Material Characterization of 4H-SiC Using a Carbon Cap Protective Mask Before and After Al and P Ion Implantation: Effects on Surface Morphology

High‐bandgap semiconductor materials such as silicon carbide (SiC) have recently gained significant attention due to their superior electrical, thermal, and mechanical properties compared to conventional semiconductors like silicon (Si) [1,2]. Dopant ion implantation is a key step in fabricating SiC power devices; however, it often induces substantial surface damage, and the high‐temperature annealing (>1600 °C) required for dopant activation can cause surface roughening and step bunching. This study examines the influence of amorphous carbon (a‐C) cap layer on the preservation of surface morphology during ion implantation and post annealing process in 4H‐SiC. Wafers were implanted with aluminum (Al) and phosphorus (P) ions at various energies and doses at 500 °C, using a‐C cap layers of 20 nm and 50 nm thickness applied either before implantation (pre‐cap) or after implantation (post‐cap). Post‐implantation annealing was carried out at 1700 °C to activate dopants. Atomic Force Microscopy (AFM) was used to evaluate changes in surface roughness and morphology. The results demonstrate the role of carbon capping effectively suppresses surface degradation, minimizing roughness during high‐temperature annealing. These findings highlight the dual role of carbon capping as a protective barrier and implantation mask, offering a practical approach to improving surface quality and dopant activation in 4H‐SiC device processing.