Defects Grouping and Characterizations of PL-Imaging Methods for 4H-SiC Epitaxial Layers

Abstract

4H-SiC epitaxial wafers were prepared for the investigation of epitaxial stacking faults (SFs), for the purpose of classification and add to the epitaxial specification by PL-imaging analysis. Black colored SFs detected in PL colored images were focused, and investigated. Black SFs in the PL images were classified for two species, ones were correspond to the triangular defects, and the others were similar to the known SFs. Triangular defects were the killer defects for the I-V properties and the other black defects were not affected the I-V properties. Most of PL spectrums of triangular defects had the 538nm peak, and showed the 3C properties. Black defects undetectable as the surface defects (SDs) had 460, 480nm peak, differed from the reported typical 1-4SSFs spectrum. It seemed that these defects differed from the thickness of stacking layer and PL peak, whether the defects led to detectable/undetectable as the SDs. Thick stacking layers generated the triangular defects, and thin ones generated the PL-black defects undetectable as the surface analysis. Consequently, the black defects undetectable as the surface analysis (detected only for the PL-imaging analysis) has no use for add to the specification at the moment.