Low Trap Concentration and Low Basal-Plane Dislocation Density in 4H-SiC Epilayers Grown at High Growth Rate

Abstract

Fast homoepitaxial growth of 4H-SiC has been carried out on off-axis (0001) substrates by horizontal hot-wall CVD at 1600οC. High growth rate up to 24 μm/h has been achieved with mirror-like surface in the C/Si ratio range of 1.0-2.0. The Z1/2 and EH6/7 concentrations can be kept as low as 7 × 1011 cm-3 and 3 × 1011 cm-3, although an unknown trap (UT1) is observed with the concentration in the 1011 cm-3 range. The photoluminescence spectra are dominated by strong free exciton peaks, and the L1 peak is not observed. The basal-plane dislocation (BPD) density has decreased with increase in growth rate, and it can be reduced to 22 cm-2 when epilayers are grown on Chemical Mechanically Polished (CMP) substrates at a growth rate of 24 μm/h.