Third-generation infrared detector program at SCD

Abstract

Antimonide Based Compound Semiconductors (ABCS) and a new family of advanced analogue and digital silicon read-out integrated circuits form the basis of the SCD 3rd generation detector program, which builds on the firm platform of SCDs existing InSb-FPA technology. In order to cover the MWIR atmospheric window, we recently proposed the epitaxial alloys: InAs1-y Sby on GaSb with 0.07 < y < 0.11 and In1-zAlz Sb on InSb with 0 < z < 0.03. In this paper we focus on the results of some of our recent work on epitaxial In1-zAlz Sb grown on InSb by Molecular Beam Epitxay (MBE). In epitaxial InSb (z = 0), we demonstrate the performance of Focal Plane Arrays (FPAs) with a format of 320x256 pixels, at focal plane temperatures between 77K and 100K. An operability has been achieved which is in excess of 99.5%, with a Residual Non-Uniformity (RNU) at 95K of less than 0.03% (standard deviation/dynamic range). Moreover, after a two point Non-Uniformity Correction (NUC) has been applied at 95K, the RNU remains below ~0.1% at all focal plane temperatures down to 85K and up to 100K without the need to apply any further correction. This is a major improvement in both the temperature of operation and the temperature stability compared with implanted diodes made from bulk material. We also demonstrate rapid progress in the development of low current epitaxial InAlSb photodiodes with high uniformity and low dark current that offer a range of cut-off wavelengths shorter than in InSb. Preliminary results are presented on FPAs with a cut-off wavelength in the range λC~5μ.