Evaluation of long carrier lifetimes in thick 4H silicon carbide epitaxial layers

The carrier lifetime of ∼265 μm thick n-type 4H silicon carbide epilayers prepared using the carbon-implantation/annealing method was evaluated. An extraordinarily long minority carrier lifetime of 18.5 μs and a high injection lifetime of 19.2 μs were evaluated from time-resolved photoluminescence and microwave photoconductivity decay measurements, respectively. Based on the relationship between the epilayer thickness and carrier lifetime, the influence of surface recombination on the carrier lifetime was eliminated, and the bulk lifetime and hole diffusion constant were discussed.