Effect of TCS gas flow and pre-etching on homopitaxial growth of 4H-SiC

In this study, the epitaxial growth of 6-inch n-type 4 degrees off-axis Si-face substrates using a horizontal hot-wall LPCVD system was investigated. The study explored the epitaxial growth under different source gas flow rates, growth pressures, and pre-etching times, with particular emphasis on their effects on epitaxial growth rate, epitaxial layer thickness uniformity, doping concentration and uniformity, and epitaxial layer surface roughness. The observation was made that the increase in source gas flow rate led to variations in dopant concentration due to different transport models between nitrogen gas and source gas. Additionally, with the increase in etching time, overetching phenomena occurred, resulting in changes in both dopant concentration and uniformity. Furthermore, the relationships between these three factors and their corresponding indicators were explained by combining the CVD growth process with the laminar flow model. These observed patterns are beneficial for further optimizing growth conditions in industrial settings, ultimately enhancing the quality of the growth process. This study explored the epitaxial growth of 4H-SiC under various source gas flow rates, growth pressures, and pre-etching times, and their effects on growth rate, thickness uniformity, doping concentration and uniformity, and surface roughness.