Characterization of carrier lifetime and diffusivity in 4H–SiC using time-resolved imaging spectroscopy of electroluminescence

We report on time- and spectrally resolved studies of recombination radiation in 4H–SiC by combining imaging spectroscopy and gated optical emission microscopy techniques. An insight into the basic characteristics of 3D carrier dynamics was attained by combining data of electroluminescence imaged from the backside and from the cross-sectional plane of a forward biased PN structures. We demonstrate the potential and efficiency of this method in mapping minority carrier lifetime and diffusivity parameters and also in locating and analysis of the structural defects in the active area. Finally, a detrimental impact of the intrinsic growth-related and long-term operation-induced defects on the carrier transport properties was directly revealed and quantified.