Defects and carrier lifetime in 4H-Silicon Carbide

Silicon Carbide, especially the polytype 4H-SiC, is an ideal semiconductor material for power electronic devices and visible-blind UV photodiodes due to its intrinsic material properties such as, e.g., wide band-gap, low intrinsic carrier concentration, and high breakdown field. Although defect densities in 4H-SiC substrates and homoepitaxial layers have been reduced to fair levels in the last years, there is still room for further improvement: We will present the current status of structural defects in epilayers like stacking faults, dislocations and point defects, and compare these defect densities to those of other important semiconductor materials. These kinds of material defects can reduce lifetime and diffusion lengths of electrical carriers and hence, the device performance. We will focus on the correlation between point defects and minority carrier lifetime by Shockley-Read-Hall-recombination at deep levels and present different ways for lifetime engineering by epitaxial growth and post-epi processing in SiC technology.