Surface damage to a 4H-SiC single-crystal substrate caused by dual-fluid spray cleaning

The surface state of 4H-SiC single-crystal substrates has emerged as a critical factor limiting the quality of epitaxial layers and device performance. Cleaning, being the final step of processing, directly influences the surface state of 4H-SiC single-crystal substrates. Single-wafer wet chemical cleaning is valued for its high cleaning capacity. In this work, the application of a dual-fluid spray cleaning process in single-wafer cleaning of a 4H-SiC single-crystal substrate was studied. Specifically, the mechanism underlying the formation of the white circle defects generated during this process was investigated in detail. Furthermore, the characteristics of white circle defects were analysed, and correlations between the relevant process parameters were established. This study has significant implications for enhancing removal of pollutants from 4H-SiC single-crystal substrates.