High temperature ion-implantation of arsenic (As+) into the 4H-silicon carbide (SiC) substrates with high dose of 7X10(15) cm(-2) has been investigated as an effective doping technique of n-type dopant for SiC power electron devices fabrication. The R-s as low as 213 Omega/square is achieved in the sample implanted at 500 degreesC and annealed at 1600 degreesC. AFM and SIMS results reveal that the surface roughness of implanted SiC increases with the increasing of post-annealing temperature. This result suggests that the evaporation of Si atoms and As+ dopants from SiC surface decreases the thickness of As+ implanted layer and makes effect on R-s of the sample annealed at higher temperature.