Surface Evolution of Nano-Textured 4H–SiC Homoepitaxial Layers after High Temperature Treatments: Morphology Characterization and Graphene Growth

Nano-textured 4H-SiC homoepitaxial layers (NSiCLs) were grown on 4H-SiC(0001) substrates using a low pressure chemical vapor deposition technique (LPCVD), and subsequently were subjected to high temperature treatments (HTTs) for investigation of their surface morphology evolution and graphene growth. It was found that continuously distributed nano-scale patterns formed on NSiCLs which were about submicrons in-plane and about 100 nanometers out-of-plane in size. After HTTs under vacuum, pattern sizes reduced, and the sizes of the remains were inversely proportional to the treatment time. Referring to Raman spectra, the establishment of multi-layer graphene (MLG) on NSiCL surfaces was observed. MLG with sp² disorders was obtained from NSiCLs after a high temperature treatment under vacuum at 1700 K for two hours, while MLG without sp² disorders was obtained under Ar atmosphere at 1900 K.