Durability Improvements for Detector Antireflection Treatments

HgCdTe imaging devices used in space applications require robust anti-reflection (AR) treatment on backside of CdZnTe substrate to adequately perform in harsh radiative environment. The rigors of this environment include extreme temperature cycling and high energy radiation. Multilayer AR coatings are subject to poor performance under these conditions. In Phase I, Surmet Corporation demonstrated that motheye surfaces could be etched into CZT substrates to provide optical performance equivalent to that of AR coatings. Motheye structures are known to offer benefits in terms of wider waveband and more tolerance to angle of incidence. The objectives of the proposed Phase II effort are to complete the optimization of these structures, demonstrate their durability, and demonstrate that the associated processing is compatible with detector fabrication state of art. Efficacy and durability of motheye AR technology will be demonstrated under simulated space system operating conditions. Surmet will work with the IR detector manufacturer to transition the technology towards the production line.