Thickness and dopant density are key parameters of SiC epitaxial wafers. Epitaxial growth specifications primarily hinge on device design, and epitaxial wafer parameters vary depending on the voltage level of devices. The greater the thickness of epitaxial layers, the higher the breakdown voltage of devices made. Generally, 6 μm epitaxial wafers are required for 600V products, 10-15 μm for 1200-1700 V ones, and over 100 μm for above 10 KV ones.

SiC crystals will inevitably produce defects and introduce impurities in the growth process, resulting in both quality and performance of substrate material not good enough. The growth of the epitaxial layer can greatly eliminate certain defects in the substrate, keep the neatly arranged lattice in place, and regulate the dopant type and dopant density of the epitaxial layer. Today, almost all devices are implemented on the epitaxial layer, so the epitaxial wafer in high quality and low defect density has a decisive impact on the performance of devices.

SiC epitaxial wafer products can be widely used for power devices in photovoltaic energy storage, rail transit and new energy vehicles (NEVs).

Large size: The large-size SiC epitaxial wafer has a large usable area and lower cost, and can meet the demand for cost reduction and efficiency improvement. Given that 4-inch and 6-inch epitaxial wafers will gradually evolve to 8-inch ones, the large-size epitaxial wafer will account for a growing share each year;

Thick film: The greater the thickness of epitaxial layers, the higher the breakdown voltage of devices. As it can address the needs of high withstand voltage devices, the thick-film epitaxial wafer is also a key research direction in the future.