Graphitization effects induced by thermal treatments of 4H-SiC

4H-SiC is one of the most promising indirect wide-bandgap (3.3 eV) semiconductor for power devices used in the emerging area of high-voltage and high-temperature electronics as well as space and radiation harsh environments applications. The wide diffusion of devices in SiC is related to the high quality of the crystals, both for substrates and epitaxial layers. In this work, we performed thermal treatments in Argon atmosphere at temperatures below 2000°C with the aim to study the thermal stability of substrates of 4H-SiC. The wafer substrates were characterized by micro-Raman spectroscopy, Atomic Force Microscopy and Electrostatic Force Microscopy. The thermal treatments induced inhomogeneity of the wafer surface due to a graphitization process starting from 1600°C.