Rapid, Contactless, Non-destructive CdZnTe Substrate Defect Screening System for Epitaxial Growth of HgCdTe

CdZnTe is the substrate material of choice for the growth of high-performance, lattice-matched infrared HgCdTe epitaxial materials used in the fabrication of high-end focal plane arrays (FPAs). However, the device fabrication yield is dramatically reduced by large defects in the HgCdTe film which causes many adjacent defective pixels. Recently, NVESD infrared group has identified the imperfect CdZnTe substrate as the cause of some of these defects. The goal of this proposal is to develop rapid, wafer-scale, non-destructive, contactless, and comprehensive techniques for detecting and characterizing these identified defects in the CdZnTe substrate, as well as other yield-and performance-limiting,  yet unidentified CdZnTe defects. In this proposed Phase 1 work, EPIR will develop and implement the experimental apparatus that will allow us to unambiguously locate the CdZnTe substrate defects and correlate them with the defects identified in the epitaxially grown HgCdTe layers. The proposed technique is based on multiple optical 3D mapping and imaging analyses using advanced image processing algorithms for quick CdZnTe defect detection and substrate screening. The system will be able to generate a 3D substrate wafer-scale map of these defects. These capabilities promise to improve HgCdTe material yield for the fabrication of high-performance FPAs.