Modelling of Effective Minority Carrier Lifetime in 4H-SiC n-Type Epilayers

Abstract

We present an extended model for the simulation of the effective minority carrier lifetime in 4H-SiC epiwafers after optical excitation. This multilayer model uses measured values (such as doping profile, point defect concentration and capture cross sections, epilayer thickness) as input parameters. The bulk lifetime and the diffusion constant are calculated from the actual time dependent excess carrier profiles, resulting in more realistic transients having different decay regimes than in other models. This enables a better understanding of optical lifetime measurements.

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“…However, the lifetime is mainly limited by the so‐called Z1/2 defect which is correlated with carbon vacancies. IISB is conducting lifetime engineering in SiC investigating how the lifetime can be increased and how the carbon vacancies can be decreased . This problem cannot be solved by only optimizing the epi‐process with respect to low carbon vacancy concentrations.…”