Influence of substrate properties on the defectivity and minority carrier lifetime in 4H-SiC homoepitaxial layers

Two fully loaded epitaxial growth runs with 16 wafers in total were conducted in the AIXTRON G5 WW reactor in order to keep epigrowth conditions constant. The wafers were selected with a large spread of specific resistivity and dislocation densities. The resulting epilayers showed very good intra-wafer homogeneities as well as excellent wafer-to-wafer and run-to-run reproducibility with regard to epilayer thickness and doping concentration, point defect concentrations of Z1/2 and EH6/7 and the resulting Shockley-Read-Hall carrier lifetime. We found that the dislocation densities of the underlying substrates are influencing the stacking fault densities of the epilayers, which then vary between 0.1 and 10 cm-2. A substrate effect on the effective minority carrier lifetime was found.