Development of high performance radiation hardened antireflection coatings for LWIR and multicolor IR focal plane arrays

ABSTRACT High Performance Radiation Hardened LWIR and Multicolor Focal Plane Arrays are critical for manyspaceapplications. Reliable focal plane arrays are needed for these applications that can operate in space environment withoutanydegradation.In this paper, we will present various LWIR and Multicolor Focal Plane architectures currentlybeing evaluated forLWIR and Multicolor applications that include focal planematerials such as HgCdTe, PbSnTe, QWIP and otherSuperlattice device structures.We also present AR Coating models and experimental results on several promising multi-layer AR coatings that includesCdTe, Si 3 N 4 and diamond like Carbon, that have the necessary spectral response in the 2-25 microns and are hardmaterials with excellent bond strength. A combination of these materials offers the potential of developing anti-reflectioncoatings with high optical qualitywith controlled physical properties. INTRODUCTON Reliable LWIR focal planearrays are needed for space applications that can operate in space environment without anydegradation. Some of the technologies being developed for the Next Generation include HgCdTe (1, 2), PbSnTe (3) andQWIP (4) IR focal plane arrays. While HgCdTe and PbSnTe are being grown on silicon substrates, the QWIP focalplane arrays use GaAs substrates. The advantages of Silicon substrate for HgCdTe and PbSnTe, include the ability to