Influence of n-type doping levels on carrier lifetime in 4H-SiC epitaxial layers

In this study we have grown thick 4H-SiC epitaxial layers with different n-type doping levels in the range 1×10 ¹⁵ cm ^-3 to mid 1×10 ¹⁸ cm ^-3 , in order to investigate the influence on carrier lifetime. The epilayers were grown with identical growth conditions except the doping level on comparable substrates, in order to minimize the influence of other parameters than the n-type doping level. We have found a drastic decrease in carrier lifetime with increasing n-type doping level. Epilayers were further characterized with low temperature photoluminescence and deep level transient spectroscopy.