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

The time-resolved imaging of electron-hole recombination radiation from a f orward-biased 4H-SiC p-i-n diode is reported. A novel approach of combining gated charge couple device technique with cross-sectional emission microsc opy is demonstrated as a fast and informative method for characterization o f 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, a nd 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 domin ant. Furthermore, an effective carrier lifetime of 350 ns in the active n(- ) region and a diffusion length of 15 mu m in the substrate are readily obt ained. (C) 1999 American Institute of Physics. [S0003-6951(99)00722-6].