Lifetime-limiting defects in n− 4H-SiC epilayers

Low-injection minority carrier lifetimes (MCLs) and deep trap spectra have been investigated in $n^{-}$ 4H-SiC epilayers of varying layer thicknesses, in order to enable the separation of bulk lifetimes from surface recombination effects. From the linear dependence of the inverse bulk MCL on the concentration of $Z1∕Z2$ defects and from the behavior of the deep trap spectra in 4H-SiC $p\text{-}i\text{-}n$ diodes under forward bias, we conclude that it is $Z1∕Z2$ alone that controls the MCL in this material.