Radiation-Hardened, Substrate-Removed, Metamorphic InGaAs Detector Arrays

High-performance radiation-hardened metamorphic InGaAs imaging arrays sensitive from the ultraviolet (UV) through the short-wavelength infrared (SWIR) will be developed. The proposed detector arrays will offer near-BLIP sensitivity, with R0A values comparable to HgCdTe detectors, but with superior sensitivity, better uniformity, lower dark current, and much better pixel yield. Typical InGaAs detectors have little response beyond 1650 nm due to the band edge of the InGaAs alloy composition that is lattice-matched to the InP substrate, and the InP substrate blocks short wavelength response below 950 nm in back-illuminated focal plane arrays. The proposed detector will employ low-dislocation-density metamorphic InGaAs to extend long wavelength response to 2.6 um. Chemical/mechanical substrate removal and a surface doping gradient designed to collect photocarriers generated near the light-entry surface of the detector will extend its short-wavelength response. Prototype single-element detectors and segmented arrays will be demonstrated in Phase I. In Phase II, material quality will be refined through additional manufacturing development, and large area arrays will be fabricated. By the end of Phase II, extended-spectral-range InGaAs imagers based upon the new metamorphic detector and a radiation-hardened readout integrated circuit (ROIC) will be demonstrated.Voxtel anticipates that its technology will enter the program at TRL=3, finish Phase I at TRL=5, and exit the Phase II program at TRL=6.