Investigation of the surface morphology of 4H-SiC Implanted with Low-Energy H and He Ions

Low-energy ions have the potential to be used for modifying materials on the nanoscale. We have investigated low-energy ion-implanted 4H-SiC, employing x-ray and neutron reflectivity to obtain depth and density while using real-space imaging to examine the effect of implantation on the surface morphology. The SiC was implanted with H and He ions at <1keV using a standard ion gun. Reflectivity measurements show a surface layer having a reduced density that is 60-65% of the density of SiC. The depth of this lower-density layer increases with sequential implantations. The combination of x-ray and neutron reflectivity reveal that H remains embedded in the SiC. Imaging techniques, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and Optical Profilometry (OP), show topographic surface defects. The number density for the area of these defects follows a power-law over several decades and confirms a surface density that is 60-80% of SiC, which is in agreement with the reflectivity results.