Influence of the C∕Si Ratio on the Dopant Concentration and Defects in CVD Grown 3C-SiC Homoepitaxial Layers

Abstract

The study reports on structural and optical investigations of (111) 3C‐SiC layers grown homoepitaxially by Chemical Vapour Deposition (CVD) at different C/Si ratios. The seeds were 3C‐SiC layers grown on on‐axis Si‐face (0001) 6H‐SiC substrates by Vapour‐Liquid‐Solid (VLS) mechanism in Si‐Ge or Si‐Sn melt. Transmission Electron Microscopy (TEM) investigation showed that the main defects reaching the VLS seed surface are dislocations, stacking faults (SFs) and twin boundaries. In the CVD layer the defect density is reduced compared to the VLS layer at low C/Si ratio (in the range of 1–3). The low‐temperature Photoluminescence (LTPL) spectra of all the layers display a defect related peak at 1.98 eV attributed to DI defect, while G bands are observed in the range of 1.82–1.92 eV range at C/Si ratio of 7 and 10. Common defect in CVD layers was multiple twin complex, which appears as a rule at the vicinity of the twinned domains. This multiple twin complex consists of four twins bound by two fully symmetrical...