The Reduction of Surface Defect of SiC Epitaxy by Improved in-situ Etching Process

Silicon carbide has superior power conversion efficiency and is expanding its applications to high-voltage, high-power sectors such as wind power, railways, and electric vehicles. As demand for high-quality, thick epitaxial materials increases, the importance of epitaxial layers, which define the operating region of the device is increasing. With the required SiC epitaxy properties becoming more sophisticated, the demand for diverse specifications and high-quality characteristics is also increasing. 

To suppress the occurrence of surface defects during SiC epitaxial growth, we optimized the conditions of in-situ etching process, which is the initial step in epitaxial growth. Etching, which removes the damaged layer on the substrate surface, is typically performed in a high-temperature hydrogen atmosphere. To enhance the efficiency of the etching process, a chlorine-containing gas was added, and to mitigate carbon deficiency at the surface, a carbon-containing gas was introduced. The process incorporating both chlorine- and carbon-containing gases achieved the lowest surface defect density of 0.39 /cm².