Passivation of Dislocation Defects by Hydrogenation for High Performance Longwave Infrared (LWIR) HgCdTe on Silicon

Production of low cost, large format HgCdTe LWIR focal plane arrays (FPAs) requires delivery of low defect density HgCdTe epilayers on Si. Despite the significant lattice mismatch between Si and HgCdTe several companies have demonstrated high performance MBE grown MWIR (3-5 microns)-HgCdTe devices on large-area Si substrates. This success has not translated directly to LWIR (8-12 microns)-HgCdTe detectors because of their increased sensitivity to defects. Amethyst Research Incorporated (ARI) has proposed that extension of HgCdTe on Si – based devices to LWIR and beyond can be readily achieved, with minimal modification to present FPA processing, by electrically neutralizing the defects originating at the substrate/epilayer interface using hydrogen passivation. In Phase I, ARI has demonstrated that hydrogen acts as a passivant in HgCdTe, can be readily introduced into the HgCdTe epilayer in controlled concentrations, and can be introduced at various stages of FPA processing. In Phase II, and in collaboration with Rockwell Scientific, ARI will develop the hydrogenation technology for full compatibility with HgCdTe FPA processing, improved diode characteristics, and FPA performance. ARI will deliver 640 x 480 LWIR HgCdTe- on Si FPA’s treated with the hydrogenation passivation process, and a fully documented design for a ‘plug-and-play’ large area hydrogenation system.