Microscopic defects and homogeneity investigations in 4H-SiC epitaxial wafers by UV scanning photoluminescence spectroscopy

UV scanning photoluminescence spectroscopy is applied to 4H-SiC epitaxy characterization. In a first part, the technique is used for triangular defects characterization. The results show that two kinds of defects are present. Some defects are inclusion of cubic SiC which is confirmed by Raman spectroscopy. The other ones consist of staking faults of different thicknesses acting as quantum wells. In a second part, the effective lifetime profile is mapped for a whole 50 mm epitaxy using the variation of room temperature PL intensity versus excitation intensity