Research and development of ion implantation technique for SiC semiconductor have been performed. Hot-implantation of P ions into 6H-SiC raises the electron concentration in P-implanted n-type layers, showing that the hot-implantation enhances the electrical activation of P donors. The hole concentration in Al ion implanted 6H-SiC is found to increase due to co-implantation of C ions. This fact demonstrates that the electrical properties of Al-implanted p-type layers are improved by the C co-implantation. Using the ion implantation methods, SiC-based metal-oxide-semiconductor field-effect-transistors (MOSFETs) have been successfully fabricated. These results indicate that hot- and C co-implantations are quite useful for the fabrication of SiC devices.