Investigation of Photoluminescence Black Features in 4H‐SiC Substrates

In recent years, photoluminescence (PL) black features in 4H‐SiC recorded by a surface inspection tool have plagued substrate suppliers, epitaxy and device manufacturers, as both their root causes and adverse effects remain unclear. This study shows that PL blacks correspond to threading dislocations (TDs) and basal plane dislocations (BPDs). Substrates exhibiting different PL black characteristics are found to present distinct peak profiles in their PL spectra, indicating differences in point defect‐related recombination processes. The elimination of PL black features following annealing is attributed to the increased formation of radiative recombination centers in the long‐wavelength spectral range, particularly in regions surrounding dislocations. These results establish a link between point defects and PL images, facilitating more effective characterization and investigation of point defects in silicon carbide substrates.