Low Roughness and Shape Reforming 4H-SiC Trench Process optimized by CCP Etching with High Temperature Annealing and Sacrificial Oxidation

This paper focuses on the evaluation of two subsequent process steps—post-trench processing (PTPs) and sacrificial oxidation (SAC)—following the etching of 4H silicon carbide (4H-SiC) trenches. Through hydrogen (H2) annealing followed by sacrificial oxidation, exceptionally low trench sidewall roughness of 0.24 nm and well-rounded, micro-trench-free SiC trenches were achieved. This study also presents a comparison study of SiC annealing processes using argon (Ar) and hydrogen (H2), as well as an examination of the roughness associated with the SiC sacrificial oxidation process. These findings contribute to enhancing the electrical performance of trench MOSFETs.