Silicon carbide epitaxial wafer is a kind of silicon carbide wafer on which a single crystal film (epitaxial layer) with certain requirements and the same crystal as the substrate is grown on the silicon carbide substrate. In practical applications, almost all wide band gap semiconductor devices are made on the epitaxial layer, and the silicon carbide wafer itself is only used as the substrate, including using as GaN epitaxial layer substrate.
Different from traditional silicon power devices, SiC power devices can not be directly fabricated on silicon carbide single crystal materials. High quality epitaxial materials must be grown on the conductive single crystal substrate, and all kinds of devices must be fabricated on the epitaxial layer.
Epitaxial process is a very critical process in the whole industry. Since all devices are basically realized in epitaxy, the quality of epitaxy has a great impact on the performance of devices. However, the quality of epitaxy is affected by the processing of crystal and substrate, which is in the middle of an industry and plays a key role in the development of the industry.