Deep Electron and Hole Traps in 6H-SiC Bulk Crystals Grown by the Halide Chemical Vapor Deposition
Deep electron and hole traps were studied in a series of high purity 6H-SiC single crystals grown by Halide Chemical Vapor Deposition (HCVD) method at various C/Si flow ratios and at temperatures between 2000 oC and 2100 oC. Characterization included Low Temperature Photoluminescence (LTPL), Deep Level Transient Spectroscopy (DLTS), Minority Carrier Transient Spectroscopy (MCTS), and Thermal Admittance Spectroscopy (TAS) measurements. Concentrations of all deep traps were shown to strongly decrease with increased C/Si flow ratio and with increased growth temperature. The results indicate that the majority of deep centers in 6H-SiC crystals grown by HCVD are due to native defects or complexes of native defects promoted by Si-rich growth conditions. The observed growth temperature dependence of residual donor concentration and traps density is explained by increasing the effective C/Si ratio at higher temperatures for the same nominal ratio of C and Si flows.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
S. W. Huh et al., "Deep Electron and Hole Traps in 6H-SiC Bulk Crystals Grown by the Halide Chemical Vapor Deposition", Materials Science Forum, Vols. 527-529, pp. 497-500, 2006