HOT MWIR technology at SCD

SCD is a leading manufacturer of MWIR InSb Focal Plane Arrays (FPA) with formats up to 3 megapixels. Using photodiode layers grown by Molecular Beam Epitaxy (MBE), the operating temperature is raised to similar to 100 K, compared with 80 K for our legacy implanted junction technology. Due to the excellent manufacturability of III-V MBE materials, we have extended this approach in the development of our newer High Operating Temperature (HOT) MWIR technologies, all of which are based on XBn and XBp barrier devices which suppress the dark current generated by traps in the depletion layer. As a result we now produce a family of InAsSb XBn FPAs operating at 150 K with a cut-off wavelength of lambda(C) = 4.2 mu m Formats range between 0.33 megapixels and 5.24 megapixels and our latest "Crane" FPA has a pitch of just 5 mu m. These detectors are ideal for 24/7 surveillance and long-range applications, due to large formats, increased HOT cooler reliability and very high atmospheric transmission. For applications requiring HOT full MWIR (HFMW) performance (lambda(C) = similar to 4.9 mu m), we have explored three approaches, all of which have produced operating temperatures in the range 115- 125 K with high FPA operability and uniformity. Using a suitable design of buffer layer, we have extended the InAsSb XBn cut-off wavelength while maintaining a high quantum efficiency above 70%. Comparable performance has also been obtained in two lattice matched type II superlattice (T2SL) architectures: XBn InAs/InAsSb and XBp InAs/GaSb. The three technologies give great flexibility in design optimization, and initial production of HFMW detectors is scheduled for mid 2022.