Time-resolved imaging of radiative recombination in 4H–SiC p-i-n diode

The time-resolved imaging of electron-hole recombination radiation from a forward-biased 4H–SiC p-i-n diode is reported. A novel approach of combining gated charge couple device technique with cross-sectional emission microscopy is demonstrated as a fast and informative method for characterization of both 4H–SiC material properties and the overall power device performance. We present the capability of the technique to visualize structural defects, to characterize spatial distribution and dynamics of injected carriers, and to provide effective carrier diffusion and lifetime parameters. From the results of lateral and in-depth imaging of the light emission we conclude that at low currents the injection of holes from the p+ emission is dominant. Furthermore, an effective carrier lifetime of 350 ns in the active n− region and a diffusion length of 15 μm in the substrate are readily obtained.