the cross talk and improving photoresponse have been carried out by combining experimental work with numerical simulations.