Behaviour of 4H-SiC pin diodes studied by numerical device simulation

We simulated and measured the forward characteristics of 4H-SiC pin diodes in a wide temperature range from 300K to 700K. Our simulations are based on the stationary drift-diffusion model including a model for incomplete ionization of the dopants. Physically based models for Auger recombination and Shockley-Read-Hall recombination are used as well. For the mobility model the empirical relation of Caughey-Thomas is used. The model parameters to be calibrated in the simulation are the electron and hole minority lifetimes and the electron and hole bulk mobilities. Employing temperature-dependent carrier lifetimes we achieved very good agreement between simulations and measured data. For the temperature- and doping-dependent carrier mobilities we found that the best fit is obtained for a bulk mobility value much smaller than that suggested by standard parameters for 4H-SiC. With the calibrated parameters we simulated the internal carrier distributions for temperatures up to 700 K and for different carrier lifetimes.