Influence of H2 Flow Rate and Growth Temperature on Homoepitaxial Growth and Doping of 4H‐SiC by Chemical Vapor Deposition

In recent years, silicon carbide (SiC) epitaxy has attracted increasing interest for wide applications such as advanced power and radio‐frequency electronics. Despite extensive research, the influences of hydrogen (H2) flow rate and growth temperature for epitaxy on large‐diameter substrates remain insufficiently explored. In this work, homoepitaxial 4H‐SiC films were grown on 150 mm, 4° off‐axis substrates using a hot‐wall chemical vapor deposition reactor. The distributions of thickness and ammonia doping concentration and the surface morphology evolution were systematically characterized. An innovative normalized radial distribution analysis method was developed to enable clear, unbiased comparison of thickness or doping profiles and to provide a robust basis for trend evaluation and process‐parameter optimization across the wafer. As the H2 flow rate decreased, the thickness distribution became increasingly concave, whereas the doping concentration distribution exhibited a nonmonotonic variation. Compared with the H2 flow rate, the temperature change had a minor impact on the distribution profiles and the variation of uniformity. Further reductions in H2 flow rate and growth temperature led to distinct nonflat microstructures and surface morphology evolutions. Low H2 flow rate or temperature induced surface roughening and the formation of nonflat microstructures, such as particles, triangles, and multidomains, which were identified as 3C‐SiC by Raman spectroscopy. Excessively low H2 flow rates and growth temperatures led to a decline in crystalline quality. These results elucidate the distinct roles of H2 flow and temperature, providing insights for improving uniformity and crystalline quality in large‐area SiC epitaxial growth.