In this study, we have used the microwave photoconductivity decay method to map excess carrier lifetimes in a n-type 3C-SiC wafer grown on an undulant Si substrate. We compared these lifetime maps with the distributions of strains and defects, which were observed using optical microscopy, Raman spectroscopy and pit distributions after molten NaOH etching. We found that excess carrier lifetimes in strained regions, which exhibit high densities of defects, are short. We also found that carrier lifetimes in strained regions at the cross sections of the 3C-SiC wafer are short. These results suggest that defects and strains in the wafer exhibit distributions similar to those of shortened carrier lifetimes.
Excess carrier lifetime map for a 3C-SiC wafer.